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Assessment and Design of Properties for Flowable Fill Usage in Highway Pavement Construction for Conditions in Florida


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ASSESSMENT OF DESIGN AND PROPERTIES FOR FLOWABLE FILL USAGE IN HIGHWAY PAVEMENT CONSTRUCTION FOR CONDITIONS IN FLORIDA By WEBERT LOVENCIN A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLOR IDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLORIDA 2007

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Copyright 2007 by Webert Lovencin

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I would like to dedicate this disserta tion to my parents, my lovely wife, April Adrienne Raines-Lovencin, my sister, Natacha Egland, my nieces and nephews, and to the tax payers who help fund the public education systems in the state of Florida.

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iv ACKNOWLEDGMENTS I would like to acknowledge t hose individuals who were involved in the advancement of this research and throughout my studies First, I would like to express my most sincere gratitude to Dr. Fazil T. Najafi, my advisor and supervisory committee chairman. Dr. Najafi has been a mentor, a friend, a nd a continuous source of encouragement both professionally and personally. I thank Dr. Mang Tia, the cochair of my committee, for his valuable advice and suggestions thr oughout the research study and dissertation. I would also like to than k the other members of my committee, Dr. Walter E. Dukes, Dr. David J. Horhota, Mr. Timothy J. Ruelke, and Mr. Michael J. Bergin, for their continued support, constructive comments, a nd recommendations during my tenure at the University of Florida. Many debts of gratitude go out to the folks at the Florida Department of Transportation State Materials Office (Physical Lab a nd Geotechnical Division s) and District 2 Materials Office in Lake City, who assist ed me with this research study. These individuals include Richard De lorenzo, Craig Roberts, Terry Thomas, Tim Blanton, Mike Davis, Glenn Johnson, Ben Watson, Willie He nderson, Chris Falade, Bobby Ivory, Scott Clayton, and Daniel Langley. I would also like to express my gratitude to Drs. Claude Villiers and Jonathan F. Earle, and Mrs. Margie Williams for their continuous encouragement and support, as well as Mrs. Candace J. Leggett for her immense pa tience and efficient editorial assistance with writing this dissertation.

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v Finally, I want to specially thank my sa vior, God (Jehovah), my family in the United States and abroad from where they have always conferred me their support and for believing in me the way they do. But above all, I want to deep ly thank my beloved wife, April, for her immense love, indispensa ble help and patience. April has been the sole person responsible for my achieving this goal. She has been th e wall containing my worry, my best critic, an d my greatest supporter.

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vi TABLE OF CONTENTS page ACKNOWLEDGMENTS.................................................................................................iv LIST OF TABLES...............................................................................................................x LIST OF FIGURES..........................................................................................................xii ABSTRACT....................................................................................................................xvii CHAPTER 1 INTRODUCTION........................................................................................................1 1.1 Background............................................................................................................1 1.2 Problem Statement.................................................................................................2 1.2.1 Strength........................................................................................................2 1.2.2 Shrinkage.....................................................................................................3 1.3 Hypothesis.............................................................................................................5 1.4 Objectives..............................................................................................................6 1.5 Scope..................................................................................................................... .6 1.6 Importance of Research.........................................................................................6 1.7 Research Approach................................................................................................7 1.8 Outline of the Dissertation.....................................................................................9 2 LITERATURE REVIEW...........................................................................................10 2.1 Introduction..........................................................................................................10 2.2 Flowable Fill Technology....................................................................................10 2.2.1 Introduction...............................................................................................10 2.2.2 Types of Flowable Fill...............................................................................11 2.2.3 Advantages of Using Controlle d Low Strength Material (CLSM)...........11 2.2.4 Engineering Characteristics of CLSM.......................................................13 2.2.5 Uses of Flowable Fill.................................................................................13 2.2.6 Delivery and Placement of Flowable Fill..................................................14 2.2.7 Limits.........................................................................................................15 2.3 Specifications, Test Methods, and Practices........................................................15 2.3.1 Introduction...............................................................................................15 2.3.2 ASTM Standard Test Methods..................................................................17

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vii 2.3.2.1 Standard Test Method for Preparation and Testing of CLSM Test Cylinders (ASTM D 4832-02)..............................................17 2.3.2.2 Standard Practice for Sampling Freshly Mixed CLSM (ASTM D 5971-96)..................................................................................18 2.3.2.3 Standard Test Method for Un it Weight, Yield, Cement Content and Air Content (Gravimetric) of CLSM (ASTM D 6023-96)................18 2.3.2.4 Standard Test Method for Ball Drop on CLSM to Determine Suitability for Load Application (ASTM D 6024-96)..............................19 2.3.2.5 Standard Test Method for Flow Consistency of CLSM (ASTM D 6103-96)..................................................................................20 2.3.3 Other Currently Used a nd Proposed Test Methods...................................20 2.3.4 Specifications by the State De partments of Transportation......................22 2.3.5 Use of Flowable Fill in the State of Florida..............................................24 2.3.5.1 Material Specifications (Section 121-2)..........................................24 2.3.5.2 Construction Requirement s and Acceptance (Section 121-5, 121-6)............................................................................................25 2.3.5.3 Guideline for Construction Requirements and Acceptance (Section 121-5, 121-6)..............................................................................25 2.4 Early Set and Strength Development...................................................................26 2.4.1 Introduction...............................................................................................26 2.4.2 Behavior of Slurries...................................................................................26 2.4.3 Early Hydration of Cement Particles.........................................................27 2.4.4 Influence of Water to the Hydration of Cement........................................28 2.4.5 Effects of Set Accelerator on Hydration of Cement..................................29 2.4.6 Set Time.....................................................................................................29 2.4.7 Strength Development...............................................................................30 2.4.8 Use of Mineral Admixture (Fly Ash and Granulated Ground Blast Furnace Slag) in Flowable Fill.........................................................................31 2.4.8.1 Fly ash.............................................................................................31 2.4.8.2 Slag.........................................................................................................34 2.4.8.3 Difference between fly ash and slag................................................36 2.4.8.4 Specific applications.......................................................................36 2.4.8.5 Mixture proportioning/mixture compliance....................................36 2.4.9 Effect of Moisture on Strength..................................................................37 2.5 Strength Prediction Models.................................................................................38 2.5.1 Introduction...............................................................................................38 2.5.2 Hamilton CountyRemovability Index.....................................................38 2.5.3 Bhats Study..............................................................................................39 2.5.4 NCHRPStudy..........................................................................................40 2.6 FDOT/UF Flowable Fill Study............................................................................42 3 MATERIALS AND LABORATORY EXPERIMENTAL PROGRAM...................44 3.1 Introduction..........................................................................................................44 3.2 Experimental Design...........................................................................................44 3.2.1 Rationale for Selecting Mixture Parameters..............................................44 3.2.2 Mixture Proportioning...............................................................................46

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viii 3.2.3 Specimen Sample Collection per Batch Mix.............................................49 3.2.4 Specimen Molds........................................................................................49 3.2.5 Fabrication of Flowable Fill Specimens....................................................50 3.2.5.1 Preparation of molds.......................................................................50 3.2.5.2 Mixing of flowable fill....................................................................50 3.2.5.3 Casting of flowable fill....................................................................53 3.3 Limerock Bearing Ratio Test (Florida Test Method 5-515)................................55 3.4 Compressive Strength Test..................................................................................60 3.5 Proctor Penetrometer Test...................................................................................64 3.6 Drying Oven........................................................................................................65 3.7 Drying Shrinkage of Flowable Fill Mixtures.......................................................65 3.7.1 Method 1....................................................................................................66 3.7.2 Method 2....................................................................................................69 3.7.3 Method 3....................................................................................................70 3.8 Materials..............................................................................................................71 3.8.1 Cement.......................................................................................................71 3.8.2 Fly Ash......................................................................................................72 3.8.3 Blast Furnace Slag.....................................................................................72 3.8.4 Aggregates.................................................................................................73 3.8.4.1 Aggregate gradation........................................................................74 3.8.4.2 Physical properties, absorption and moisture content.....................76 3.8.4.3 Storage of fine aggregates...............................................................77 3.8.5 Admixtures................................................................................................78 3.8.6 Water.........................................................................................................78 4 LABORATORY RESULTS AND DISCUSSIONS..................................................79 4.1 Introduction..........................................................................................................79 4.2 Laboratory Results...............................................................................................79 4.2.1 Limerock Bearing Ratio (LBR).................................................................79 4.2.2 Compressive Strength (psi).......................................................................79 4.2.3 Volume Change.........................................................................................84 4.2.4 Proctor Penetrometer Setting Strength (psi)..............................................85 4.2.5 Strength Gained Between 28 and 56 Days................................................91 4.2.6 LBR Oven Sample Results........................................................................92 4.3 Factors Affecting Strength...................................................................................96 4.3.1 Water-to-Cement (w/c) Ratio....................................................................96 4.3.2 Cement Content.........................................................................................98 4.3.3 Effect of Air Content on Strength...........................................................100 4.3.4 Effect of Mineral Admixtures (Fly Ash and Blast Furnace Slag) on Strength..........................................................................................................101 4.4 Comparison of Mix Using Type I/II Cement vs. Type I Cement......................102 4.5 Drying Shrinkage (Volume Change).................................................................105 4.6 Interpretation of Plastic Test Results.................................................................108

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ix 5 STATISTICAL ANALYSIS....................................................................................111 5.1 Introduction........................................................................................................111 5.2 Statistical Model Derivation..............................................................................111 5.3 Accelerating Strength Testing...........................................................................118 5.3.1 Background..............................................................................................118 5.3.2 Accelerated Curing..................................................................................119 5.3.3 Analysis...................................................................................................119 5.3.4 Confidence Band for Regression Line....................................................124 5.3.5 Estimate of Later Strength.......................................................................124 5.3.6 Analysis on Other Samples.....................................................................125 5.4 Model Validation and Evaluation of Accuracy.................................................128 5.4.1 Varying Strength Predic tion Models for Trend.......................................128 5.4.2 Comparison of Strength Prediction Models............................................145 5.4.3 Mixture Design Examples to Validate Models.......................................150 5.5 Summary of Model Equations and Limitations.................................................157 6 SUMMARY, CONCLUSIONS AND RECOMMENDATIONS............................164 6.1 Summary............................................................................................................164 6.2 Conclusions........................................................................................................166 6.3 Recommendations..............................................................................................167 APPENDIX A FLOWABLE FILL STUDY BATCH MIX DESIGN MATRIX.............................169 B LBR AND COMPRESSIVE STRENGTH DATA OBTAINED IN THE LABORATORY.......................................................................................................185 C ANALYSIS OF VARIANCE (ANOVA), PARAMETERS, AND STANDARD ERROR FOR MODELS....................................................................200 D ESTIMATED 28AND 56-DAY STRENGTH.......................................................215 LIST OF REFERENCES.................................................................................................252 BIOGRAPHICAL SKETCH...........................................................................................257

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x LIST OF TABLES Table page 2-1. Current ASTM standards on contro lled low strength material (CLSM)...................16 2-2. States surveyed and their specification on flowable fill............................................22 2-3. Specified acceptance strengths and ages...................................................................23 2-4. Suggested mixture proportions, lb/yd3 .....................................................................23 2-5. FDOT materials sp ecification requirements..............................................................24 2-6. FDOT flowable fill mix design.................................................................................25 2-7. Removability modulus ( RE )......................................................................................39 3-1. Mixture parameters....................................................................................................45 3-2. Summary of sample specimens collected per mix.....................................................49 3-3. Properties of fresh flow able fill (Experiment 1)........................................................56 3-4. Properties of fresh flow able fill (Experiment 2)........................................................57 3-5. Specifications for LBR test equipment......................................................................59 3-6. Chemical composition of cement used......................................................................71 3-7. Physical characteristics of cement.............................................................................72 3-8. Chemical and physical analyses of fly ash................................................................73 3-9. Chemical and physical an alyses of blast furnace slag...............................................73 3-10. Fine aggregate location source................................................................................74 3-11. ASTM C33-02A and FDOT specifica tions for fine aggregate gradation...............75 3-12. Physical properties of fine aggregates (silica sand).................................................76 4-1. LBR strength results for Experiment #1....................................................................80

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xi 4-2. LBR strength results for Experiment #2....................................................................81 4-3. Compressive strength results for Experiment #1.......................................................82 4-4. Compressive strength results for Experiment #2.......................................................83 4-5. Volume change results for Experiment #1................................................................86 4-6. Volume change results for Experiment #2................................................................87 4-7. Mix proportions and proctor penetr ometer results for Experiment #1......................88 4-9. Two-day oven LBR strength results for Experiment #1............................................93 4-10. Two-day oven LBR strengt h results for Experiment #2..........................................94 4-11. Comparison of mixture component s and their influence on accelerated 2-day oven and 28-day LBR strength......................................................................95 4-12. Comparison of mixture component s and their influence on percent volume change........................................................................................................106 5-1. Standard error of regression coe fficients for equations relating mixture constituents to LBR, compressive strength and percent volume change...............116 5-2. Estimation of confidence interval for 28-day strength............................................122 5-3. Summary of regression equatio ns for accelerated (oven) 28-day and 56-day LBR strength.......................................................................................127 5-4. NCHRPs CLSM mixture propor tions and fresh properties [38]............................146 5-5. Comparison of the NCHRP measur ed and predicted 28-day strength for air-entrained mixtures strength prediction model.............................................147 5-6. Comparison of estimated 28-day compressive strength..........................................149 5-7. Summary of materials re quired for validation mixtures..........................................154 5-8. Summary of plastic propertie s of validation mixture models..................................155 5-9. Comparison of estimated a nd experimental results for batch mixes 1v through 6v.....................................................................................158 5-10. Comparison of estimated a nd experimental results for batch mixes 7v through 11v...................................................................................159 5-11. Summary of recommended strength prediction equations listed with variables and range.........................................................................................162

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xii LIST OF FIGURES Figure page 1-1. Laboratory task process...............................................................................................8 2-1. Influence of water/cement (w/c) ratio on the setting of Portland cement paste........28 2-2. Bhats strength prediction model...............................................................................40 3-1. Concrete mixer used in study....................................................................................51 3-2. Pressure meter test for air content.............................................................................52 3-3. Cast flowable fill in LBR samples.............................................................................53 3-4. Cast flowable fill in 4-in. 8-in. (compressive strength) samples............................54 3-5. Cast flowable fill in 6-in. 12-in. (volume change) samples...................................54 3-6. Cross section of seated LBR penetration piston [30]................................................58 3-7. LBR machine.............................................................................................................59 3-8. Graph example showing typica l load penetration curve that requires no correction...............................................................................................61 3-9. Graph example showing correcti on of typical load penetration curve for small surface irregularities........................................................................62 3-10. Typical set-up for compressive strength test...........................................................63 3-11. Typical proctor penetrometer..................................................................................64 3-12. Test set-up for measur ing shrinkage using LVDTs.................................................68 3-13. Schematic of test set-up for measuring shrinkage using LVDTs............................68 3-14. Three-dial gauge reading method ...........................................................................69 3-15. Dial gauge shrinkag e reading being taken...............................................................70 3-16. Gradation of fine aggregatesASTM specs.............................................................75

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xiii 3-17. Gradation of fine aggregatesFDOT specs.............................................................76 3-18. Storage and removal of fine aggregates..................................................................77 4-1. Load deformation responses for batc h mix #4, at 3-, 28and 56-day duration.........84 4-2. Percent increase in 56-day strength as compared to 28-day strength (LBR)............91 4-3. Percent increase in 56-day strength as compared to 28-day strength (psi)...............92 4-4. Relationship between 28-day beari ng strength (LBR) and w/c ratio at 7.5% design air content.....................................................................................................96 4-5. Relationship between 28-da y bearing strength (LBR) and w/c ratio at 17.5% de sign air content.......................................................................96 4-6. Relationship between 28-day compressive strength (psi) and w/c ratio at 7.5% de sign air content.........................................................................97 4-7. Relationship between 28-day compressive strength (psi) and w/c ratio at 17.5% de sign air content.......................................................................97 4-8. Relationship between 28-da y bearing strength (LBR) and cement content at 7.5% design air content...............................................................98 4-9. Relationship between 28-da y bearing strength (LBR) and cement content at 17.5% design air content.............................................................98 4-10. Relationship between 28-day co mpressive strength (psi) and cement content at 7.5% design air content...............................................................99 4-11. Relationship between 28-day co mpressive strength (psi) and cement content at 17.5% design air content.............................................................99 4-12. Relationship between 28-day LBR strength and cement content............................99 4-13. Relationship between 28-day compressi ve strength (psi) and cement content.....100 4-14. Effect of mineral admixt ures on 28-day LBR strength.........................................101 4-15. Effect of mineral admixt ures on 56-day LBR strength.........................................102 4-16. Compressive strength (psi) of Type I/II vs. Type I cement for BM15..................103 4-17. LBR strength of Type I/II vs. Type I cement for BM15.......................................103 4-18. Compressive strength (psi) of Type I/II vs. Type I cement for BM 25.................103 4-19. LBR strength of Type I/II vs. Type I cement for BM 25......................................104

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xiv 4-20. Compressive strength (psi) of Type I/II vs. Type I cement for BM 48.................104 4-21. LBR strength of Type I/II vs. Type I cement for BM 48......................................104 4-22. Compressive strength (psi) of Type I/II vs. Type I cement for BM 54.................105 4-23. LBR strength of Type I/II vs. Type I cement for BM 54......................................105 4-24. Effect of w/c ratio on volume change....................................................................107 4-25. Effect of cement content on volume change.........................................................107 4-26. Effect of mineral ad mixtures on volume change...................................................108 4-27. Flow diameter vs. sand-to-water ratio...................................................................110 5-1. Residuals versus fitted values plot (28-day LBR)...................................................116 5-2. Residuals versus fitted values plot (28-day psi)......................................................117 5-3. Residuals versus fitted va lues plot (% volume change)..........................................117 5-4. Accelerated curing vs. 28day normal curing strength............................................123 5-5. Accelerated curing vs. 28-day normal curing strength for all mixtures..................126 5-6. Accelerated curing vs. 56-day normal curing strength for all mixtures..................126 5-7. Estimated 28-day LBR strength vs. cement content at fixed air (15%) and fixed 0% mineral admixture............................................................................130 5-8. Estimated 56-day LBR strength vs. cement content at fixed air (15%) and fixed 0% mineral admixture............................................................................130 5-9. Estimated 28-day compressive strength vs. cement content at fixed air (15%) and fixed 0% mineral admixture...................................................131 5-10. Estimated 28-day compressive strength vs. cement content at fixed air (15%) and fixed 0% mineral admixture...................................................131 5-11. Estimated volume change vs. cem ent content at fi xed air (15%) and fixed 0% mineral admixture...................................................................................132 5-12. Estimated 28-day LBR strength vs w/c ratio at fixed air (15%) and fixed 0% mineral admixture...................................................................................132 5-13. Estimated 56-day LBR strength vs w/c ratio at fixed air (15%) and fixed 0% mineral admixture...................................................................................133

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xv 5-14. Estimated 28-day compressive streng th vs. w/c ratio at fixed air (15%) and fixed 0% mineral admixture............................................................................133 5-15. Estimated 56-day compressive streng th vs. w/c ratio at fixed air (15%) and fixed 0% mineral admixture............................................................................134 5-16. Estimated volume change vs. w/c ratio at fixed air (15%) and fixed 0% mineral admixture...................................................................................134 5-17. Estimated 28-day LBR strength vs. cement content at fixed air (8%) and fixed 20% fly ash mineral admixture.....................................................................135 5-18. Estimated 56-day LBR strength vs. cement content at fixed air (8%) and fixed 20% fly ash mineral admixture.....................................................................135 5-19. Estimated 28-day compressive strength vs. cement content at fixed air (8%) and fixed 20% fly ash mineral admixture.......................................136 5-20. Estimated 56-day compressive strength vs. cement content at fixed air (8%) and fixed 20% fly ash mineral admixture.......................................136 5-21. Estimated volume change vs. cem ent content at fixed air (8%) and fixed 20% fly ash mineral admixture.....................................................................137 5-22. Estimated 28-day LBR strength vs. w/c ratio at fixed air (8%) and fixed 20% fly ash mineral admixture.....................................................................137 5-23. Estimated 56-day LBR strength vs. w/c ratio at fixed air (8%) and fixed 20% fly ash mineral admixture.....................................................................138 5-24. Estimated 28-day compressive streng th vs. w/c ratio at fixed air (8%) and fixed 20% fly ash mineral admixture..............................................................138 5-25. Estimated 56-day compressive streng th vs. w/c ratio at fixed air (8%) and fixed 20% fly ash mineral admixture..............................................................139 5-26. Estimated volume change vs. w/c ratio at fixed air (8%) and fixed 20% fly ash mineral admixture.....................................................................139 5-27. Estimated 28-day LBR strength vs. cement content at fixed air (10%) and fixed 50% ground granulated blastfurnace slag mineral admixture...............140 5-28. Estimated 56-day LBR strength vs. cement content at fixed air (10%) and fixed 50% ground granulated blastfurnace slag mineral admixture...............140 5-29. Estimated 28-day compressive strength vs. cement content at fixed air (10%) and fixed 50% ground granulated blastfurnace slag mineral admixture...............141

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xvi 5-30. Estimated 56-day compressive strength vs. cement content at fixed air (10%) and fixed 50% ground granulated blastfurnace slag mineral admixture...............141 5-31. Estimated volume change vs. cemen t content at fixed air (10%) and fixed 50% ground granulated blastfurnace slag mineral admixture.....................142 5-32. Estimated 28-day LBR strength vs. w/c ratio at fixed air (10%) and fixed 50% ground granulated blastfurnace slag mineral admixture.....................142 5-33. Estimated 56-day LBR strength vs. w/c ratio at fixed air (10%) and fixed 50% ground granulated blastfurnace slag mineral admixture.....................143 5-34. Estimated 28-day compressive strength vs. w/c ratio at fixed air (10%) and fixed 50% ground granulated blastfurnace slag mineral admixture.....................143 5-35. Estimated 56-day compressive strength vs. w/c ratio at fixed air (10%) and fixed 50% ground granulated blastfurnace slag mineral admixture.....................144 5-36. Estimated volume change vs. w/c ratio at fixed air (10%) and fixed 50% ground granulated blast-furn ace slag mineral admixture...............................144 5-37. Comparison of measured a nd predicted 28-days strength.....................................147 5-38. Comparison of estimated 28-da y compressive strength for Bhat, NCHRP, and dissertation models...........................................................................150 5-39. Comparison of estimated 28-da y compressive strength for NCHRP and dissertation models..........................................................................................150 5-40. Comparison of measured and pred icted 28-day LBR strength of validation mixtures of model...................................................................................................160 5-41. Comparison of measured and pred icted 28-day compressi ve strength of validation mixtures of model..................................................................................160 5-42. Comparison of measured and pred icted 28-day (oven) LBR strength of validation mixtures of model..................................................................................161

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xvii Abstract of Dissertation Pres ented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy ASSESSMENT OF DESIGN AND PROPERTIES FOR FLOWABLE FILL USAGE IN HIGHWAY PAVEMENT CONSTRUCTION FOR CONDITIONS IN FLORIDA By Webert Lovencin May 2007 Chair: Fazil T. Najafi Cochair: Mang Tia Major Department: Civil and Coastal Engineering Flowable fill, also known as controlled lo w-strength material (CLSM), is a self compacting cementitious material primarily used as a backfill in lieu of compacted soil. Flowable fill is an extremely versatile constr uction material that has been used in a wide variety of applications. There are two types of flowable fill, excavatable and nonexcavatable. An excavatable flowable f ill mixture is considered excavatable when the 28-day compressive strength is 100 psi. Nonexcavatable mixtures are mixes in which the minimum design strength is at 125 psi or gr eater. The ability to control and predict the strength and volume change (shrinkage) is an important aspect to consider when designing a flowable fill mixture. Vari ous studies have been conducted to better understand and predict quality c ontrol measures such as the strength and the occurrence of shrinkage in flowable fill.

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xviii The aim of this research was to vary components of excavatable flowable fill mixtures. A 4 3 2 3 factorial design (i.e., 4 levels of cement, 3 levels of mineral admixtures, 2 levels of air content, and 3 levels of water/cement ratio) was applied to evaluate the compressive strength, limerock b earing ratio (LBR) strength, and shrinkage. With this studys objective in mind, a tota l of 58 mixtures were selected from the factorial design matrix and batched in a labor atory. The strength of the mixtures was evaluated at 6 hours, 1 day, 2 days ov en cured, 3 days, 28 days and 56 days. Mathematical models were developed to predict the LBR, compressive strength, and volume change. An accelerated curing method, along with prediction models, was developed to help estimate long-term strength of flowable fill. Based on the performance of the statistical analysis it was found that the models developed from this study provided good correlations for estimating stre ngth and volume change of excavatable flowable fill mixture. Though the models were found to provide good correlations, the formula developed for estimating the volume change was found to be unacceptable for design application. This study provides a rati onal method for engineers to utilize when designing flowable fill mixture.

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1 CHAPTER 1 INTRODUCTION 1.1 Background The construction industry searches for the most cost and time efficient means for completing its projects. Many of these proj ects include cutting and backfilling trenches for structure and drainage pi pe installation. Often cutti ng and backfilling trenches disrupts major traffic arteries. Standard practice for backfilling trenches includes soil being placed in 6-inch lifts and compacted until a minimum density threshold is achieved. The soil tests required to set a nd verify the density threshold in the field require several days to complete. To help in this matter, newer forms of construction material have been introduced. The most common is called contro lled low strength ma terial (CLSM), also known as flowable fill. The use of flowable fill negates the need fo r placing the 6-inch lifts and eliminates the need for practically all tests, excluding a simple in-place soil test. Flowable fill is an extremely versatile cons truction material that has been used in a wide variety of applications. Among the many successful applications of flowable fill are slurried backfill for walls, culverts, pipe trenches, bridge abutments and retaining walls; backfill for abandoned underground structures (including mines) or tanks; and floating slab foundation for lightweight structures [ 1,2]. Flowable fill offers a number of advantages over conventional earthfill materi als that require controlled compaction in layers [2]. The advantages include ease of mixing and placement, the ability to flow into hard-to-reach places, and the self-leve ling characteristic of the fill.

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2 1.2 Problem Statement 1.2.1 Strength Flowable fill answers the need for a fill th at allows prompt return to traffic flow, does not settle, does not require vibrati on or other means of compaction, can be excavated, is fast to place, and safer than other forms of fill. One requirement typically encountered with flowable fill is the need to limit the maximum compressive strength [3]. This requirement is necessary in cases wh ere future excavation may be required for maintenance and repair of embedded utilities. To predict the longterm strength and the excavatability of flowable fill using conventional excavating equipment, many approaches are employed. One approach for pr edicting whether or not a flowable fill mix is excavatable is to devel op a correlation using its early age strength and long-term strength. For example, a mixture exhibiting strength that is less than 100 psi would be classified as being excavatable Mixtures resulting in stre ngths higher than 100 psi would be very difficult to excavate and w ould be termed nonexcavatable. According to Digiola and Brenda [4], the proper control of strength in flowable fill is an important criterion used to develop a mix design. Despite this known criterion, a review of literature shows few studies publishe d in proper control of strength in flowable fill. In using flowable fill, not only is it required to meet minimal strengths to maintain and provide suitable structural support, but the maximum strength development must also be controlled to allow for future excavation. A study by Pons et al. [3] shows that in 1994, about 80% of the concrete producer ma rket producing flowable fill carried the understanding or expectation for excavatabilit y. For these reasons, design strengths often must be assigned a range of strengths from minimally acceptable to maximum allowable.

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3 Many state agencies specify acceptance strengths at a curing age of 28 days, while others include 56-day strength in their specif ications [5]. In some cases, the maximum strengths are listed to enable excavation for a later date. Some state agencies, however, list the target strengths instead of maximum strengths which causes some concrete plants to produce flowable fill mixes with mini mum strength, as they would normally for Portland cement concrete. In general, the de sired strength is the maximum hardness that can be excavated at a later date using conve ntional excavating equipment. The existing Florida Department of Transportation (FDOT) flowable fill specification requires field tests to verify that a minimum pene tration resistance is achieved. Flowable fill mixtures are usually desi gned on the basis of compressive strength development. Little information is av ailable in which the terminology used for describing the strength of flowable fill is something other than compressive strength. This method of describing the quality of flowable fill is conve ntional throughout the ready mix industry. Because flowable fill is used as a backfill material similar to soil, a suitable unit instead of compre ssive strength, such as limer ock bearing ratio (LBR), is needed to describe the in-place bearing stre ngth of the flowable fill mixture. Making such a change would alter the state-of-the-a rt for relating the quality of strength for flowable fill mixtures. 1.2.2 Shrinkage To understand why shrinkage occurs, one mu st first understand the materials in flowable fill. Just as shrinkage occurs in concrete, it also occurs in flowable fill. Cement, a key ingredient in flowable fill, when mixed with water forms a paste and a chemical reaction called hydrat ion occurs. The hardened cement paste is what binds all the other ingredients together to create flowable fill.

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4 During the process of hydration, tiny voids filled with water a nd air form in the paste. The more porous the cement paste is in a mixture, the weaker the mixture. Studies have shown that voids in concrete play a vita l role in shrinkage. After pouring, concrete will change volume as moisture levels change. In flowable fill this phenomenon also takes place. Another condition playing a key role in concrete shrinkage is temperature. Expansion and shrinkage due to changes in te mperature can put stre ss on flowable fill, resulting in cracks. Studies have shown that hi gh water/cement (w/c) ratio and high water content are the two factors known to cause unwarranted drying-shrinkage in concrete. Although flowable fill has a higher w/c ratio and hi gher water content than concrete, studies on drying shrinkage have indicated that flowable fill exhibits shrinkage to a lesser extent than concrete. Typical reports of linear-shrinkage values on fl owable fill are in the range of 0.002 to 0.05 percent (6). These values are similar to concrete with low drying shrinkage. The shrinkage and expansion of flowable fill tend to continue varying throughout testing. A study by Grandham et al (7) found that the maximum shrinkage and expansion values of flowable fill we re generally less than the acceptable limit established for concrete (7). Since flowable fill is often placed underneath roadways as a road base, varying volume change is an important attribute to investigate. In various parts of Florida moisture is greatly abundant. Because this is so, when flowable fill is used in these areas, it is affected, forcing the flowable fill volume to alter. From the volume change activities, cracks are often created, leading to water seepage through the cracks causing

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5 roadbed damage and deficiencies in the road way. The final result may include pavement depressions or pavement humps. Various problems encountered while using flowable fill arise from the lack of documented procedures to measure or determ ine long-term strength for future excavation. Some areas that need further inve stigation and documentation are as follows: A practical method for designi ng flowable fill mixtures. A thorough investigation of the effect s of shrinkage in flowable fill. A developed flowable fill design method th at utilizes commonly used units for describing the strength of backfill material s, such as limerock bearing ratio (LBR) instead of compressive strength. A study identifying long-term performance of flowable fill, particularly how the plastic properties of flowable fill affect its long-term strength and excavatability. It is critical that research be conducted at this time give n there is a large number of roadway construction, maintenance, and reha bilitation projects taking place throughout Florida. 1.3 Hypothesis Several factors in flowable fill are found to be similar to those identified in concrete as a controlled measure for predicting streng th. The factors incl ude w/c ratio, cement content, fly ash content, a nd plastic properties. The fo llowing hypothetical questions may be asked: (1) Is it possible to get ta rget strength (100 LBR) for flowable fill if quantities of its mixture components are known? (2) If so, can vary ing the components of flowable fill mix help targ et strength and shrinkage? Laboratory experiments can be conducted to identify key compone nts to help lay a foundation for developing rational methods to approach development of flowable fill mixture design for construction. In addition, models can be developed to employ known

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6 component parameters to produce reliable re sults for predicting strength and field performance (i.e., shrinkage) of flowable fill. 1.4 Objectives The primary objectives of this research are as follows: Vary mixture components of flowable fill, to help predict strength using prediction models. Vary mixture components to predict shrinka ge in flowable fill using a prediction model. Develop mix design procedures utilizing fine aggregate materials commonly used for flowable fill in the state of Florida. Identify setting behavior of flowable fill. Provide recommendations wher e warranted from findings. 1.5 Scope This is a continuance of a preliminary study in which the key goal was to evaluate the performance of flowable fill in paveme nt sections using accelerated and nonaccelerated mixtures. Using knowledge acquired from the findings of the preliminary study, the scope of the current research will focus on developing strength pr ediction models that incorporate flowable fill mix pa rameters. It is critical to vary known components (i.e., air content, cementitious content, etc.) for establishing the framework and creating the database to use for prediction models. Thus, th is research will focus on the effects of the following: strength in LBR for flowable fill mixtures; and change in flowable fill volume due to shrinkage. 1.6 Importance of Research The proper control of strength development in flowable fill applications is an important criterion in developing a design mi xture. Very few studies have been

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7 published evaluating the long-term strength of fl owable fill in LBR. This research will help to develop mix design procedures for concrete producers using flowable fill and will benefit the constr uction industry. The volume changes due to sh rinkage are of considerab le importance. If the amount of volume change in flowable fill due to shrinkage is derivable, producers will be able to modify their mixes for obtaining optimal mixtures. Also, contractors can compensate as necessary. 1.7 Research Approach To meet the research obj ectives, this study was conduc ted utilizing the process categorized as tasks provided below. Task 1 Literature search: Examine existing ideas, theories and re sults published about flowable fill reviewing various propertie s affecting its mixtures Review work done on concrete and geotechnical engineering practices Review past and current flowable fill practices materials, design mixes, properties, and testing practi ces to measure performance. Task 2 Data collection: Prepare laboratory design mixtures Design the experiment for laboratory mixtures Use factorial design Vary mixture components (i.e., cement, fly ash/slag, and water/cement ratio) Prepare mixture proportions and samples Run small-scale design mixes obtained from the studys factorial design Obtain test results from all design mixes performed. Task 3 Data analysis: Analyze experimental results obtained fr om laboratory tests carefully to meet the objectives of the study. Task 4 Model development using empirical approach: Develop model using SAS and Minitab. Task 5 Model interpretation: Evaluate reliability and effectiveness of models.

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8 Task 6 Final dissertation writing process: After completing Tasks 1 through 5, prepar e a final report in the form of a dissertation to highlight the achievements and original contributions of the research. The flowchart presented in Figure 1-1 gives a schematic view of the laboratory task process to be conducted as part of the research. Figure 1-1. Laborator y task process Yes No Make modifications Run batch mixtures Attain target air content and plastic properties Are the analyzed results viable ? Randomly select mixtures Assessing the design and properties for controlled low strength materials (CLSM) usage in highway pavement Determine performance Develop model and framework

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9 1.8 Outline of the Dissertation This dissertation is comprise d of six chapters. A brief summary of each chapter is provided below. Chapter 1 describes the background, problem statement, hypothesis, objectives, scope, and importance of this research and the approach used to conduct the research. Chapter 2 presents a literature review of basic informati on relating to flowable fill. The review focuses on flowable fill technol ogy, current practices, strength development, and strength pr ediction models. Chapter 3 explains information pertaining to the materials and experimental testing program evaluated in the study. The method of preparation of the flowable fill mixtures, design mix selection, mixture proportions, te st specimens, testing procedure, testing equipment and testing procedures utili zed in this study are also presented. Chapter 4 provides the laboratory results of the flowable fill mixtures. Detailed discussions on the results are included, along with influencing strength factors affecting the long-term behavior of flowable fill. Chapter 5 discusses the results and statis tical analysis performed on the laboratory data. Models predicting strength and volum e change are provided. An accelerated strength testing method is presented for estima ting the long-term strength of flowable fill. Chapter 6 summarizes the research and its conclusions and offers recommendations for further research.

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10 CHAPTER 2 LITERATURE REVIEW 2.1 Introduction A comprehensive literature search was conducted to identify and examine existing publications dealing with th e following subject matter: strength set time cement; and admixtures. 2.2 Flowable Fill Technology 2.2.1 Introduction Flowable fill, also referred to as cont rolled low strength material (CLSM), is a relatively new technology whose use has grow n over the years. It describes a fill technology that is used in place of compacted back fill. Flowable fill is self-leveling with a consistency similar to pan cake batter; it can be placed with minimal effort and no vibration or tamping is required. Flowable fill, or CLSM, is a highly flowable cementitious slurry typically comprised of water, cement, fine aggregates and often fly ash and chemical admixtures, including air-entraining agents, foaming agents, and accelerators. Other names used for this material are flowable mortar and lean-mix backfill [8]. Flowable fill is defined by the AC I Committee 229 as a self compacting cementitious material that is in a flowable st ate at the time of placement and that has a specified compressive strength of 200 lb/in2 or less at 28 days [6, p. 56]. Flowable fill

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11 has a low cementitious content for reduced strength development, which makes future excavation a possibility. This mixture is capable of filling all voids in irregular excavations and hard-to-reach places (such as under and around pipes) and hardens in a matter of a few hours without the ne ed for compaction in layers. 2.2.2 Types of Flowable Fill There are a variety of CLSM types availabl e for various engineering purposes. The most obvious distinction between types is the possible need for future removal. Thus, the current FDOT specification divides flowab le fill into two main classes: (i) excavatable fill; and (ii) nonexcavatable fill. Controlled low strength material (CLS M) excavatability is dependent on many factors including binder streng th, binder density, aggregate quantity, aggregate gradation, and the excavating equipment used. The Na tional Ready Mixed Concrete Association (NRMCA) recommends that excavatable CL SM mixes have a 20+ psi compressive strength at 3 days, a 30+ psi compressive st rength at 28 days, and ultimate compressive strength less than 150 psi. Compliance with these r ecommendations is typically established with cylinder compre ssive strength tests [2]. 2.2.3 Advantages of Using Controlle d Low Strength Material (CLSM) There are various inherent advantages of using CLSM over compacted soil and granular backfills. Some of these are listed below [8]. 1. It has a fast setup time. 2. It hardens to a degree that precl udes any future trench settlement. 3. The extra cost for the material, compared to compacted backfill, is offset by the fact that it eliminates the costs for compaction and labor, reduces the manpower required for close inspection of the back fill operation, requires less trench width, and reduces the time period and cost s of public protection measures.

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12 4. There are no problems due to settlemen t, frost action, or localized zones of increased stiffness. 5. Flowable fill mix designs can be adjusted to meet specific fill requirements, thus making the fill more customized and efficient. 6. Flowable fill is stronger and more durabl e than compacted soil or granular fill. 7. During placement, soil backfills must be tested after each lift for sufficient compaction. Flowable fill self-compacts consistently and doe s not need this extensive field testing. 8. It allows fast return to use by traffic. 9. Flowable fill does not form voids during placement nor settle or rut under loading. 10. Since it reduces exposure to possible cave-ins, flowable fill provides a safer environment for workers. 11. It reduces equipment needs. 12. It makes storage unnecessary because readymix trucks deliver flowable fill to the jobsite in the qua ntities needed. 13. Flowable fill containing fly ash benefits the environment by making use of this industrial waste by-product. These benefits also include reduced labor and equipment costs ( due to self-leveling properties and absence of need for compaction), faster cons truction, and the ability to place material in confined spaces. The relatively low strength of CLSM is advantageous because it allows for future excavation, if re quired. Another advantage of CLSM is that it often contains by-product materials, such as fly ash and foundry sand, thereby reducing the demands on landfills, where these ma terials might otherwise be deposited. Despite these benefits and advantages over compacted fill, the use of CLSM is not currently as widespread as its potential might warrant. CLSM is somewhat a hybrid material; it is a cementitious material that be haves more like a compacted fill. As such, much of the information and discussions on its uses and benefits are lost between concrete materials engineering and geot echnical engineering. Although there is

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13 considerable literature available on the topi c, CLSM is often not given the level of attention it deserves by either group. 2.2.4 Engineering Characteristics of CLSM When a CLSM mixture is designed, a variet y of engineering parameters needs to be evaluated prior to, during, and after placemen t in the field. Optimum conditions for each parameter depend on the application. Typical ly, blends will be proportioned and the desired characteristics will be tested according to the appropriate standard procedures. Although not all parameters need to be evalua ted, the following are of major consequence to the effectiveness of the CLSM mixture [9]: 1. strength development 2. time of set 3. flowability and fluidity, or consistency of the mixture 4. permeability 5. consolidation characteristics 6. California bearing-ratio test; and 7. freeze-thaw durability. The performance criteria for flowable fills are outlined in ACI 229R-94. Flowable fill is a member of the family of grout ma terial. ACI Committee 229 calls it controlled low strength material, and does not consider it concrete. If it is anticipated or specified that the flowable lean-mix backfill may be excavated at some point in the future, the strength must be much lower than the 1200 psi that ACI uses as the upper limit for CLSM. The late-age strength of removable CL SM materials should be in the range of 30 to 150 psi as measured by compressi ve strength in cylinders [8]. 2.2.5 Uses of Flowable Fill CLSM is typically specified and used as compacted fill in various applications, especially for backfill, utility bedding, void fill and bridge approaches. Backfill includes applications such as backfilling walls, sewer trenches, bridge abutments, conduit

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14 trenches, pile excavations, and retaining walls. As structural fill, it is used in foundation subbase, subfooting, floor slab base, and pi pe bedding. Utility bedding applications involve the use of CLSM as a bedding materi al for pipes, electrica l and other types of utilities, and conduits. Void -filling applications include the filling of sewers, tunnel shafts, basements or other underground struct ures such as road base, mud jacking, subfooting, and floor slab base. CLSM is also used in bridge approaches, either as a subbase for the bridge approach slab or as b ackfill with other elements. Other uses of flowable fill include abandoned underground storage tanks, wells, abandoned utility company vaults, voids under pavement, se wers and manholes, and around muddy areas [8,10]. Conventional backfill in trenches and around small structures usually involves placement of aggregate material in thin laye rs with labor-intensive compaction. Poorly constructed backfill or lack of control of compaction often creates excessive settlement of the road surface and may produce unacceptable stre sses on buried utilities and structures. Use of CLSM removes the necessity for m echanical compaction with the associated safety hazards for workers. It can also provide more efficient placement and may permit reduced trench dimensions [10]. 2.2.6 Delivery and Placement of Flowable Fill CLSM can be delivered in ready-mix concre te trucks and placed easily by chute in a flowable condition directly into the cavity to be filled or into a pump for final placement. For efficient pumpi ng, some granular material is needed in the mixture [8]. CLSM can even be transported as a dry materi al in a dump truck. It can be proportioned to be self-leveling thus not requiring co mpaction, and so can be placed with minimal

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15 effort without vibration or tamping. It hardens and develops strength, and can be designed to meet specific strength criteria or density requirements. Precautions against the following need to be taken into account while working with flowable fill [8]: 1. Fluidized CLSM is a heavy material a nd during placement (prior to setting) will exert a high fluid pressure ag ainst any forms, embankment, or wall used to contain the fill. 2. Placement of flowable fill around and under tanks, pipes, or large containers such as swimming pools, can cause the container to fl oat or shift. 2.2.7 Limits Although CLSM mixtures provide numerous advantages compared to conventional earth backfilling, some limitations must be considered when these materials are used. Limitations include the following [11]: 1. Requires lighter-weight pipes to be anchored. 2. Needs to undergo confinement before setting. 3. May not allow higher-strength mixtures to be excavated. 4. Forms or pipes used must resist lateral pr essures (lateral pressu re is applied while in the fluid condition). 2.3 Specifications, Test Methods, and Practices 2.3.1 Introduction The Environmental Protection Agency (EPA ) recommends that procuring agencies use ACI229R-94 and the ASTM standards listed in Table 2-1 when purchasing flowable fill or contracting for construction that invol ves backfilling or other fill applications. More than 20 states have specifications for flowable fill containing coal fly ash. They include California, Colorado, Delaware, Florid a, Georgia, Illinois, Indiana, Kansas, Kentucky, Maryland, Massachusetts, Michigan Minnesota, Nebraska, New Hampshire,

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16 New Mexico, North Carolina, Ohio, Texas, Washington, West Virginia, and Wisconsin. The history of the current standard test me thods for CLSM is rather short but quite important [12]. Table 2-1. Current ASTM standards on c ontrolled low strength material (CLSM) ASTM Specification Number Title D 4832-02 Standard Test Method for Prepara tion and Testing of Controlled Low Strength Material (CLSM) Test Cylinders D 5971-01 (PS 30) Standard Practice for Sampling Freshly Mixed Controlled Low Strength Material D 6023-02 (PS 29) Standard Test Method for Unit Weight, Yield, Cement Content and Air Content (Gravimetric) of Controlle d Low Strength Material (CLSM) D 6024-02 (PS 31) Standard Test Method for Ball Drop on Controlled Low Strength Material (CLSM) to Determine Suitability for Load Application D 6103-97 (PS 28) Standard Test Method for Flow Cons istency of Controlled Low Strength Material One or more of the following ASTM test methods listed in Table 2-1 are used primarily as a quality measure during backf illing and construction in the following areas [8,12]: 1. SamplingObtaining samples of the flowable fill for control tests shall be in accordance with Practice D 5971. 2. Unit weight, yield (ASTM C 138) and ai r content (ASTM C 231)Determining the unit weight, yield, or air content of a flow able fill mixture sh all be in accordance with Test Method D 6023. 3. Flow consistencyMeasuring the flowability of the flowable fill mixture shall be in accordance with Test Method D 6103. 4. Compressive strengthPreparing compressi ve strength cylinders and testing the hardened material for compressive strength shall be in accordance with Test Method D 4832. In addition to comparing to specification requirements, the compressive strength can provide an i ndication of the reliability of the mix ingredients and proportions. 5. Load applicationDetermining when th e hardened mixture has become strong enough to support load, such as backfill or pavement, shall be done in accordance with Test Method D 6024 [5].

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17 6. Penetration resistanceTests such as ASTM C 403 may be useful in judging the setting and strength development up to a penetration resistance number of 4000 (roughly 100 psi compressi ve cylinder strength). 7. Density testsThese are not required si nce it becomes rigid after hardening. 8. Setting and early strengthThese may be im portant where equipment, traffic, or construction loads must be carried. Setting is judged by scraping off loose accumulations of water and fines on top and seeing how much force is necessary to cause an indentation in the material. ASTM C 403 penetration can be run to estimate bearing strength. 9. Flowability of the CLSMFlowability is important, so that the mixture will flow into place and consolidate. Many states have developed specifications governing the use of CLSM. In some cases, these are provisional. However, spec ifications differ from state to state, and moreover, a variety of different test methods are currently be ing used to define the same intended properties. This lack of conform ity, both on specifications and testing methods, has also hindered the proliferation of CLSM applications. There are also technical challenges that have served as obstacles to widespread CLSM use. For instance, it is often observed in the field that excessive long-term strength gain makes it difficult to excavate CLSM at later stages. This can be a significant problem that translates to added cost and labor. Other technical issues deserving attention are the compatibility of CLSM with different types of utilities and pipes, and the durability of CLSM subjected to freezing and thawing cycles [13]. 2.3.2 ASTM Standard Test Methods 2.3.2.1 Standard Test Method for Preparatio n and Testing of CLSM Test Cylinders (ASTM D 4832-02) Cylinders of CLSM are tested to dete rmine the compressive strength of the material. The cylinders are prepared by pour ing a representative sample into molds, curing them, removing the cylinders from the molds, and capping the cylinders for

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18 compression testing. The cylinders are then tested by machine to obtain compressive strengths by applying a load unt il the specimen fails. Dupl icate cylinders are required [14]. The compressive strength of a sp ecimen is calculated as follows: cP f A (2-1) where fc = compressive strength in pounds per square inch (lb/in2); P = maximum failure load attained during testing in pounds (lb); and A = load area of specimen in square inches (in2). This test is one of a series of quality control tests that can be performed on CLSM during construction to monitor complia nce with specification requirements. 2.3.2.2 Standard Practice for Sampling Fr eshly Mixed CLSM (ASTM D 5971-96) This practice explains the procedure for obtaining a representative sample of the freshly mixed flowable fill as delivered to the project site for control and properties tests. Tests for composite sample size shall be larg e enough to perform so as to ensure that a representative sample of the batch is take n. This includes sampli ng from revolving-drum truck mixers and from agitating equipment used to transport central-mixed CLSM [14]. 2.3.2.3 Standard Test Method for Unit We ight, Yield, Cement Content and Air Content (Gravimetric) of CLSM (ASTM D 6023-96) This practice explains the procedure for obtaining a representative sample of the freshly mixed flowable fill (as delivered). The density of the CLSM is determined by filling a measure with CLSM, determining the mass, calculating the volume of the measure, then dividing the mass by the volum e. The yield, cement content, and air content of the CLSM are calculated base d on the masses and volumes of the batch components [14].

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19 a) Yield: 1W Y W (2-2) where Y = volume of CLSM produced per batch in cubic feet (ft3); W = density of CLSM in pounds per cubic foot (lb/ft3); and W1 = total mass of all materials batched, lb. b) Cement content: tN N Y (2-3) where N = actual cement content in pounds per cubic yard (lb/yd3); Nt = mass of cement in the batch, lb; and Y = volume of CLSM produced per batch in cubic yards (yd3). c) Air content: 100 TW A T (2-4) where A = air content (percent of voids) in the CLSM; T = theoretical density of the CLSM computed on an air free basis, lb/ft3; and W = density of CLSM, lb/ft3. 2.3.2.4 Standard Test Method for Ball Drop on CLSM to Determine Suitability for Load Application (ASTM D 6024-96) This test method is used primarily as a fi eld test to determine the readiness of the CLSM to accept loads prior to adding a tempor ary or permanent wearing surface. A standard cylindrical weight is dropped five times from a specific height onto the surface of in-place CLSM. The diameter of the resulti ng indentation is measured and compared to established criteria. The indentation is insp ected for any free water brought to the surface from the impact [14].

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20 2.3.2.5 Standard Test Method for Flow Consistency of CLSM (ASTM D 6103-96) This test method determines the fluidity and consistency of fr esh CLSM mixtures for use as backfill or structural fill. It applies to flowable CLSM with a maximum particle size of 19.0 mm (3/4 in.) or less, or to the por tion of CLSM that passes a 19.0-mm sieve. An open-ended cylinder is placed on a flat, level surface and filled with fresh CLSM. The cylinder is raised quickly so the CLSM will flow into a patty. The average diameter of the patty is determined and compared to established criteria [14]. 2.3.3 Other Currently Used and Proposed Test Methods The American Concrete Institute (ACI) classifies CLSM as a mixture design having a maximum 28-day compressive strength of 1200 lb/in2. A CLSM mixture that is considered to be excavatable at a later ag e using hand tools should have a compressive strength lower than 101.5 psi at the 28-day stag e [14]. This is used to minimize the cost of excavating a mix at a later stage. Two field requirements that should be specified to ensure quality control and ease of placemen t are a minimum level of flowability or consistency and a specified method of measur ing it. Measuring fl owability utilizing the flow cone method is most appl icable for grout mixtures that use no aggregate filler. A maximum flow cone measurement of 35 seconds or a minimum slump of 9 in. would be two practical design parameters. Other methods to specify CLSM consistency have also been suggested. One such method is very similar to the ASTM standard test specification, Flow Table for Use in Test s of Hydraulic Cement (C 230), for determining the consistency or flow of mortar mixtures [14]. Permeability of the CLSM mixtures has been measured using the ASTM Test Method for Measurement of Hydraulic Conductiv ity of Saturated Porous Materials Using a Flexible Wall Permeameter (D 5084). Loss on ignition of CLSM mixtures, and

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21 mineralogy of the hardened CLSM has been determined on the basis of similar tests for cement. It has been determined that aggr egate containing up to 21% finer than 0.075 mm could be used to produce a flowable fill mix meeting National Ready Mixed Concrete Association (NRMCA) performa nce recommendations [14]. The gradation has been determined pe r ASTM C136-01, Standard Test Method for Sieve Analysis of Fine and Coarse A ggregates and ASTM C117, Standard Test Method for Materials Finer than 75 m (No. 200) Sieve in Mineral Aggregates by Washing. Also, AASHTO M43 #10 screening aggregate specifications [15] has been used to determine the suitability of utilizing th e compliance of aggregates used with these standards [14]. A new ASTM standard, Standard Practi ce for Installing Buried Pipe Using Flowable Fill has been proposed, which descri bes how to use flowable fill for installing buried pipe. ASTM Committee C 3 on Clay Pipe has already initiated mentioning the use of flowable fill in the Standard C 12 that covers installation of clay pipe [14]. A summarized overview of the test standa rds currently in use and that of provisional test methods is as follows [14]: Provisional methods of testing 1) AASHTO Designation: X7 (2001)Ev aluating the Corrosion Performance of Samples Embedded in Controlled Low Strength Material (CLSM) via Mass Loss Testing 2) AASHTO Designation: X8 (2001) Determining the Potential for Segregation in Controlled Low St rength Material (CLSM) Mixtures 3) AASHTO Designation: X9 (2001)Eval uating the Subsidence of Controlled Low Strength Materials (CLSM).

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22 Other ASTM test methods used in CLSM technology 1) ASTM C231-97Standard Test Met hod for Air Content of Freshly Mixed Concrete by the Pressure Method 2) ASTM C403/C 403M-99Standard Test Method for Time of Setting of Concrete Mixtures by Penetration Resistance 3) ASTM D560-96Standard Test Methods for Freezing and Thawing Compacted Soil-Cement Mixtures 4) ASTM D5084-90 (Reapproved 1997)S tandard Test Method for Measurement of Hydraulic Conductivity of Sa turated Porous Materials Using a Flexible Wall Permeameter 5) ASTM G51-95 (Reapproved 2000)St andard Test Method for Measuring pH of Soil for Use in Corrosion Testing. 2.3.4 Specifications by the State Departments of Transportation From a survey of six southeastern states (shown in Table 2-2) carried out by Riggs and Keck [12], it is apparent that all of the specifications were issued after 1990, and so the use of CLSM is relatively new to standa rd transportation road construction. Tables 2-3 and 2-4 show the comparison of similariti es and differences for various requirements based on the survey. Table 2-2. States surveyed and their specification on flowable fill State Specification and Title of Section Issue Date Alabama Section 260, Low Strength Cement Mortar 1996 Florida Section 121, Flowable Fill (revised 1996) 1997 Georgia Section 600, Controlled Low Strength Flowable Fill 1995 North Carolina Controlled Low Strength Material Specification 1996 South Carolina Specification 11, Specification for Flowable Fill 1992 Virginia Special Provisions for Flowable Backfill 1991 According to the survey, the general accep tance age is 28 days with two states having 56-day requirements (Table 2-3). As a result of the high levels of pozzolans in many CLSM mixtures, there can be significant st rength increases after 28 days. Several

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23 states have both excavatable and nonexcavat able mixtures. If the CLSM is to be removed at a later date, its strength must be limited to less than 300 psi, which can be assured only if later age st rengths are evaluated [12]. Table 2-3. Specified acceptance strengths and ages Strength, psi (MPa in parentheses) State Age (days) Minimum Maximum Alabama 28 80 (0.55) 200 (1.4) Florida 28 100 (0.7) 125 (0.9) Georgia 28 100 (0.7) 125 (0.9) North Carolina 28; 56 125 (0.9) 150 (1.0) South Carolina 28; 56 80 (0.55) 125 (0.86) Virginia 28 30 (0.2) 200 (1.4) Note: Maximum strengths are restricted to enab le excavation at later stages, if desired or needed. Table 2-4. Suggested mixture proportions, lb/yd3 (values in kilograms per cubic meter, kg/m3, are in parentheses) State Cement Pozzolan Fine Aggregate Water Air Range Alabama 61 (36) 185 (110) 195 (116) 195 (116) 517 (307) 331 (196) 0 572 (339) 572 (339) 0 2859 (1696) 2637 (1586) 2637 (1586) 2673 (1586) 413 (245) 509 (302) 500 (297) 488 (290) 488 (290) 341 (202) Not given Florida 75-100 (44-89) 75-150 (44-89) 0 150-600 (89-356) (a) (a) (b) (a) (b) 5-35 15-35 Georgia 75-100 (44-89) 75-150 (44-89) 0 150-600 (89-356) (a) (a) (b) (a) (b) 15-35 5-15 N. Carolina 40-100 (24-59) 100-150 (59-89) (a) (a) (a) (a) (b) (a) (b) 0-35 0-35 S. Carolina 50 (30) 50 (30) 600 (356) 600 (356) 2500 (1483) 2500 (1483) 458 (272) 541 (321) None (c) None (c) Virginia Contractor must submit his own mixture (mix design) Note: (a) Proportion to yield 1 yd3 (1 m3) (b) Proportion to produce proper consistency (c) Air up to 30% may be used if required.

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24 2.3.5 Use of Flowable Fill in the State of Florida Flowable fill has been used throughout the state of Florida as a construction material. The FDOT has used the material for bedding, encasements, tank enclosures, pipes, and general backfill for trenches. O ccasionally, the use of flowable fill has been specified for placement under a base with a set time of four hours or more prior to the placement of the base materials [16]. The current specification divides the flowable fill into two classes: excavatable and nonexcavatable. The maximum allowable 28-da y compressive strength of excavatable flowable fill is 100 psi. The minimum comp ressive strength for nonexcavatable flowable fill is 125 psi. The suggested range of cement and fly ash has been specified for each class of excavatable and nonexcav atable fill. Prior to use on projects, flowable fill mix designs must be approved by FDOT. The a pproval of the mix design is based on the specified range of material and laboratory te st data, such as air content, compressive strength, and unit weight [16]. 2.3.5.1 Material Specifications (Section 121-2) According to Section 121 of the FDOT Standard Specifications for Roadway and Bridge Construction, the material requirement s a flowable fill mix design must meet in order to be approved by FDOT are noted in Table 2-5 below [16]. Table 2-5. FDOT material s specificati on requirements Fine aggregatea...............................................................................Section 902 Portland cement (Types I, II, or III)................................................Section 921 Fly ash, slag and other pozzolanic materials................................. Section 929 Air-entraining admixturesb.............................................................Section 924 Water...............................................................................................Section 923 aAny clean fine aggregate with 100% passing a 3/8-in. (9.5-mm) mesh sieve and not more than 15% passing a No. 200 (75 m) sieve may be used. bHigh air generators or foaming agents may be used in lieu of conventional air-entraining admixtures and may be added at jobsite and mixed in accordance with manufacturers recommendation.

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25 All materials used should meet other sp ecification requirements on a consistent basis (see Section 2.3.5.3 below). 2.3.5.2 Construction Requirements and Acceptance (Section 121-5, 121-6) FDOT specifications require the am bient air temperature to be 40 F (4 C) or higher and the mix be deliver ed at a temperature of 50 F (10 C) or higher. FDOT does not permit placement during rain or when the temperature is below 40 F. Specification requires the material to remain undisturbed until it reaches a penetration resistance of 35 psi or higher. A soil penetrometer (ASTM C 403, Standard Test Method for Time of Setting of Concrete Mixtures by Penetration Resistance) is us ed to measure setting time [16]. 2.3.5.3 Guideline for Construction Requirements and Acceptance (Section 121-5, 121-6) To assist in designing a flowable fill mix, Section 121 of the specifications provides a guideline shown in Table 2-6 for one to use in preparing a mix design [16]. Table 2-6. FDOT flow able fill mix design Excavatable Nonexcavatable Cement, Type I 75-100 lb/yd3 (45-60 kg/m3) 75-150 lb/yd3 (45-90 kg/m3) Fly ash None 150-600 lb/yd3 (90-335 kg/m3) Water a a Airb 5-35% 5-15% 28-day compressive strengthb Maximum 100 psi (690 kPa) Minimum 125 psi (860 kPa) Unit weightb (wet) 90-110 lb/yd3 (1440-1760 kg/m3) 100-125 lb/yd3 (1600-2000 kg/m3) aMix design shall produce a consistency that w ill result in a flowable self-leveling product at a time of placement. bThe requirements for percent air, compressive strength and unit weight are for laboratory designs only and are not intended for jobsite acceptance requirements. Fine aggregate shall be proportioned to yield 1 yd3 (1 m3).

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26 2.4 Early Set and Strength Development 2.4.1 Introduction The early strength of flowable fill in a plastic state comes primarily from the friction of particles of its constituents. This theory originates from the behavior of particles in slurry flow, powder technology, and tribology (the sc ience and technology of interacting surfaces in relati ve motion and all related pr actices, including friction, lubrication, and wear). Although slurry fl ow does not have any cementing agents, an explanation of the role of particle friction in slurry is an important base to fully understanding the early streng th of flowable fill. The end of the plastic state is indicated by hydration of cement particles and the role of cohesion appears to begin in this stag e. The hydration process in flowable fill can be explained based on the chemical reaction of cement and fly ash in the concrete. 2.4.2 Behavior of Slurries The behavior of slurries as described by Kendall is similar to that of coulomb materials, with a flow stress dependent on the high friction between the solid grains [17]. Three simple tests were conducted by Kendall, a plastimeter test, an extrusion test, and a bubble collapse test. The resu lt was that the slurries be came unmoldable, nonextrudable or noncompactable when the solid grains in the slurry became frictionally locked together. However, this effect can be prev ented by addition of a polymer lubricant which reduces friction between the grains thereby improving slurry flow. According to an experiment by Kendall invol ving wet concrete slurry, if the slurry is truly plastic, then at a pressure equal to the yield pressure, one s foot would sink into the slurry (as in the Bingham model) [17]. In that expe riment, the foot did not sink because the cement grains under the foot were pushed together, experienced friction, and

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27 so resisted flow. However, when some polym er lubricant is mixed into the slurry, the friction between the grains is reduced and the foot does sink through the material. This is similar to the addition of fly ash particles in flowable fill. Reynolds, in 1885, conducted an experiment in which a rubber balloon was filled with sand and water. When the water was excessive, the material was plastic. However when water was withdrawn from the balloon, the material suddenl y became rigid or dilatant. The rigidity resulted from the higher friction of sand particles since the particles were pushed closer together, similar to the disappearance of bleeding water in CLSM. 2.4.3 Early Hydration of Cement Particles In the reaction between cement and water, setting is caused by a selective hydration of cement compounds. The two compounds firs t to react are tricalcium aluminate (C3A) and tricalcium silicate (C3S). However, the addition of gypsum delays the formation of calcium aluminate hydrate, and instead, ettringi te precipitates first from the reaction of C3A and gypsum, then calcium silicate hydrate (C-S-H) forms from the C3S reaction. Apart from the rapidity of formation of cr ystalline products, the development of film around cement grains and a mutual coagulati on of paste components have also been suggested as factors in th e development of setting. According to Jawed and Skalny, once th e nucleation and crystallization of hydration products end the dormant period, hydra tion is accelerated by the presence of fly ash [1]. Fly ash particles provide additiona l surfaces for the precip itation of the hydration products, which would otherwise be formed on the surface of the C3S and hinder its interaction with water. By this account, the jump in ear ly strength development in flowable fill would occur at th e end of the induction period.

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28 2.4.4 Influence of Water to the Hydration of Cement Popovic concluded that the primary factors that influence the times of setting of a given cement are curing temperature, water/cem ent (w/c) ratio, and fineness of cement [2,18]. The times required to set based on the w/c ratio are illustrated in Figure 2-1 below from Soroka [19]. This figure shows that the higher the w/ c ratio, the longer the time required to set up. However, this is only valid for a small range of w/c ratios, which is 0.25 to 0.85. 0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 0.000.200.400.600.80 w/c ratio, by weightTime of Setting (hrs) Initial Set Final Set Figure 2-1. Influence of water/cement (w/c) ratio on the setting of Portland cement paste [19] A study by Soroka shows that initially the w/c ratio does not significantly affect the rate of hydration as indicate d by the constant amount of water combined for all mixes with different w/c ratios [19]. Later, as the w/c ratio lowers, the rate of hydration decreases, indicated by the smaller amount of water combined in the reactions. Soroka stated that the lower the w/c ratio, the lowe r the degree of hydration and the average rate of hydration. Soroka suggested that this slower rate of hydrat ion may be attributed to the decrease in the space available for the hydration product at a lower w/c ratio.

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29 2.4.5 Effects of Set Accelerato r on Hydration of Cement In the case of calcium chloride accelerator, Rixom and Mailvaganam concluded that there is no chemi cal reaction between C3S or dicalcium silicate (C2S) with calcium chloride, although their rate of reaction is increased [20]. They added that calcium chloride does not react significantly with cem ent paste for a period of 2 to 6 hours after mixing, although rapid setting can occur in th is period. Formations of new hydration products between C3A, gypsum, and calcium chloride ma y be present. These hydration products influence the setting behavior of the mix and contribute to higher strength because more hydration products are formed. 2.4.6 Set Time In practice, knowledge of the rate of reaction is important because the rate determines the time of setting and hardening. The initial reaction must be slow enough to allow time for the flowable fill to be tran sported and placed. Once it has been placed, rapid hardening is desirable. In the setting of cement paste, Neville indicates that setting refers to a change from a flui d to a rigid state and hardeni ng refers to gain of strength [21]. Although during setting th e paste acquires some strengt h, for practical purposes it is convenient to distinguis h setting from hardening. Recently, only hardening time has been recognized. Some studies reported that hardening time refers to the time period re quired for flowable fill to go from a plastic state to a hardened state with sufficient stre ngth to sustain loading [21]. These studies also pointed out that the hardening proce ss is influenced by excess water leaving the mixture. Excess water leaving the mixture makes the aggregate particles come into surface contact and the mixture becomes rigid. Also, the cement content has a major influence on the hardening time.

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30 Some research reports that hardening tim e takes about 3 to 5 hours under normal conditions. In practice, the extent of harden ing is judged by the abil ity to withstand foot traffic without surface depression [21]. 2.4.7 Strength Development According to Diamond, the local packing of flocs of cement particles near surfaces of aggregates or other solids in concrete is poor, and much solution-filled space remains in the vicinity despite general consolidation of the concrete [ 22]. Concrete contains little, if any, bulk uninterrupted cement paste. Di amond pointed out that when water is mixed with cement, the formation of definite shel ls of hydration product around cement grains is the first micro structure devel opment. This occurs after se veral hours. The shells are typically of the order of 1 micron in thickne ss and are usually composed of C-S-H with some local areas rich in cal cium hydroxide (CH) and occasional inward or outward extensions of ettringite needles or thin calcium monos ulfate plates. A function of fly ash in flowable fill is to provide flowability and fill interparticle voids if sand is in the mixture. However, when fly ash reacts with cement and water, the micro structural development is affected. Shells are not only formed around the cement particles but also around fly ash grains. The sh ells become tied into a developing skeletal structure induced by the growth of the cemen t hydration product. The rate of shell development around the fly ash pa rticles varies with chemistr y and reactivity in the fly ash. With a fly ash that is low in calcium such as class F fly ash, the shell formation is followed by a slow reaction on the surface of the fly ash sphere inside the shell. According to Helmuth in 1987, there has been disagreement concerning the time the Pozzolanic reaction begins [23]. Some previous wo rkers reported no important reaction before 28 days but some reported very early reaction. Helmuth said that the

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31 reaction appears to begin at an early age, but it does not contribute strength until later. However, there are conflicting reports about the effect of fly ash in cement hydration. Some reports indicate an acceleration of C3S hydration, but Jawed and Skalny reported a pronounced delay of the main heat evolution peak of C3S in the presence of fly ash [1]. The same situation also occurred for C3A. 2.4.8 Use of Mineral Admixture (Fly Ash and Granulated Ground Blast Furnace Slag) in Flowable Fill A review of the relationship of fly ash a nd slag as an integral component of the flowable fill mixture was investigated. Bo th materials are considered to be mineral admixtures. 2.4.8.1 Fly ash Fly ash is a pozzolanic material. Pozzola n is defined as a si liceous or aluminosiliceous material that possesses little or no cementitious value. Fly ash is a powder residue that comes from the combustion of pul verized coal in elec tric power generating plants. Fly ash is primarily silicate glass containing silica alumina, iron, and calcium. The minor constituents are magnesium, sulfur, sodium, potassium, and carbon. According to research by Halverson et al ., fly ash is the term generally used to describe the ash and non-combustible minera ls that are released from coal during combustion and that fly up and out of the bo iler with the flue gases [24]. The main constituents in fly ash are oxides, sulfat es, phosphates, partially converted dehydrated silicates, and other inorganic particulate matter residue fr om coal combustion [25]. Physically, fly ash is made up of fine, powdery particles, which are predominantly spherical, solid or hollow, and generally in an amorphous state, although uncombusted carbon in fly ash is usually in the form of angular solid particles [26]. Fly ash has a

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32 specific gravity between 2.1 to 3.0 and a specific surface area ranging from 170 to 1000 m2/kg, as determined by the Blaine air permeability test. The Blaine air permeability test, in accordance to ASTM C 204, measures finene ss of a material based on its permeability to air under specified conditions. Chemical properties of fly ash are much less consistent than physical properties, as fly ash is an inherently variable material. Fly ash variability is due to widespread differences in inorganic chemical constituen ts of the source coal, methods of coal preparation, combustion conditions, furnace t ype, and the ash collection, handling, and storage conditions at each utility site [27]. Si nce utilities may not have all these factors in common, fly ash from different facilities is li kely to vary significantly. Even within one power plant, however, fly ash characteristic s can change greatly over time based on load and operating conditions over a 24-hour period [28]. Consequently, lack of fly ash consistency is a serious disadvantage in utilizing ash for extensive and economic beneficial uses. Despite the uncertainty and variability of fly ash properties, some ash characteristics can be correlated to the physical and ch emical characteristics of the fuel source, particularly coal. For example, bituminous coal fly ash is predominantly composed of silica, alumina, iron oxide, and calcium, as well as a variable amount of unburned carbon. On the other hand, sub-bituminous and lignite coal fly ashes exhi bit higher concentrations of calcium and magnesium oxide and lo wer amounts of silica and iron oxide. These coals also usually produce fly ash with lower ca rbon content than that of anthracite [26]. Fly ash color generally varies from tan to gray and black, as a direct function of the carbon content remaining in the ash [29]. As h from lignite or sub-bituminous coal is

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33 generally tan to beige in co lor, indicating a low carbon cont ent and the presence of lime or calcium. Bituminous coal fly ash contai ns higher unburned carbon and is therefore a shade of gray. Lighter tints of gray can indi cate higher quality ash [26]. Indicated by the fly ash color, the quantity of unburned carbon carried over from combustion into the fly ash is measured by the loss on ignition (LOI). High LOI valu es are undesirable, as they indicate that the combustion of the source coal is incomplete and raw material is being carried through to a waste stream rather than being utilized for energy production. LOI is also a significant chemical property of fly ash and serves as a primary indicator to whether the ash will make a suitable replacem ent for cement in concrete production. Fly ash used as a cement replacement is required by ASTM C618 to have below 6% carbon content, however, it is preferred to have at or below 3% carbon by members of the cement and concrete industry [30]. ASTM C618 groups pozzolanic material into three classes: N, F, and C. Class N refers to natural pozzolans, classes F and C di fferentiate fly ash of different chemical and physical properties. Class F is composed of ash produced from burning lignite or bituminous coal [31]. This class exhibits pozzolanic reactivity but seldom shows any self-cementitious behavior. Class F fly ash is also termed low calcium ash, as it contains less than 6% calcium oxide (CaO) wei ght. On the other hand, Class C fly ash is generated from burning lignite or sub-bituminous coal and typically has higher concentrations of CaO, generally above 15% by weight [28]. Class C fly ash also exhibits both pozzolanic and self-cementitious behavior. The function of fly ash in flowable fill is to provide flowability and to fill interparticle voids for sands in the mixture.

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34 2.4.8.2 Slag The full correct name for slag is ground gra nulated blast-furnace slag. In mixtures of flowable fill and concrete, slag is consid ered as a cementitious material that can set and harden in the presence of water. Slag is the heavy, coarse, granular, incombustible particles remaining in the bottom of coal-fired boilers [32]. Slag is ash, a residue from combustion in a dry-bottom furnace, consisting of fused ash particles with a size distribution typically between 75 m and 2 mm and a composition that depends heavily on the coal source [28]. Essentially, this product is a waste product from the blast furnace process for manufactur ing of steel and iron. Granulated blast-furnace slag particles have very porous surface textures th at create potential fo r deterioration during collection, storage, handling, and use [26]. It is primarily made up of silica, alumina, and iron, as well as low amounts of calcium, magnesium sulfates, and other inorganic materials [26]. The chemical characteristic s are derived from its coal source and not operating parameters. Based on its chemical co mposition and wide range of sizes, slag is not pozzolanic like fly ash, and therefore, ha s more limited applications in the cement and concrete industry [28]. Additionally, its corrosivity, conferred by high salt content and potentially low pH, limits its use in embankme nts, road base, subbase, or backfill, where potential contact with metal structures exists [26]. Slag is often used in the constructio n industry as a replacement for ordinary Portland cement. Since slag is a by-product of the iron production process and contains calcium silicates and aluminosilicates, its cementitious material has been touted for both its strength and durability-enhancing charac teristics when used in concrete. Ground granulated blast furnace slag also has a lower heat of hydration and, hence, generates less heat during concrete production and curing. As a result, slag is a desirable material to

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35 utilize in concrete placements where control of temperature is an issue. Percentage replacements by weight of slag fo r cement have ranged from 10 to 90%. During the early hydration of the slag, th e cement releases alkali metal ions and calcium hydroxides. The glassy slag st ructure is broken down and dissolved by the hydroxyl ions. Initially, the re action of the slag is with alkali hydroxide; later, the reaction is primarily with cal cium hydroxide [33]. As hydr ation continues long-term, the cement continues to precipitate calcium hydroxi de and grow rings of C-S-H inward from the original grain surface. Slag, on the othe r hand, develops more C-S-H, contributing to strength, density, and chemical resistance [34]. ASTM C 989 divides ground granulated bl ast-furnace slag into three strength grades in accordance with their Slag Activ ity Index (SAI) values: Grade 80, 100, and 120, with Grade 120 being the most active. Th e SAI is the ratio of the strength of a 50/50 blend of slag and cement to the strength of a plain cement mix at 7 and 28 days. The SAI is the criterion used for assessing the relative cementitious potential of slag [33]. However, the cement used as a reference mate rial must meet minimum requirements of compressive strength and alkali content. The cement used in a part icular project may be less reactive. In general, the early strengths of Grade 120 slag mixes are lower than other cement mixtures, but usually catch up and then surpass at 7 days and beyond. It is commonly believed that the other two grades ty pically exhibit lower strengths. Factors which affect slag mix performance and streng th development are as follows: 1) proportions of cementitious materials, 2) physical and chemical characteristics of the slag, 3) curing conditions, 4) presence and dosage rate of admixtures, 5) characteristics of the aggregate, and 6) characteristics of the cement.

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36 2.4.8.3 Difference between fly ash and slag Unlike fly ash which is a pozzolanic, gr anulated blast-furnace slag is self cementing. However, when it hydrates by itself, the amount of cementitious products formed and the rate of formation are insufficien t to give adequate strengths for structural applications. When slag is used in comb ination with Portland cement, the hydration of the slag is accelerated in the presence of calcium hydroxide and gypsum. The calcium hydroxide is also consumed by the slag in a pozzolanic reaction. Proportionally, slag chemical properties are contain more sulfur tr ioxide and sulfide sulf ur. Thus physically, slag and fly ash improve the stre ngth gain in flowable fill. 2.4.8.4 Specific applications Specific applications for both slag and fly ash vary. Both are used extensively in concrete and flowable fill mi xtures. Both materials help to improve the qualities of flowable fill. One of those qualities invol ves the workability of flowable fill. For specific applications involving void filling and backfilling of utility pipes, workability plays a vital role in flowability of mix and for the complete filling of utility trenches. 2.4.8.5 Mixture proportioning/mixture compliance According to the review of literature, th ere is no standard mixture proportioning adopted by the concrete industry involving mine ral admixtures for flowable fill. Many studies indicate the proportio ning of flowable fill is nor mally specified based on past experience and the availability of local materials. A key indicator on a construction jobsite for compliance in a mixture is accomplished through visual inspection of the mi xture. Excavatable and non-excavatable flowable fill are distinguis hable through mix texture. For example, non-excavatable

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37 mixes contain high amounts of cement and fly ash/slag. On the other hand, excavatable mixes typically contain low am ounts of cement and fly ash. 2.4.9 Effect of Moisture on Strength In concrete, most of the specifications requi re that it be maintained and tested in a saturated state. It has been found that dr y concrete has higher strength. Mindess and Young have indicated that the r easons are not completely unde rstood [35]. It is possibly due to the change in structure of the C-SH upon drying. Also, a change in internal friction and cohesion may cause a lubricating effect due to moisture allowing particles to more easily slip by each other in shear. In addition, the lower compressive strength of wet concrete may also occur b ecause of the development of internal pore pressures as a load is applied. According to Mindess and Young, the ease and extent of slip depends on the forces of attraction between pa rticles [35]. If the particles are chemically bonded, no slip can occur, but if only Van der Waals interactions ar e operating, slip is theoretically possible. It appears that measurable slip occurs onl y when sufficient thickness of water exists between the particles. The water can redu ce the Van der Waals forces sufficiently to allow slippage more readily; it can be t hought of as an analogy to lubrication. Soroka analyzed the decrease of compre ssive strength of cement paste based on Griffiths theory [19]. According to that theo ry, strength is expected to decrease with an increase in the moisture content of a mate rial because the presence of absorbed water reduces specific surface energy. Soroka added that another explanation of the decrease in strength is the decrease in cohesive forces which results from the presence of absorbed water. A decrease in the cohesive forces involves weaker bonds between particles.

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38 2.5 Strength Prediction Models 2.5.1 Introduction Past research done on flowable fill has focu sed on finding ways to better predict the long-term strength of flowable fill. This section reviews literature published regarding methods or models developed to pred ict the strength of flowable fill. 2.5.2 Hamilton CountyRemovability Index Specifications developed by Hamilton County, Ohio, and the City of Cincinnatis, Performance Specification for Trench Backfilling Consisting of the Use of Flowable Fill, uses the removability index for predicting long-term strength of flowable fill [36]. The removability index, used by Hamilton County, takes into consideration the dry unit weight ( w ) in conjunction with the 30-day compressive strength ( C ). Both are used to determine removability (excavatability) of a material. A flowable fill mixture is considered removable if the removability modulus ( RE ), calculated by the following equation, is equal to 1.0 or less. 1.540.5 610 1.0 10 wC RE (2-5) where w = dry unit weight (har dened material) (lb/ft3); and C = 30-day unconfined compressive strength (lb/in2). Table 2-7 below shows the removability modulus ( RE ) values for various combinations of compressive strengths ( C ) and unit weights ( w ) calculated by the above equation. This method of predicting long-te rm strength is depende nt on two variables, namely, unit weight and the 30day compressive strength.

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39 Table 2-7. Removability modulus ( RE ) Compressive Strength ( C ) (psi) w (lb/ft3) 25 50 75 100 125 150 175 200 50 0.18 0.26 0.32 0.37 0.41 0.45 0.49 0.52 70 0.30 0.43 0.53 0.61 0.68 0.75 0.81 0.86 90 0.44 0.63 0.77 0.89 0.99 1.09 1.17 1.26 110 0.60 0.85 1.04 1.20 1.34 1.47 1.59 1.70 130 0.77 1.09 1.33 1.54 1.72 1.89 2.04 2.18 150 0.96 1.35 1.65 1.91 2.14 2.34 2.53 2.70 Note: RE = 1.15 lb/in2 for hard clay RE = 1.00 lb/in2 for very stiff clay RE = 10.26 for 3000 lb/in2 Portland cement concrete Values in shaded area would not meet the material removability requirement 2.5.3 Bhats Study Some studies utilize parameters involved in mix design for predicting compressive strength for excavatability. A study by Bhat re lates the compressive strength of flowable fill with the mix w/c ratio [37]. Bhats equa tion shown below uses a single parameter for predicting strength at 28 days. 3126,905 374cS w c (2-6) where Sc = 28-day unconfined compressive strength (KPa); and w/c = water/cement ratio. According to Bhat, this model is able to correlate strength to w/c ratio (see Figure 2-2). Using Bhats equation, the wa ter cement ratios corre sponding to a 28-day compressive strength of 1035 KPa (150 psi) and 690 KPa (100 psi) are approximately 5.8 and 7.4, respectively. The resulting coefficient of determination (R-squared value, R2) is approximately 80%. This formula used only nonair-entrained flowab le fill mixtures when it was developed.

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40 0 100 200 300 400 500 600 051015 w/c ratio28-day Unconfined Compressive Strength, psi Figure 2-2. Bhats stre ngth prediction model 2.5.4 NCHRPStudy A study sponsored by the National Coope rative Highway Research Program (NCHRP), developed two models that predict compressive strength for flowable fill [38]. Equation 2-7, shown below, was developed for predicting strength for air-entrained mixtures. Equation 2-8 was developed for predicting strength for nonair-entrained mixtures. Prediction equation for ai r-entrained mixtures (/) bwc cfae (2-7) 0.31ln()0.23 at 0.01ln()0.27 bt where c f = compressive strength (Mpa); and t = age (days).

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41 Equation 2-7 was developed using high air c ontent mixtures. It uses w/c ratio as the predictive factor. Using this formula, one can predict the long-term strength gain (i.e., beyond a 91-day curing period). To improve the accuracy of Bhats equa tion, the NCHRP study developed Equation 2-8. Equation 2-8 incorporat es the following variables: 1. water/cement (w/c) ratio 2. aggregate type 3. fly ash type; and 4. fly ash content. Prediction equation for nonair-entrained mixture 124 3()()() () 0/btbtbt bt aggtypeflyashtypeflyashcontentStbtkkwck (2-8) where b0( t ) = 0.0007 t2 + 0.13 t 0.76 b1( t ) = 0.0001 t2 + 0.013 t 0.42 b2( t ) = 0.00008 t2 + 0.015 t 0.094 b3( t ) = 0.003 t 1.03 b4( t ) = 0.75 0.018 t when t 30 days b4( t ) = 0.22 when t > 30 days S ( t ) = compressive strength (Mpa); and t = age (days). The critical aspect to the approach of th e NCHRP model was to assign values to the nonnumerical variables used in the formula. Through a trial-and-error process, the following constants ( k ) were recommended for the materials used in the studys investigation. sand riverk = 1.0 sand foundryk = 0.2 ash bottomk = 1.0 ash Ck = 2.2 ash Fk = 1.0 ash HCk = 0.75

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42 Constants are assigned to aggregate t ype, fly ash type, and fly ash content variables. The empirical formula develope d by the NCHRP study is an equation that is readily available for one to use as a guide for designing flowable fill mixes. The formula employs the variables that are of si gnificance for predicting strength. 2.6 FDOT/UF Flowable Fill Study A study titled Use of Accelerated Flow able Fill in Pavement Section was conducted for the FDOT at the University of Florida (UF) investigating the usage of flowable fills in the pavement section [39]. The objective of that study was to evaluate performance of flowable fill in pavement se ctions using accelerated and nonaccelerated mixtures. This evaluation included determ ination of strength, set time, and flow applicable to conditions in Florida. The objective was accomplished by replicating approved FDOT flowable fill mixtures in a la boratory setting. A comprehensive review of the literature applicable to the research topics was conduc ted, followed by a survey of municipalities and counties regarding the use of flowable fill. The unit weight, air content, and compressive strength were anal yzed to establish th e conformity of the contractor-provided mixes and those produced in the lab to FDOT specifications. A relationship was revealed between the limer ock-bearing ratio (LBR) and penetrometer readings for different mix desi gns that will help measure the strength of underlying mix in the field. Unit weights of the mixes depi cted substantial variab ility amongst different mix designs as well as amongst different distri cts within the same mix design. However, a majority of the readings did not comply with FDOT specifications. Similar conclusions were drawn for the air content of different mi xes. The air content for a majority of the districts were not within the FDOT specifi ed range for both excavatable, as well as nonexcavatable design mixes. The strength of the flowable fill mixture performance in

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43 the laboratory and the strength obtained from collected samples of flowable fill from the field were evaluated. For the mixtures that were replicated in the laboratory and field samples being collected, the test yielded better insight and un derstanding of the compressive strength of flowable fill at va rious curing times. The compressive strength observed was typically above the FDOT specifi ed range for excavatable mixes. For the nonexcavatable mixes, the compressive st rength complied with FDOT specifications, however its value was considerably high. The relationship between LBR readings and penetrometer readings was established th rough regression models. The models were checked for adequacy. The previous flowable fill research was successfully completed; however, further research is necessary to yield a solution for producing flowable fill mixtures capable of being reproduced and replicat ed with state DOTs specifications. This research will concentrate on developing models for stre ngth and shrinkage prediction, and will establish a process, define procedures, and create guidelines for future flowable fill mixtures.

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44 CHAPTER 3 MATERIALS AND LABORATORY EXPERIMENTAL PROGRAM 3.1 Introduction This chapter describes detailed informati on pertaining to the materials and experimental design evaluated in this study. The method of preparation of the flowable fill mixtures, design mix selection, mix proportions fabrication of the test specimens and testing procedures used in this study are also presented. 3.2 Experimental Design The objective of this research was to evaluate flowable fill by varying mixture components to help predict 28-day strength us ing prediction models. This involves using excavatable flowable fill. 3.2.1 Rationale for Selecting Mixture Parameters To meet the research objectives, mixture pa rameters with ranges were reviewed and discussed. Particular interest was placed on evaluating parameters affecting flowable fill strength. Table 3-1 shows the parameters (factors) selected for designing the laboratory flowable fill mixtures. A factorial design was employe d to acquire insight into the effects of various mixture parameters on LBR, compressive stre ngth and shrinkage values of excavatable flowable fill material. Acco rding to Montgomery [40], the purpose of a factorial design is to study the effects of two or more factors. This is an experimental strategy in which factors are varied together, instead of one at a time. In general, factorial designs are most efficient for this type of experiment. By f actorial design, we mean that in each complete

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45 trial or replication of an expe riment, all possible combinations of the levels of the factors are investigated. For example, if there are a levels of factor A and b levels of factor B, each replicate contains all ab treatment combinations. The mixture parameters, provided in Table 3-1, include 4 factors. The factor s are cement content, air content, mineral admixtures, and water to cementitious (w/c) ra tio. The laboratory study consists of a 4 3 2 3 factorial design. This design su mmed up to a total of 144 mixtures including replicates. Table 3-1. Mixture parameters Mixture Parameters with Ranges Cement content (4 levels): 50 lb/yd3 100 lb/yd3 50 lb/yd3 200 lb/yd3 Air content (2 levels): 7.5 % 2.5% 17.5 % 2.5% Mineral admixtures (3 levels): No admixtures: 0% (1 level) Fly ash class F: 20% (1 level) Granulated ground blast furnace slag: 50% (1 level) w/c ratio (3 levels): 2.0 4.5 9.0 Slag: 50/50 or 50% slag and 50% Type I cement Fly ash class F: 20/80 or 20% slag and 80% Type I cement As seen in Table 3-1, the mineral admixt ures factor is varied at three levels, namely, 0%, 20% fly ash, and 50% slag. The 0% indicates a mix with no mineral admixtures, 20% fly ash indicates a mix cont aining a 80% cement to 20% fly ash ratio, and 50% slag indicates a 50% cement to 50% slag ratio. Appendix A provides the full factorial desi gn matrix along with tables showing the design of flowable fill batch mix combinations for the experiments. The tables show the order of the batches categorized into two experiments, Experi ment 1 and Experiment 2. Experiment 1 indicates the treatment combin ations and Experiment 2 represents the replicates. For each experiment, a to tal of 72 mixtures was generated.

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46 The order in which the flowable fill wa s batched involves the use of numerical randomization. According to Oehlert [41], randomization is one of the most important elements of a well-designed experiment. T ypically, the process of randomizing involves the usage of numbers taken from a table of random numbers or generated by a random number generator in computer soft ware. The random numbers obtained for the study were generated using computer softwa re. The spreadsheet software used was Microsoft Excel. Random numbers were genera ted for both experiments separately. After the numbers were obtained for each batch, they were then sorted into increasing order. 3.2.2 Mixture Proportioning The design procedure used in this res earch project was based on the Absolute Volume Method (SSD). Steps in the mixture design calculations are: 1. Calculate absolute volume of ceme nt in cubic feet per cubic yard (ft3/yd3 ) of flowable fill. 62.4w v cC C s (3-1) 2. Calculate absolute vo lume of fly ash in ft3/yd3 of flowable fill. 100 62.4p ww w v fF FC F F s (3-2)

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47 3. Calculate absolute volume of slag in ft3/yd3 of flowable fill. 100 62.4p ww w v sS SC S S s (3-3) 4. Calculate absolute volume of water in ft3/yd3 of flowable fill. 62.4w vW W (3-4) 5. Calculate absolute volu me of air content in ft3/yd3 of flowable fill. 27 100p vA A (3-5) 6. Calculate absolute volume of saturatedsurface-dry (SSD) for fine aggregate in ft3/yd3 of flowable fill. 27vsvvvvFACFWA (3-6) 7. Calculate weight of saturated-surface-dr y in pounds per yard (lb/yd) of flowable fill. 62.4wsvsagFAFAS (3-7) 8. Calculate weight of fine aggregate base on natural mo isture content in pounds per cubic yard (lb/yd3 ) of flowable fill. 1 1wnwsN FAFA L (3-8) 9 Correct the weight of water due to percentage of moisture difference in lb/yd3 of flowable fill. wswn wWFAFA WWW (3-9) where Cv = absolute volume of cement, ft3/yd3 Cw = weight of cement, lb/yd3

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48 Sc = specific gravity of cement Fw = weight of fly ash, lb/yd3 Fp = percent of fly ash by weight of cement Fv = absolute volume of fly ash, ft3/yd3 Sf = specific gravity of fly ash Sw = weight of slag, lb/yd3 Sp = percent of slag by weight of cement Sv = absolute volume of slag, ft3/yd3 Ss = specific gravity of slag Wv = absolute volume of actual water, ft3/yd3 Ww = weight of actual water, lb/yd3 Av = absolute volume of air, ft3/yd3 Ap = percent of air content FAvs = absolute volume of saturatedsurface-dry fine aggregate, ft3/yd3 FAws = weight of saturated-surf ace-dry fine aggregate, lb/ft3/yd3 Sag = specific gravity of aggregate FAwn = weight of fine aggregate base on natural moisture content, lb/yd3 N = percent of natural moisture content L = percent of absorption W = weight of water due to percentage of moisture different, lb/yd3; and W = water requirement, lb/yd3. Typical computations are presented in Appendix A. Appendix A also provides tables showing the volume comput ation results per combination of batch mix. The tables provide computation results for both 1 yd3 and 5.5 ft3 mix volumes. A sand-to-water ratio column is provided within the tables. The sand-to-water ratio was found beneficial throughout the research for help ing to determine whether a mixture is feasible or nonfeasible prior to mixing. Mixtures with a sand-to-water ratio range of 1.73 to 7.20 were deemed feasible and those out of that range were classified as non-feasible. This type of classification system was defi ned at the early stages of the research study through trial mixing and from the early pa rt of batch mixing. It was important to see whether a mix was feasible or non-feas ible for the purpose of time constraint.

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49 3.2.3 Specimen Sample Collection per Batch Mix The size and test samples to be collected from each batch are summarized below. Table 3-2 summarizes the overall specimen sa mples required for each batch mix. As shown, the total number of samples required fo r collection per mix is 33. The number of samples needed per mix and the type of specimen samples (i.e., 18 LBR and 15 plastic cylinder molds) helped determine the design of the experiment. The 33 samples collected per mix provided the basis for total volume of flowable fill needed for each mix. Table 3-2. Summary of sample specimens collected per mix Curing Period No. of Samples (LBR) No. of Samples (4-in. 8-in. cylinders) 6 hrs 3 -24 hrs 3 3 3 days 3 3 28 days 3 3 56 days 3 3 Oven cured, 2 days 3 -Total 18 15a Number of samples per mixtures = 33 Volume of each LBR mold = 169.65 in3 = 0.10 ft3 Volume of each 4 8 cylinders = 100.53 in3 = 0.0582 ft3 Volume of each 6 12 cylinders = 339.29 in3 = 0.1963 ft3 Total volume required to fill samples per batch mix: Volume = (18 169.65 + 12 100.53 + 3 339.29) in3 = 5277.93 in3 = 3.0544 ft3 aTotal includes three 6 12 cylinder samples produced for shrinkage testing. Table 3-2 also shows the curing durations used for all the samples collected per batch of mix. The volume of mix per batc h was based on the total number of samples needed per mix. As illustrated, an approximate volume of 3.0544 ft3 of flowable fill was determined to be the required amount per batch of mix. 3.2.4 Specimen Molds The specimen molds employed for the resear ch can be categorized as cylindrical LBR molds, either 4-in. 8-in. or 6-in. 12-in. test cylinders. The cylindrical LBR

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50 molds were used to carry flowable fill samples for LBR testing. Eighteen LBR molds were used in each batch mix. The mold samples were cured for varying periods: 6 hrs, 1 day, 2 days, 28 days, and 56 days. The test cylinders were of ASTM C 192-02 design. 3.2.5 Fabrication of Flowable Fill Specimens Each mix required several steps to be undertaken before specimens could be prepared. These are explained below. 3.2.5.1 Preparation of molds The test cylinder molds and the circular mo lds were always prepared two days prior to the start of the mix to be performed. The process of preparing for a mix required proper cleaning of each LBR mold, and greasing th em with mineral oil. The oil was used to help prevent the molded sample from stic king to the molds, after casting the flowable fill sample. This practice was necessary in or der to promote best practice and to reuse the molds after casting. A quart er-inch hole was drilled at the bottom end of each test cylinder. This was done, in order to allow fo r drainage of water from specimen samples. 3.2.5.2 Mixing of flowable fill All mixes were made during early morning hours. All flowable fill mixtures were prepared using an 8-ft3 rotating concrete mixer with a 42-i n. drum diameter. A picture of the mixer is shown in Figure 3-1. The mi xer is a 5.5-hp electric power mixer manufactured by Crown Equipment. The fo llowing procedures were followed: Two days prior to the start of each mix, all constituent materials (i.e., fine aggregate, cement, fly ash, ground blast furnace slag) were carefully weighted and placed into buckets with sealed lids. In addition, a 30-lb sample of fine aggregate was obtained and placed into a moisture-dryi ng oven to use for moisture correction. On the day of each mix, the moisture correction sample was removed from the oven, weighted and the result used for making the moisture correction to the weighted fine aggreg ates and water.

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51 Figure 3-1. Concrete mixer used in study The batching sequence consisted of pl acing the sand into the mixer and making sure that it was spread evenly inside the mi xer. After the fine aggregate was placed into the mixer, the mixer was turned on to homoge nize the fine aggregate, then 80% of the mixing water was added followed by the additi on of cement, and any other dry materials (i.e., fly ash, blast furnace slag). After pla cement of the dry materials into the mixer, the mixer was kept rotating for three minutes, fo llowed by a two-minute rest period. After the rest period, the remaining mixing wate r was added along with any required airentraining admixtures (AEA). The mixing was resumed for th ree additional minutes. At the end of the three minutes, a small sample of flowable fill was poured into a bin for measuring the target air content (see Figur e 3-2). The ASTM C 231 pressure method procedure was used. After testi ng the air content, if the mix did not satisfy the target air content, additional AEA would be added a nd the mix would be re-mixed for three additional minutes. At the end of the three mi nutes, another air test would be performed to check if the target air had been reached. This procedure would be repeated until the

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52 Figure 3-2. Pressure me ter test for air content target or acceptable level of air content wa s achieved. It was often found to be challenging to obtain both the desired air and water contents. For relatively dry flowable fill, adding AEA would increase the air content. For mixtures that were very fluid or had high flow, it was found to be very difficult to obtain 1 to 2% air content or air content near the target. The experience gained from trial mixing allowed more efficient converging to the target air content for each flowable fill mixture. Immediately after mixing, flowable fill was poured into a large bin container for transportation and subsequent transfer into specimen molds. Prior to pouring into specimen molds, a sample of the fresh mix was taken so that other plastic property measurements, such as unit weight, temperatur e, and flow tests coul d also be performed on the mix. Each specimen mold was properl y marked and labeled for identification and testing purposes.

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53 3.2.5.3 Casting of flowable fill The casting of the specimen molds, show n in Figures 3-3 through 3-5, involved placing them on a hard, flat and level surface. The surface used wa s a wooden palette. Placing the specimens on a wooden palette allowed for the specimens to be easily transported to a designated area for curing. Flowable fill was cast or poured into LBR specimens without the need fo r compaction, as is normally needed for testing soils. Casting the cylinder molds involve d placing the flowable fill in equal layers. Each layer was rodded and hand tapped to help release a ny trapped air. The same rodded and handtapped procedure was also applied to the LBR specimens. After the sample was filled, it was struck off with a tamping rod and the surf ace was troweled smooth. A plastic lid was placed on top of the specimen mo lds while excess flowable fill material was washed off the sides of the specimen and wooden palette. After specimens were collected, they were transported to a safe area, to be cured at room temperature without disturbance. Figure 3-3. Cast flowable fill in LBR samples

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54 Figure 3-4. Cast flowable fill in 4-in. 8-in. (compressive strength) samples Figure 3-5. Cast flowable fill in 6-in. 12-in. (volume change) samples

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55 The tests run on fresh flowable fill followed the ASTM standards shown in Table 2-1. These ASTM test methods are used prim arily as a quality meas ure. Temperature of the fresh flowable fill was determined in accordance with the ASTM C 1064 standard. This test was used to ensure that the temper ature of the fresh flowable fill was within normal range and to ensure no unexpected condi tions in the mix. A digital thermometer was used to monitor mix temper ature during plastic test. The measured plastic properties for each fl owable fill mixture are summarized in Tables 3-3 and 3-4, shown below. The result s of the mixtures are presented in the order in which they were batched. As previously specified, the order of the mix is based on their assigned random number. Note that mixtures marked with a superscript a represent mixtures batched for a third time due to equipment malfunctions during batching or testing. In Table 3-4 mixture numbers ending in R denote mixtures that were replicated for statistical purposes; mixt ures denoted with the term Type I are mixes batched using ASTM Type I Portland cement. 3.3 Limerock Bearing Ratio Te st (Florida Test Method 5-515) The Limerock Bearing Ratio (LBR) test wa s adopted by the Florida Department of Transportation (FDOT) as a standard strength test for subgrade and base materials in the 1960s [42]. The LBR test is a modified ve rsion of the California Bearing Ratio (CBR) test. This test defines the ability of a soil to support a load. As part of this test, the maximum density of the soil is determined by the standard ASTM D-1557 method. CBR was renamed LBR because the standard strength for the CBR test was changed to more closely represent Florida materials. Some mi nor procedural changes to the LBR test have also evolved over the years. The LBR test, as used in flexible pavement design in Florida, is a measure of the b earing capacity of soil. The test consists of measuring the

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56 Table 3-3. Properties of fresh flowable fill (Experiment 1) Air Content (%) Batch Mix Number AEAa (ml) Flow (in.) Target Achieved Unit Weight (lb/t3) Mixture Temperature ( F) 4 NR 4.25 7.5 2.5 22.00 100.80 68.00 25 NR 0.00 7.5 2.5 5.20 120.32 68.40 15 NR 0.00 7.5 2.5 7.60 121.04 70.00 23 NR 0.00 7.5 2.5 5.50 122.24 69.00 50 100 5.25 17.5 2.5 17.00 107.04 76.00 16 1600 4.25 7.5 2.5 1.30 126.80 71.00 61 200 6.50 17.5 2.5 20.00 103.28 70.00 34 500 4.50 7.5 2.5 1.00 124.76 70.00 24 1000 0.00 7.5 2.5 1.20 127.84 70.00 59 1000 6.00 17.5 2.5 4.80 125.92 72.00 58 100 5.50 17.5 2.5 18.00 111.52 73.00 51 1000 10.50 17.5 2.5 7.80 121.04 76.00 69 200 7.00 17.5 2.5 40.00 111.52 71.00 26 500 4.00 7.5 2.5 1.40 129.20 72.00 40 200 7.00 17.5 2.5 20.00 106.00 70.00 16b 500 7.00 7.5 2.5 0.80 132.08 72.00 14 10 0.00 7.5 2.5 15.00 112.24 72.00 8 250 5.00 7.5 2.5 21.00 103.12 78.00 30 500 0.00 7.5 2.5 2.00 128.08 71.00 18 25 0.00 7.5 2.5 13.00 114.24 70.00 20 500 0.00 7.5 2.5 0.60 129.52 72.00 44 75 5.50 17.5 2.5 15.20 111.60 79.00 65 75 8.00 17.5 2.5 15.00 110.16 76.00 54 25 0.00 17.5 2.5 16.00 109.84 78.00 55 500 7.00 17.5 2.5 7.40 124.24 78.00 12 25 0.00 7.5 2.5 15.00 110.08 78.00 22 25 0.00 7.5 2.5 18.00 106.72 77.00 33 25 0.00 7.5 2.5 18.50 107.84 73.10 19 500 9.00 7.5 2.5 4.50 125.44 73.20 48 175 6.75 17.5 2.5 25.00 106.64 73.00 4b 25 0.00 7.5 2.5 16.00 110.32 71.00 69b 25 4.25 17.5 2.5 17.00 115.44 70.50 Note: aNR = Not recorded bmixtures batched for a third time due to malfunctions during batching or testing

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57 Table 3-4. Properties of fresh flowable fill (Experiment 2) Air Content (%) Batch Mix Numbera AEAb (ml) Flow (in.) Target Achieved Unit Weight (lb/t3) Mixture Temperature ( F) 8R 250 7.50 7.5 2.5 24.50 99.92 70.00 16R 500 0.00 7.5 2.5 0.50 129.36 72.00 30R 500 0.00 7.5 2.5 2.00 129.12 72.00 18R NR 0.00 7.5 2.5 15.50 116.88 71.00 14R NR 0.00 7.5 2.5 13.00 116.88 75.00 22R NR 0.00 7.5 2.5 19.50 109.68 76.00 33R 25 0.00 7.5 2.5 17.50 107.44 76.00 23R 600 7.75 7.5 2.5 7.10 123.44 74.50 15-Type I 300 0.00 7.5 2.5 7.00 123.68 75.00 54-Type I 25 0.00 17.5 2.5 15.00 115.28 76.00 25-Type I 25 0.00 7.5 2.5 20.00 107.52 75.00 48-Type I 50 6.00 17.5 2.5 20.00 108.16 75.00 25R 25 0.00 7.5 2.5 17.00 108.24 75.00 34R 500 5.25 7.5 2.5 2.50 127.76 75.00 69R 50 6.00 17.5 2.5 20.00 105.12 74.00 26R 500 6.25 7.5 2.5 1.00 127.84 75.00 40R 125 6.50 17.5 2.5 24.00 102.40 79.00 19R 500 10.00 7.5 2.5 6.10 124.96 74.50 44R 75 5.00 17.5 2.5 18.00 108.72 78.00 48R 25 0.00 17.5 2.5 15.00 112.24 75.00 55R 500 8.50 17.5 2.5 3.20 128.88 75.00 54R NR 0.00 17.5 2.5 14.50 115.12 75.50 4R 25 0.00 7.5 2.5 15.00 117.04 75.00 58R 75 5.00 17.5 2.5 16.50 110.08 74.50 12R 25 0.00 7.5 2.5 12.00 117.52 75.00 15R 550 7.50 7.5 2.5 5.20 125.36 75.00 20R 500 0.00 7.5 2.5 1.10 127.6 75.00 65R 75 6.00 17.5 2.5 17.00 108.8 75.00 61R 150 8.50 17.5 2.5 21.00 101.76 76.00 59R 1000 9.00 17.5 2.5 6.30 123.52 78.00 51R 1000 7.50 17.5 2.5 8.00 120.24 71.00 24R 1000 6.50 7.5 2.5 1.70 127.76 69.00 50R 100 6.50 17.5 2.5 19.00 105.60 70.00 25Rc 25 0.00 7.5 2.5 17.00 108.72 70.00 48Rc 25 0.00 17.5 2.5 14.50 111.84 80.00 55Rc 500 5.50 17.5 2.5 5.70 123.12 75.00 Note: aR in mixture number = mixtures that were replicated for statistical purposes; Type I in mixture number = mixes batched using ASTM Type I Portland cement bNR = Not recorded cmixtures batched for a third time due to malfunctions during batching or testing

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58 load required to cause a standard circular plunger (an area of 3 in2) to penetrate the soil specimen at a specified rate (r efer to Figures 3-6 and 3-7) The specifications for the LBR test equipment are included in Table 3-5. The LBR test measures the unit load (in lb/in2) required to force the plunger into the soil 0.1 in., expresse d as a percentage of the unit load in lb/in2, required to force the same plunger to the same depth in a standard sample of crushed limerock. 10-lb seating load Magnetic clamp Penetration piston end area 3 sq. in. (1.95 in. dia. .01 in.) .001 in. indicating dial measuring penetration Surcharge weights (as required) Mold 6 in. internal dia. No. 4, 15-cm filter paper Soil sample 6 in. dia. 4.59 in. high Perforated base Figure 3-6. Cross section of s eated LBR penetra tion piston [42]

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59 Figure 3-7. LBR machine Table 3-5. Specifications for LBR test equipment Equipment Specifications LBR Press Rainhart Company, Model 762 Rate of loading: .050 in./minute Load cell capacity: 10,000 lbs LBR Recording Device GPE, Inc., Model DMP-12A Digital LBR readout Proprietary plot program RS 232 communications port Download to computer: Windows XP System Calibration Device Steel spring soil simulator at 100 LBR 5 LBR

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60 The average penetration unit load for a typical crushed limerock found in Florida has been standardized to 800 lb/in2. The resulting ratio multiplied by 100 is known as the Limerock Bearing Ratio (with percentage omitted). The test results are intended to provide the relative bearing value of base and stabilized materials [42]. Samples are tested by penetrating the speci mens. This is accomplished with an automatic compression device equipped with a lo ad measuring system. A typical test is shown and the penetration curve is plotted in Figures 3-8 and 3-9, respectively. The corrected unit load obtaine d at 0.1-inch penetration is divided by 800 lb/in2, the standard strength of limerock. This ratio is then multiplied by 100, and the resulting value is the LBR in percent, as shown in equation below. CorrectedUnitLoad LBR100 800 (3-10) The load penetration relationship curve will usually be c onvex upwards although the initial portion of the curve may be concave upwards. The concavity is assumed to be due to surface irregularities (F igure 3-9). A correction is ap plied by drawing a tangent to the curve at the point of greatest slope. The corrected curve then becomes the tangent plus the convex portion of the original curve with the origin moved to the point where the tangent intersects the horizontal axis. Methods of correcting ty pical curves are illustrated in Figures 3-8 and 3-9. 3.4 Compressive Strength Test Although there is an existing standard method for measuring the unconfined compressive strength of flowab le fill (ASTM D 4832), a diffe rent method was utilized for this research. Compressive strength test s were performed according to ASTM method D-2166-00 (AASHTO T 208-05). This test cove rs the determinati on of the unconfined

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61 Figure 3-8. Graph example showing typical load penetr ation curve that requires no correction [42]

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62 Figure 3-9. Graph example showing correcti on of typical load penetration curve for small surface irregularities [42]

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63 compressive strength of cohesive soil in the undisturbed, remolded, or compacted condition, using strain-controlled application of the axial load The test method provides an approximate value of the strength of cohesi ve soils in terms of total stresses. The method of testing was selected due to th e low strength of flowable fill and the resemblance of its properties to cohesive so ils. The compression tests were performed using a computerized testing machine with a relatively low-load capacity machine with displacement control. For this research the compression machine used was equipped with a 2000-lb load cell. The apparent strain rate was set at 0.015 inches per minute. The linear voltage displacement transducer (LVDT) used was a 2-inch MPE type HS. The load frame was a 5-ton compression mach ine, manufactured by Wykeham Farrance. Figure 3-10 shows the set up for the compressive strength test. The compressive strength of the test specimen is calcul ated by dividing the maximum load attained from the test by the cross-sectional ar ea of the specimen. Figure 3-10. Typical set-up fo r compressive strength test

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64 Before testing the flowable fill specimen, it was removed from its plastic cylinder mold. Removing the specimen from the mold involved careful handling due to its low strength (as compared to hardened concrete cylinders). The cylinders were cut lengthwise, using a box cutter. Specimens were ke pt in molds until the day of testing. 3.5 Proctor Penetrometer Test Penetration resistance of the LBR mold specimens were obtained using the proctor penetrometer testing method outlined in ASTM D 1558-99. In this test, a cylindrical needle tip is pressed one inch into the flowable fill at a constant rate, and the resistance offered by the flowable fill is measured in pounds. This value (in pounds) is divided by the cross sectional area of the tip in square inches, and is taken as the penetration resistance in pounds per square inch (psi). Si nce different needle tip diameters exist, the choice of needles selected depended on the streng th of the material being tested. Figure 3-11, shown below, depicts the proctor pene trometer device in its carrying case with a complete set of penetrometer needles. The needles have end areas of 1 in2, 3/4 in2, 1/2 in2, 1/3 in2, 1/5 in2, 1/10 in2, 1/20 in2, 1/30 in2, and 1/40 in2. The psi values obtained Figure 3-11. Typical proctor penetrometer

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65 from the proctor penetrometer are not equi valent to the psi va lues obtained from unconfined compressive strength tests. 3.6 Drying Oven A standard laboratory oven with approximately 6 ft3 of capacity was used for curing of oven specimen samples. LBR sample s were stored inside the oven at a set temperature of 110 F. The oven is equipped with a ther mostat and sensor to control the temperature of the oven. Prior to the start of ever y mix, the oven was turned on to ensure that it would be warm enough to place speci mens inside. Information acquired from specimens cured in the oven would help predict in-service aging. 3.7 Drying Shrinkage of Flowable Fill Mixtures For each flowable fill mixture batched, three 6-in. 12-in. cylinders were made to evaluate its shrinkage behavi or due to volume change. Th e cylinders were cured under normal conditions. Currently, no standard test methods exis t for the measurement of drying shrinkage in flowable fill. As a result, a review of published studies was done to identify standard methods of testing of drying shrinkage in fl owable fill. Most of the published studies reviewed showed the use of the conventiona l concrete method to measure shrinkage of flowable fill specimens (7). This method sp ecifies embedding gage st uds at both ends of a specimen and measuring the length change. Careful handling of the shrinkage prisms during form removal and subsequent measuremen ts is required. Flowable fill specimens could be damaged when using this approach because of the lower strengths of flowable fill. Thus, this approach may not be appropriate for flowable fill. Another approach found for measuring shrinkage in flowable f ill was used by Lutcht (43). In his study,

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66 Lutcht used the shrinkage ring method to measur e shrinkage in flowable fill. Typically, a shrinkage ring is used to measure the cracki ng of concrete cast around a steel ring. The approach utilized by Lutcht is not an adopted standard and thus represents 100% restraint and is used for assessing different material s and mixtures. Using the knowledge gained from other research studies, various attemp ts and methods were de vised to measure the volume change that occurs in flowable fill. 3.7.1 Method 1 The first method used to measure the dr ying shrinkage in flowable fill was somewhat similar to the ASTM C157 standa rds used for measuring drying free shrinkage in concrete. ASTM C157 standards call fo r using square prism specimen molds with dimensions of 3 3 11.25 inches. All of procedures of the ASTM C157 standards were followed, with the exception of the specim en molds. Instead of using square prism molds, 6-in. 12-in. cylinders were used. The amount of shrinkage was measured with a linear vol tage displacement transducer (LVDT) of an accuracy of 0.00039 in., which measured displacement. The LVDTs used for this project were made of AISI 400 series stainle ss steel. They are complete and ready-to-use displacement tr ansducers with a sleev e bearing structure on one end that supports a spring-loaded shaft att ached to the core. Th e bearing is threaded externally to facilitate mounting. By using a spring loaded LVDT, the need for core rods or core support structures is eliminated. All LVDTs are hermetically sealed to operate in harsh environments such as a moist room and have an operating temperature range of 0 F to 160 F ( 17.8 C to 71.1 C) to facilitate testing of temperature effects.

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67 The data acquisition system used wa s an Agilent 34970A unit (by Agilent Technologies) with a HP 34901A (20-channel armature multiplexer) plug-in module. The data acquisition unit can be set up to take readings at specified time intervals and for a specified length of time. The HP 34901A multiplexer module can read up to 20 channels of AC or DC volta ges with a maximum capacity of 300 V. It has a switching speed of up to 60 channels per second. It also has a built-in thermocouple reference junction for use in temperature measurement by means of thermocouples. Thus, the Agilent 34970A data acquisition unit with one HP 34901A multiplexer module will be adequate for the job of recording load a nd displacement readings from ten testing apparatuses. The Agilent 34970A unit can take up to three plug-in modules. Thus, if needed, it can be expanded to take up to 60 channels of output. The test setup for measuring the free shri nkage using LVDT is shown in Figures 3-12 and 3-13. Figure 3-12 is a photograph of several test set-ups that were used, simultaneously, while Figure 3-13 is the schemati c of these test set-ups. Three sets of measurements were taken from each specimen. A total of nine sets of measurements were taken from the three replicate specimens for each flowable fill mixture. Shrinkage measurements were taken at 1-, 3-, and 7-day intervals. The setup for the ASTM C157 free shrinka ge test consisted of a DC-powered LVDT connected to a shrinkage test frame that held the specimen. The output from the LVDT was connected to a Data Acquisition Sy stem (DAS). A laptop computer was used to download the data from the DAS. The da ta downloaded from the Data Acquisition System was in readable form with Microsof t Excel Comma Separated Variable format.

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68 Figure 3-12. Test set-up for measuring shrinkage using LVDTs Figure 3-13. Schematic of test set-up for measuring shrinkage using LVDTs

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69 3.7.2 Method 2 The second method for measuring drying shrinkage in the flowable fill specimen utilized a dial gauge. The process involved f illing the cylinder mold with flowable fill, finishing the surface, and then leveling it off w ith the cylinder top. This provided a 12-in. gauge length and 0.000-in. initial reading. Wh en the readings were taken, the plunger of the dial gauge was placed in the center of the cylinder and then lowered until the bridge set on top of the cylinder mold. A total of th ree readings were take n at 1-, 4-, and 7-day intervals. Figures 3-14 and 3-15 provide images of flowable fill specimen cylinders with the gauge being used. For this method, the gauge is used to measure the change in the specimen height which occurs as the flowab le fill specimen volume changes or shrinks (final height, hf, of flowable fill specimen). The dial gauge used has an accuracy reading Figure 3-14. Three-dial gauge reading me thod (gauge placed on level flowable fill surface)

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70 Figure 3-15. Dial gauge sh rinkage reading being taken of 0.00039 inch. After the final height of the flowable fill specimens was taken, the results were used to compute the percen t volume change by using Equation 3-11, % volume change 100if iVV V (3-11) where hi = initial specimen height hf = final specimen height Vi = initial volume Vi = area of specimen initial height of specimen = r2 hi Vf = final volume Vf = area of specimen final height of specimen = r2 hf 3.7.3 Method 3 The third method used for measuring sh rinkage involves measuring the height difference of the 4-in. 8-in. specimens. This method is more straightforward than the previous two and not much lab work is invol ved. The height difference is measured by subtracting the final specimen height (hf) from the initial specimen height (hi), as shown in the equation below. ifhhh (3-12)

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71 The final specimen height was measured after the flowable fill specimens were cured for 24 hours and demolded from the plastic cylinders. 3.8 Materials This section details information about the materials that were used in the preparation of mixes in the laboratory for this study. The materials used were adequately tested to ensure that they conformed to their manufacturers specifications. 3.8.1 Cement The cement used was Type I/II and Type I Portland cement. The Type I/II Portland cement is manufactured by Florida Rock Compa ny. The Type I cement is manufactured by Rinker Materials. Chemical and physical analyses of cements were conducted by FDOT State Materials personnel. The results can be seen in Tables 3-6 and 3-7. The cements procured met the specifications for Type I cement as given by C-114, C-109, C-151, C-187, C-204, and C-266. Table 3-6. Chemical composition of cement used Portland Cement Type Chemical Composition I (%) I/II (%) Loss of ignition (LOI) 1.40 1.90 Insoluble residue 0.13 0.40 Sulfur trioxide (SO3) 2.59 2.60 Magnesium oxide (MgO) 2.01 0.60 Tricalcium aluminate (Ca3Al) 4.02 7.00 Total alkali as (Na2O) 0.29 0.28 Silicon dioxide (SiO2) 20.91 21.20 Aluminum oxide (Al2O2 4.08 5.10 Ferric oxide (Fe2O3) 4.01 3.80 Tricalcium silicate (Ca3Si2) 62.29 50.00

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72 Table 3-7. Physical ch aracteristics of cement Compressive Strength Average (psi) Setting Time (Gilmore) (minutes) Type 3 Days 7 Days Fineness (m2/kg) Initial Final Soundness Autoclave Normal Consistency I 3310 4280 397 159 205 +0.03 % I/II 2720 3820 410 145 200 2720 3820 Table 3-6 provides the results of chemical analysis on the Portland cement used for the mixtures. According to the analysis, all cement met FDOT sp ecifications passing the required chemical analysis tests in order to be considered for use in FDOT concrete mix. 3.8.2 Fly Ash Strength of flowable fill can be improved by adding fly ash to the mixture. The fly ash acts to improve workability, and is a cementing agent that improves long-term strength. The silica glass in fly ash reacts with the free lime liberated during hydration of Portland cement to form a more stable cementing compound [44]. Fly ash was procured in a manner similar to that of cement. Class F fly ash was acquired from different manu facturers, which included JTM and others. The testing performed on the fly ash conforms to the re quired specifications fo r fly ash as given by C-114 and C-311 (see Table 3-8 for results). Th e Class F fly ash used had a unique color, light gray, very close to that of silica fume. 3.8.3 Blast Furnace Slag Ground blast furnace slag (ASTM C 989) was procured in a manner similar to the fly ash. Chemical and physical analyses we re carried out by FDOT State Materials personnel (see results in Table 3-9). Samples c onformed to required specifications C-989, C-114, C-109, and C-430.

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73 Table 3-8. Chemical and phys ical analyses of fly ash Parameter Value ASTM C 618 Class F Specifications Chemical Analysis: Sum of SiO2, Al2O3, & Fe2O3, % 84.20 min 70.0 Sulfur trioxide (SO3), % 1.00 max 5.0 Moisture content, % 0.10 max 3.0 Loss on ignition, % 4.90 max 6.0 Alkalis as Na2O equivalent, % max 1.5 Calcium oxide (CaO), % Physical Analysis: Fineness, amount retained on No. 325 sieve, % 29.00 max 34 Strength activity index7 days, % 66.00 min 75 Strength activity index28 days, % 81.00 min 75 Water requirement, % 98.00 max 105 Table 3-9. Chemical and physical analyses of blast furnace slag Parameter Value ASTM C 989 Grade 100 Specifications Chemical analysis: Sulfide sulfur (S), % 0.60 max 2.5 Sulfate ion reported as SO3, % 1.60 max 4.0 Physical analysis: Fineness, amount retained on No. 325 sieve, % 5.00 max 20 Air content, % max 12 Slag activity index days, % 108.00 min 90 Slag activity index days, % 142.00 min 110 Specific gravity 2.92 NA 3.8.4 Aggregates Procurement of aggregates was done in a manner similar to that of the cement. Table 3-10 provides information concerning th e location where fine aggregates were obtained. The fine aggregate used was sili ca sand. Throughout the study, two loads of sand were used. The first load is designated as sand #1 and the second load as sand #2.

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74 Table 3-10. Fine a ggregate location source Fine Aggregate Type Representative FDOT District FDOT Approved Aggregate Source Pit No. Location Silica sand 2 76-349 Melrose, Florida Both loads came from the same sand mine. Tests on the aggregates were performed according to ASTM and FDOT speci fications. The type of tests performed included the colorimetric and gradation tests. The colorimetric test was carried out to provide information on whether the aggregates contain impurities [21]. The tests were conducted in accordance to AASHTO T21 and AASHTO T71. Impurities interfere with the process of hydration of cement; coatings would prevent the development of a good bond between aggregate and the hydrated cemen t paste as well as other individual particles which are weak. The silica sand used in this study varied in color from light gray to sandy white. As specified by FDOT, the silica sands used we re composed of naturally occurring hard, strong, durable, uncoated grains of quartz and graded from coar se to fine. This type of sand is the same used for concrete mixes. 3.8.4.1 Aggregate gradation Gradation is perhaps the most important property of an aggr egate. It affects almost all the important properties for a mix, incl uding the relative aggr egate proportions, as well as the cement and water requirements, workability, pumpability, economy, porosity, shrinkage, and durability. Ther efore, gradation is a primary concern in concrete/flowable fill mix design. Aggregate gradation is the di stribution of particle sizes expressed as a percent of the total weight. The gradation as a percent of the total volume is also important, but expressing gradation as a pe rcent by weight is much easier and is a standard practice. Gradation analyses were performed on all fine aggregates used for all

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75 the mixtures created. The gradation was then compared using the ASTM and FDOTs upper limit (UL) and lower limit (LL) sieve anal ysis for fine aggregate as shown below in Table 3-11. ASTM and FDOT upper/lower lim its shall be graded within the limits indicated in Table 3-11. Table 3-11. ASTM C33-02A and FDOT speci fications for fine aggregate gradation Percent Passing Sieve Sizes ASTM C33 FDOT 9.50 mm (3/8 in.) 100 100 4.75 mm (No. 4) 95 to 100 95 to 100 2.36 mm (No. 8) 80 to 100 85 to 100 1.18 mm (No. 16) 50 to 85 65 to 97 600 m (No. 30) 25 to 60 25 to 70 300 m (No. 50) 5 to 30 5 to 35 75 m (No. 200) 0 to 10 4 Figure 3-16 illustrates the upper and lower li mits of the ASTM C33-02A gradation for fine aggregates. Figure 3-17 shows the gradation for fine aggregates in accordance with the FDOT fine aggregates specificati on. Unlike the ASTM C33-02A higher sieve 0 10 20 30 40 50 60 70 80 90 100 19.19.520.25 Sieve Sizes (mm)Percent Passing (%) ASTM LL ASTM UL sand #1 sand #2 Figure 3-16. Gradation of fine aggregatesASTM specs

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76 0 10 20 30 40 50 60 70 80 90 100 19.19.520.25 Sieve Sizes (mm)Percent Passing (%) FDOT LL FDOT UL sand #1 sand #2 Figure 3-17. Gradation of fine aggregatesFDOT specs gradation boundaries, the FDOT higher sieve gradation bound aries allow for both loads of sand to fall within the required specificati on gradation limits. Table 3-11 gives fine aggregate gradation variation that starts from sieve no. 16 down to sieve no. 200 between ASTM C33-02A and Florida specification. 3.8.4.2 Physical properties, absorption and moisture content The physical properties for the aggregates were provided by FDOT State Materials Geotechnical Laboratory. The phys ical properties for these a ggregates are summarized in Table 3-12. Table 3-12. Physical properties of fine aggregates (silica sand) Sand #1 Sand #2 Fineness modulus 2.23 2.05 Dry bulk specific gravity 2.63 2.62 Bulk specific gravity (SSD) 2.64 2.63 Apparent specific gravity 2.65 2.65 Absorption 0.44 = No data available

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77 Absorption is defined as the amount of water retained within the pores of the coarse or fine aggregate after saturation and re moval of the excess surface moisture. The aggregates were maintained in a saturate d condition and the mois ture content of the aggregates were determined regularly be fore casting, using ASTM C 566-97. The aggregate absorption was subtracted from the moisture content to yield the surface moisture, which was counted as part of the mixing water for the design mix. The actual weights of the wet aggregates and water us ed were determined using Equation 3-9. 3.8.4.3 Storage of fine aggregates As fine aggregates were obt ained from their aggregate source location, they were brought to the lab facility where mix was prep ared and stored in an area designated for aggregate storage. The photograph shown in Figure 3-18 depicts the area where the fine aggregates were stored prior to being used in a mix. Figure 3-18. Storage and removal of fine aggregates

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78 3.8.5 Admixtures The admixtures used were air-entraining ad mixture (AEA). It is classified as a Darex AEA, and manufactured by W.R. Grace & Co. Darex AEA is a liquid used as an air-entraining admixture, providing freeze/thaw du rability. It contains a catalyst used for forming a rapid and complete hydration of Po rtland cement. As it imparts workability into the mix, Darex AEA is particularly eff ective with slag, lightwe ight, or manufactured aggregates. The AEA used meets all the requirements of ASTM C494. 3.8.6 Water According to Kosmatka and Panarese, the presence of excessive impurities in mixing water is known to affect strength and dur ability of Portland cement concrete (44). It is believed that concrete and other cementitious mixtures containing mixing water having high levels of impurities may impact st rength development. In this study, potable water is used as mixing water for production of the flowable fill mixtures.

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79 CHAPTER 4 LABORATORY RESULTS AND DISCUSSIONS 4.1 Introduction This chapter presents the laboratory resu lts of the flowable fill mixtures. The laboratory tests were conducte d at the Florida Department of Transportation State Materials Office in Gainesville, Florida. De tailed discussions on th e results are included, along with influencing strength factors affecti ng the long-term behavior of flowable fill. In Chapter 5, a comprehensive statistical analysis of all data is discussed. 4.2 Laboratory Results 4.2.1 Limerock Bearing Ratio (LBR) Tables 4-1 and 4-2 provide the LBR resu lts for the mixtures performed in the laboratory for Experiments 1 and 2. LBR re sults are shown for 6-hour, 1-, 3-, 28and 56-day durations. The data shown were found to be repeatable in comparison to their low coefficient of variation values. From the tabl es it can be seen that no clear pattern exists among the individual batch mixes. Statistical analyses of the LBR results are presented in Chapter 5. 4.2.2 Compressive Strength (psi) The compressive strength results along with mixture proportions are shown in Tables 4-3 and 4-4 for each laboratory experi ment. Strength results are provided for 1-, 3-, 28and 56-day durations. Like the LBR data, the compressive strength results were found to be repeatable. The coefficients of variation for data obtained for both experiments range from 0% to 45.69%.

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80 Table 4-1. LBR strength results for Experiment #1 Batch Mix Number 6-hr Strength (LBR) Coeff. of Var. (%) 1-day Strength (LBR) Coeff. of Var. (%) 3-day Strength (LBR) Coeff. of Var. (%) 28-day Strength (LBR) Coeff. of Var. (%) 56-day Strength (LBR) Coeff. of Var. (%) 4 0 -1 0.00 10 11.18 52 7.72 49 10.80 25 1 0.00 6 39.74 15 20.96 45 33.68 70 14.50 15 1 0.00 22 47.24 37 19.49 140 12.88 200 19.03 23 3 0.00 14 4.23 34 21.86 148 6.01 223 32.88 50 0 -4 15.75 10 11.18 56 14.17 62 6.14 16 0 -33 5.25 75 4.81 242 16.36 337 13.50 61 0 -1 0.00 3 0.00 17 9.09 15 35.28 34 1 0.00 5 47.30 18 33.71 103 15.59 117 11.35 24 1 0.00 14 21.43 28 8.15 190 13.03 266 22.89 59 0 -10 31.11 31 38.21 230 33.90 270 23.76 58 0 -2 49.49 12 9.36 77 32.21 81 6.12 51 0 -28 32.79 35 9.27 219 44.51 190 4.56 69 0 -8 24.98 1 0.00 6 18.23 6 9.12 26 1 0.00 7 37.80 25 0.00 110 14.25 126 8.83 40 1 0.00 23 11.27 42 7.48 142 9.82 118 2.07 16 a 2 0.00 32 0.00 53 9.74 281 11.95 223 4.35 14 1 0.00 13 11.15 28 18.91 90 14.76 80 16.56 8 1 0.00 17 8.81 39 2.56 120 4.41 123 7.79 30 1 0.00 13 12.00 24 23.37 67 14.88 110 26.83 18 1 0.00 8 24.98 21 22.15 81 9.30 99 13.14 20 1 0.00 24 18.79 55 29.22 131 30.27 192 4.45 44 1 0.00 18 3.15 38 4.56 112 5.06 142 8.14 65 0 -2 0.00 3 33.33 12 9.90 16 16.54 54 1 0.00 7 7.87 18 5.56 36 30.24 73 28.68 55 0 -21 42.01 43 32.81 123 20.74 220 29.16 12 2 0.00 14 8.45 44 30.29 188 7.16 237 4.66 22 1 0.00 4 25.00 12 9.36 60 8.27 81 14.48 33 1 0.00 3 17.32 5 20.00 21 20.76 31 10.48 19 1 11.93 20 12.80 31 11.45 111 3.74 198 34.18 48 0 -6 16.67 35 11.66 173 30.65 173 17.67 4a 1 0.00 20 17.27 49 1.19 192 24.02 168 2.98 69a 1 0.00 2 0.00 6 20.38 32 8.27 35 6.54 Note: amixtures batched for a third time due to malfunctions during batching or testing

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81 Table 4-2. LBR strength results for Experiment #2 Batch Mix Numbera 6-hr Strength (LBR) Coeff. of Var. (%) 1-day Strength (LBR) Coeff. of Var. (%) 3-day Strength (LBR) Coeff. of Var. (%) 28-day Strength (LBR) Coeff. of Var. (%) 56-day Strength (LBR) Coeff. of Var. (%) 8r 0 -8 15.06 14 10.66 58 21.96 68 2.26 16r 0 -45 15.73 71 14.18 268 27.11 290 26.18 30r 2 0.00 10 24.35 22 18.65 55 15.56 122 2.87 18r 1 0.00 8 37.65 14 28.20 40 6.61 53 19.97 14r 2 0.00 9 22.30 17 31.77 50 30.54 79 24.05 22r 1 0.00 7 14.29 13 4.56 53 9.44 74 4.68 33r 1 5.06 3 43.30 7 17.32 34 7.29 38 10.54 23r 1 0.00 13 26.65 41 4.88 156 8.52 226 15.08 15-Type I 3 33.30 36 9.67 71 4.09 145 5.39 205 18.02 54-Type I 2 34.60 10 5.59 32 1.82 57 3.51 109 11.73 25-Type I 1 0.00 6 9.12 11 10.83 30 10.07 32 6.57 48-Type I 0 -17 6.66 55 8.54 173 1.33 190 2.90 25r 1 0.00 5 12.37 10 14.78 26 15.75 30 7.61 34r 0 -12 13.09 23 34.51 87 13.37 114 12.70 69r 0 -2 34.64 4 15.75 15 13.33 14 10.66 26r 2 0.00 23 21.57 49 37.40 101 39.46 153 20.09 40r 1 0.00 23 15.49 46 6.52 121 8.63 123 14.84 19r 2 2.47 24 12.20 52 13.56 117 12.64 152 10.67 44r 1 19.38 32 6.25 53 16.15 161 4.03 175 1.19 48r 1 0.00 28 16.30 70 2.86 254 3.16 282 2.36 55r 1 0.00 18 24.60 39 17.77 164 9.86 162 8.64 54r 1 0.00 16 9.35 25 9.93 52 17.13 112 3.09 4r 2 0.00 39 16.81 113 19.04 202 26.41 245 25.66 58r 0 -3 17.32 12 9.90 42 4.12 44 7.92 12r 3 21.65 23 12.74 61 16.15 242 12.20 216 14.31 15r 2 0.00 29 10.07 59 25.08 184 1.96 212 6.39 20r 1 0.00 35 26.21 57 16.21 143 32.23 238 23.94 65r 0 -3 43.30 5 12.37 16 16.54 14 0.00 61r 0 -2 34.64 3 33.00 12 24.74 12 26.06 59r 0 -9 16.37 19 18.23 151 24.43 181 20.89 51r 1 0.00 18 19.25 46 8.17 181 13.61 205 16.82 24r 0 -12 17.84 32 14.32 207 9.55 263 32.01 50r 0 -4 25.00 13 8.66 42 11.84 47 9.66 25rb 1 0.00 4 13.32 8 27.71 19 19.58 36 8.09 48rb 1 0.00 15 10.42 50 9.93 225 5.64 261 10.51 55rb 0 -15 16.41 44 12.61 158 5.87 189 29.93 Note: ar = mixtures that were replicated for statistical purposes; and Type I = mixtures batched using ASTM Type I Portland cement bmixtures batched for a third time due to malfunctions during batching or testing

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82 Table 4-3. Compressive streng th results for Experiment #1 Batch Mix Number 1-day Strength (psi) Coeff. of Var. (%) 3-day Strength (psi) Coeff. of Var. (%) 28-day Strength (psi) Coeff. of Var. (%) 56-day Strength (psi) Coeff. of Var. (%) 4 2 7.90 6 21.19 50 4.23 41 14.69 25 2 0.00 4 24.06 17 15.90 29 5.15 15 4 1.43 13 22.87 58 3.93 93 10.18 23 2 6.38 11 3.81 80 19.56 124 7.74 50 3 4.82 7 7.05 45 9.39 39 3.34 16 6 0.00 19 1.31 89 13.49 133 10.01 61 1 0.00 2 10.59 14 16.26 17 26.19 34 2 3.27 3 35.25 30 14.55 44 9.25 24 2 4.35 8 25.75 79 23.01 155 9.28 59 2 7.16 9 19.32 89 9.03 111 9.02 58 1 3.94 6 6.13 66 5.73 72 6.62 51 2 5.59 15 18.63 67 12.98 108 17.85 69 1 0.00 1 17.84 9 17.78 8 18.39 26 2 0.00 7 0.00 22 0.00 34 15.17 40 10 2.67 32 3.29 138 7.42 114 9.67 16 a 6 0.00 12 0.00 70 7.96 148 7.58 14 2 18.18 8 15.02 58 16.72 69 15.08 8 8 12.08 32 4.76 100 13.40 129 6.02 30 1 18.41 1 0.00 14 22.57 34 18.22 18 2 20.00 5 12.92 33 15.45 43 7.36 20 4 13.12 11 15.84 86 21.76 132 43.98 44 5 25.56 22 5.48 107 1.16 114 9.67 65 1 0.00 1 0.00 3 20.03 8 18.97 54 3 28.67 6 21.31 39 3.80 46 11.64 55 4 7.28 10 0.00 81 2.60 81 38.04 12 13 36.82 34 8.28 143 10.79 139 5.99 22 4 16.22 7 15.15 42 9.38 37 11.47 33 1 15.75 2 27.78 13 11.44 15 14.48 19 5 31.66 16 13.60 56 15.92 132 43.98 48 9 7.84 40 17.95 109 11.96 135 7.77 4a 14 12.70 34 3.25 115 4.09 105 14.86 69a 1 0.00 4 10.26 19 7.77 24 10.88 Note: amixtures batched for a third time due to malfunctions during batching or testing

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83 Table 4-4. Compressive streng th results for Experiment #2 Batch Mix Numbera 1-day Strength (psi) Coeff. of Var. (%) 3-day Strength (psi) Coeff. of Var. (%) 28-day Strength (psi) Coeff. of Var. (%) 56-day Strength (psi) Coeff. of Var. (%) 8r 5 13.56 19 9.31 63 3.05 57 4.55 16r 5 0.00 140 15.49 64 2.38 132 16.31 30r 1 18.41 5 43.75 18 27.25 38 23.22 18r 5 6.12 9 20.43 35 6.28 37 5.85 14r 5 8.66 12 12.07 40 11.23 65 12.93 22r 3 12.85 8 17.28 38 34.22 51 9.08 33r 1 17.84 3 1.88 15 10.14 18 8.56 23r 3 13.62 10 17.71 74 7.21 127 18.33 15-Type I 12 1.64 17 15.54 62 20.96 101 13.80 54-Type I 5 29.46 11 13.64 33 6.66 67 45.69 25-Type I 2 5.68 5 11.57 15 24.81 16 6.96 48-Type I 11 7.57 57 22.57 143 1.27 139 5.73 25r 2 15.10 4 16.44 8 0.00 15 8.26 34r 2 3.27 11 31.15 31 12.68 51 18.13 69r 1 0.00 4 23.20 15 18.13 14 20.00 26r 2 0.00 7 0.00 21 7.53 47 33.73 40r 23 9.54 49 10.69 151 2.43 131 0.84 19r 4 15.79 13 0.39 40 7.90 129 32.28 44r 17 8.82 36 10.33 139 5.11 131 0.84 48r 17 8.32 49. 1.42 162 2.47 162 1.80 55r 5 24.51 12. 13.22 53 13.34 98 6.32 54r 6 8.41 10 22.75 33 7.94 56 11.30 4r 30 14.25 63 14.98 159 0.44 161 1.79 58r 2 9.52 7 9.34 43 27.93 41 24.81 12r 19 7.36 32 2.62 137 9.07 143 2.90 15r 13 6.01 19 13.85 66 19.96 136 13.64 20r 16 2.13 15 21.50 92 54.62 129 32.28 65r 2 35.78 2 9.52 5 14.91 10 27.25 61r 1 0.00 2 18.32 10 28.69 11 3.30 59r 2 7.16 8 26.90 97 28.01 99 11.82 51r 2 5.59 18 14.08 102 14.64 170 2.08 24r 2 3.33 8 25.75 57 9.17 125 4.74 50r 3 19.49 10 12.76 36 7.35 44 13.41 25rb 1 7.14 3 28.96 7 17.07 16 9.95 48rb 5 2.96 28 12.17 131 3.49 119 5.58 55rb 4 23.85 14 24.87 49 16.16 100 35.55 Note: ar in mixture number = mixtures that were replicated for statistical purposes; Type I in mixture number = mixes batched using ASTM Type I Portland cement bmixtures batched for a third time due to malfunctions during batching or testing

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84 For all the compressive strength sample s tested, a load-deflection curve was created. These curves prove to be useful in helping to determine whether a compressive strength test went well or not. Viewing each curve, one of the observations made was the transitional behavior of flowable fill in comparison to soil and concrete. This behavior is also noted in a study by Folliard et al. In his study, Folliard discussed how flowable fill demonstrated drastic changes in the deflec tion curve as the curing time increased. At early ages, flowable fill acted more like a soil, with it behaving ductile. As time progressed, the flowable fill behaved more like concrete, with higher strength and low ductility. This behavior is illustrated in Figure 4-1 for batch mix #4. This behavior was typical of most flowable fill mixtures. 0 500 1000 1500 2000 2500 00.020.040.060.080.10.120.140.16 DispIacement (in.)Loads (lbs) 3-day 28-day 56-day Figure 4-1. Load deformation responses for batch mix #4, at 3-, 28and 56-day duration 4.2.3 Volume Change Statistical analysis was used to try to assess which of the three methods provided reliable data. Using data from the three samples attained per batch mixtures, coefficient

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85 of variation was calculated. The coefficient of variation provides a relative measure of data dispersion compared to the mean. When the coefficient of vari ation is small, the data scatter is small compared to the mean. When the coefficient of variation is large compared to the mean, the amount of variation is large. For example, the variation of results from methods 1 and 3 ranged from 80% to 95%, whereas, the coefficient of variation for some specimens using method 2 measured as high as 47.12%. Thus, after comparing the data from all three methods, th e one that produced the most consistent results and lower variations was method 2. The results for volume change along with mixture proportions are shown in Tables 4-5 and 4-6. A total of three readings were taken from each specimen. Those readings were for 1-day, 4-day and 7-day curing intervals. Data from the 4-day and 7-day readings did not show significant difference when compared to the 1-day reading. This information demonstrates that much of the reduction in volume that occurs in flowable f ill transpires at its early curing stage or on the first day. 4.2.4 Proctor Penetrometer Setting Strength (psi) The proctor penetrometer was used for determining the rate of hardening for flowable fill mixtures. Tables 4-7 and 4-8 s how the test results obtained for the mixtures tested using the proctor penetrometer. The ta bles show stress values of all mix samples for three curing durations. The curing durati ons are 6 hours, 1 day and 3 days. Appendix B provides tables containing full detail penetrom eter readings for all curing durations. For those samples designated for testi ng at 6 hours, the following observations were noted. At the beginning, since sample s were soft, it was not possible to get any penetrometer readings. However, at a later time, the samples became stiff and penetrometer readings were obtained. This is due to the fact that flowable fill mixtures

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86 Table 4-5. Volume change results for Experiment #1 Batch Mix Number Cement Content (lb/yd3 ) w/c Ratio Mineral Admixtures (%) Target Air Content Volume Change (%) Coeff. of Var. (%) 4 200 2.0 0 7.5% 2.5% 0.14 0.00 25 50 9.0 0 7.5% 2.5% 0.14 33.72 15 150 4.5 0 7.5% 2.5% 0.60 0.00 23 150 4.5 50 7.5% 2.5% 0.19 42.93 50 100 4.5 0 17.5% 2.5% 2.86 0.08 16 200 4.5 0 7.5% 2.5% 2.10 0.00 61 50 9.0 0 17.5% 2.5% 2.89 8.59 34 100 9.0 50 7.5% 2.5% 0.26 5.82 24 200 4.5 50 7.5% 2.5% 0.31 37.84 59 150 4.5 50 17.5% 2.5% 0.79 4.59 58 100 4.5 50 17.5% 2.5% 1.41 9.04 51 150 4.5 0 17.5% 2.5% 0.98 3.39 69 50 9.0 50 17.5% 2.5% 1.82 26.00 26 100 9.0 0 7.5% 2.5% 1.66 2.51 40 200 2.0 0 17.5% 2.5% 2.12 10.86 16 a 200 4.5 0 7.5% 2.5% 2.10 0.00 14 100 4.5 0 7.5% 2.5% 0.35 27.29 8 200 2.0 20 7.5% 2.5% 3.11 0.00 30 100 9.0 20 7.5% 2.5% 0.16 17.86 18 100 4.5 20 7.5% 2.5% 0.57 5.30 20 200 4.5 20 7.5% 2.5% 1.38 21.80 44 200 2.0 20 17.5% 2.5% 1.33 16.46 65 50 9.0 20 17.5% 2.5% 1.39 44.00 54 100 4.5 20 17.5% 2.5% 0.52 42.14 55 150 4.5 20 17.5% 2.5% 1.06 1.21 12 200 2.0 50 7.5% 2.5% 0.29 36.65 22 100 4.5 50 7.5% 2.5% 0.54 16.79 33 50 9.0 50 7.5% 2.5% 0.46 15.56 19 150 4.5 20 7.5% 2.5% 0.38 11.10 48 200 2.0 50 17.5% 2.5% 0.54 11.07 4a 200 2.0 0 7.5% 2.5% 0.14 0.00 69a 50 9.0 50 17.5% 2.5% 1.82 26.00 Note: amixtures batched for a third time due to malfunctions during batching or testing

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87 Table 4-6. Volume change results for Experiment #2 Batch Mix Numbera Cement Content (lb/yd3 ) w/c Ratio Mineral Admixtures (%) Target Air Content Volume Change (%) Coeff. of Var. (%) 8r 200 2.0 20 7.5% 2.5% 3.11 1.61 16r 200 4.5 0 7.5% 2.5% 2.10 1.98 30r 100 9.0 20 7.5% 2.5% 0.16 17.86 18r 100 4.5 20 7.5% 2.5% 0.57 5.30 14r 100 4.5 0 7.5% 2.5% 0.35 27.29 22r 100 4.5 50 7.5% 2.5% 0.54 16.79 33r 50 9.0 50 7.5% 2.5% 0.46 15.56 23r 150 4.5 50 7.5% 2.5% 0.19 42.93 15-Type I 150 4.5 0 7.5% 2.5% 0.31 22.26 54-Type I 100 4.5 20 17.5% 2.5% 0.25 47.12 25-Type I 50 9.0 0 7.5% 2.5% 0.89 20.12 48-Type I 200 2.0 50 17.5% 2.5% 1.26 24.07 25r 50 9.0 0 7.5% 2.5% 0.41 33.72 34r 100 9.0 50 7.5% 2.5% 0.26 5.82 69r 50 9.0 50 17.5% 2.5% 1.82 26.00 26r 100 9.0 0 7.5% 2.5% 1.66 2.51 40r 200 2.0 0 17.5% 2.5% 2.12 10.86 19r 150 4.5 20 7.5% 2.5% 0.38 11.10 44r 200 2.0 20 17.5% 2.5% 1.33 16.46 48r 200 2.0 50 17.5% 2.5% 0.54 11.07 55r 150 4.5 20 17.5% 2.5% 1.06 1.21 54r 100 4.5 20 17.5% 2.5% 0.52 42.14 4r 200 2.0 0 7.5% 2.5% 0.14 7.55 58r 100 4.5 50 17.5% 2.5% 1.41 9.04 12r 200 2.0 50 7.5% 2.5% 0.29 36.65 15r 150 4.5 0 7.5% 2.5% 0.60 45.73 20r 200 4.5 20 7.5% 2.5% 1.38 21.80 65r 50 9.0 20 17.5% 2.5% 1.39 44.00 61r 50 9.0 0 17.5% 2.5% 3.89 8.59 59r 150 4.5 50 17.5% 2.5% 0.79 4.59 51r 150 4.5 0 17.5% 2.5% 0.98 3.39 24r 200 4.5 50 7.5% 2.5% 0.31 37.84 50r 100 4.5 0 17.5% 2.5% 2.86 9.08 25rb 50 9.0 0 7.5% 2.5% 0.17 23.87 48rb 200 2.0 50 17.5% 2.5% 0.40 19.88 55rb 150 4.5 20 17.5% 2.5% 0.44 4.81 Note: ar in mixture number = mixtures that were replicated for statistical purposes; Type I in mixture number = mixes batched using ASTM Type I Portland cement bmixtures batched for a third time due to malfunctions during batching or testing

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88 Table 4-7. Mix proportions and proctor penetrometer results for Experiment #1 Batch Mix Number Cement Content (lb/yd3 ) w/c Ratio Mineral Admixtures Target Air Content 6-hour Strength (psi) 1-day Strength (psi) 3-day Strength (psi) 4 200 2.0 0 7.5% 2.5% 0 59 277 25 50 9.0 0 7.5% 2.5% 35 83 140 15 150 4.5 0 7.5% 2.5% 34 533 1133 23 150 4.5 50 7.5% 2.5% 50 135 1133 50 100 4.5 0 17.5% 2.5% 0 95 233 16 200 4.5 0 7.5% 2.5% 18 567 1933 61 50 9.0 0 17.5% 2.5% 0 0 64 34 100 9.0 50 7.5% 2.5% 21 77 350 24 200 4.5 50 7.5% 2.5% 28 170 967 59 150 4.5 50 17.5% 2.5% 25 240 1533 58 100 4.5 50 17.5% 2.5% 3 64 110 51 150 4.5 0 17.5% 2.5% 15 227 1167 69 50 9.0 50 17.5% 2.5% 0 10 25 26 100 9.0 0 7.5% 2.5% 13 50 200 40 200 2.0 0 17.5% 2.5% 6 147 1200 16 a 200 4.5 0 7.5% 2.5% 40 200 1067 14 100 4.5 0 7.5% 2.5% 18 117 253 8 200 2.0 20 7.5% 2.5% 0 340 1600 30 100 9.0 20 7.5% 2.5% 23 70 267 18 100 4.5 20 7.5% 2.5% 23 83 225 20 200 4.5 20 7.5% 2.5% 25 50 1107 44 200 2.0 20 17.5% 2.5% 24 350 767 65 50 9.0 20 17.5% 2.5% 2 32 40 54 100 4.5 20 17.5% 2.5% 2 110 330 55 150 4.5 20 17.5% 2.5% 22 333 1300 12 200 2.0 50 7.5% 2.5% 40 280 1317 22 100 4.5 50 7.5% 2.5% 13 75 220 33 50 9.0 50 7.5% 2.5% 35 47 67 19 150 4.5 20 7.5% 2.5% 17 413 1200 48 200 2.0 50 17.5% 2.5% 0 167 1900 4a 200 2.0 0 7.5% 2.5% 22 600 1667 69a 50 9.0 50 17.5% 2.5% 8 27 113 Note: amixtures batched for a third time due to malfunctions during batching or testing

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89 Table 4-8. Mix proportions and proctor penetrometer results for Experiment #2 Batch Mix Numbera Cement Content (lb/yd3 ) w/c Ratio Mineral Admixtures Target Air Content 6-hour Strength (psi) 1-day Strength (psi) 3-day Strength (psi) 8r 200 2.0 20 7.5% 2.5% 0 167 510 16r 200 4.5 0 7.5% 2.5% 40 583 2133 30r 100 9.0 20 7.5% 2.5% 20 77 123 18r 100 4.5 20 7.5% 2.5% 5 53 127 14r 100 4.5 0 7.5% 2.5% 17 57 160 22r 100 4.5 50 7.5% 2.5% 16 77 140 33r 50 9.0 50 7.5% 2.5% 17 38 68 23r 150 4.5 50 7.5% 2.5% 23 113 900 15-Type I 150 4.5 0 7.5% 2.5% 51 427 1567 54-Type I 100 4.5 20 17.5% 2.5% 17 153 517 25-Type I 50 9.0 0 7.5% 2.5% 16 53 90 48-Type I 200 2.0 50 17.5% 2.5% 9 287 1867 25r 50 9.0 0 7.5% 2.5% 14 49 102 34r 100 9.0 50 7.5% 2.5% 21 127 300 69r 50 9.0 50 17.5% 2.5% 0 30 64 26r 100 9.0 0 7.5% 2.5% 31 213 390 40r 200 2.0 0 17.5% 2.5% 0 633 2467 19r 150 4.5 20 7.5% 2.5% 30 500 1247 44r 200 2.0 20 17.5% 2.5% 8 455 2000 48r 200 2.0 50 17.5% 2.5% 13 420 2600 55r 150 4.5 20 17.5% 2.5% 22 202 550 54r 100 4.5 20 17.5% 2.5% 12 153 457 4r 200 2.0 0 7.5% 2.5% 27 617 2600 58r 100 4.5 50 17.5% 2.5% 0 61 177 12r 200 2.0 50 7.5% 2.5% 37 317 2067 15r 150 4.5 0 7.5% 2.5% 23 327 967 20r 200 4.5 20 7.5% 2.5% 24 400 1350 65r 50 9.0 20 17.5% 2.5% 0 35 53 61r 50 9.0 0 17.5% 2.5% 0 33 54 59r 150 4.5 50 17.5% 2.5% 0 60 287 51r 150 4.5 0 17.5% 2.5% 19 180 700 24r 200 4.5 50 7.5% 2.5% 28 120 517 50r 100 4.5 0 17.5% 2.5% 0 95 233 25rb 50 9.0 0 7.5% 2.5% 14 49 102 48rb 200 2.0 50 17.5% 2.5% 23 324 1250 55rb 150 4.5 20 17.5% 2.5% 10 257 425 Note: ar in mixture number = mixtures that were replicated for statistical purposes; Type I in mixture number = mixes batched using ASTM Type I Portland cement bmixtures batched for a third time due to malfunctions during batching or testing

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90 are often plastic several hours after mixing. Such observations were noted only for samples tested after 6 hours of curing. According to a study by Bhat and Lovell [ 45], the terminology walkability is used as a criterion for evaluating and compar ing hardening characte ristics of different flowable fill mixes. The time required for a particular mix to achieve this strength in their study is defined as walkable time for the mix. The penetration resistance corresponding to walkability was defined so that walkable time for any mix can be determined from penetration resistance cu rves. In the Bhat and Lovell study, the walkability tests on various flowable fill mixes indicate that the penetration resistance at that stage varied from 60 to 65 psi depending on the weight of a person. On the basis of their study results, the walkability time is defined as the time required to achieve a penetration resistance of 65 psi. This setti ng time for flowable fill mixture may be used as a reference for penetration resistance and to determine if the mixture has set. Using the proctor penetrometer, the penetration resi stance was obtained for all samples. From the results, it can be seen that penetration resistance for all mixtures, at six hours, is well below the 60 to 65 psi range. The proctor penetrometer is a great tool to help in ascertaining the field conformance of specifications on flowable fill. The proctor penetrometer is used to measure penetration resistance of flowab le fill. However, it is also a useful tool for strength measurement up to a certain point in curing time. This was observed while performing penetrometer resistance tests on 28and 56day samples. As hydration proceeded and flowable fill gained stiffness, the penetrom eter exhibited higher values. When samples became stiff, it became very difficult to penetr ate the penetrometer needle into samples at

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91 required depth. Between 28 and 56 days, sti ffness increased in all samples, and as a result, the test presented inaccurate results du e to the inability of the penetrometer to penetrate through such strengthened flowable fi ll. Hence, the penetr ometer is a good test to use in the field where the strength needs to be measured in early setting times to determine if the flowable fill can support foot tr affic and allow further loading. This would include placement of paving courses for an ear ly opening of traffic, particularly on major arterials or where heavy volumes of traffic require use of the road way during rush hour. 4.2.5 Strength Gained Between 28 and 56 Days To better understand the streng th gain between the various intervals of testing, the percent increase was computed. Figures 4-2 an d 4-3 illustrate the percent increase in strength between 28and 56-day LBR and co mpressive strength results. In these illustrations the w/c ratio is plotted with th e percent increased. The hydration of cement might continue for a long time beyond 28 days. A part of the fly ash and cementitious materials may be participating in the pozzola nic reaction depending on the nature of the 0.00 5.00 10.00 15.00 20.00 25.00 30.00 2.04.59.0 w/c ratio P ercen t I ncrease d % 7.5% air 17.5% air Figure 4-2. Percent increase in 56-day stre ngth as compared to 28-day strength (LBR)

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92 -10.00 0.00 10.00 20.00 30.00 40.00 2.04.59.0 w/c ratio P ercen t I ncrease d % 7.5% air 17.5% air Figure 4-3. Percent increase in 56-day stre ngth as compared to 28-day strength (psi) fly ash [28]. The 56-day strength was as high as 25% or more than the 28-day strength. On average, there was an increase in 56-day strength with respect to 28-day strength. As illustrated in Figures 4-2 and 4-3, th e mixes with high w/c ratio and low design air content have a higher percent increase in bearing strength. This behavior can certainly be explained based on the depleti on of water from the mix while curing. 4.2.6 LBR Oven Sample Results The results of the oven-dried LBR samples give us an exemplary observation of the role that temperature plays in the curing of fl owable fill. As noted earlier, LBR samples were placed into an oven for 2 days of cu ring. The oven was set at a temperature of 110 F for the duration of the curing. The aver age values for the three samples per mix condition are presented in Tables 4-9 and 4-10. Appendix B contains the individual LBR values. A few of the 2-day oven LBR samples test ed did not show higher LBR values. This is because of the hardness of the sp ecimens that caused the LBR machine to

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93 Table 4-9. Two-day oven LBR st rength results for Experiment #1 Batch Mix Number Cement Content (lb/yd3 ) w/c Ratio Mineral Admixtures (%) Target Air Content 2-day Oven Strength (LBR) Coeff. of Var. (%) 4 200 2.0 0 7.5% 2.5% 33 9.84 25 50 9.0 0 7.5% 2.5% 37 20.46 15 150 4.5 0 7.5% 2.5% 66 12.03 23 150 4.5 50 7.5% 2.5% 74 17.72 50 100 4.5 0 17.5% 2.5% 20 5.87 16 200 4.5 0 7.5% 2.5% 110 7.22 61 50 9.0 0 17.5% 2.5% 7 17.32 34 100 9.0 50 7.5% 2.5% 29 14.98 24 200 4.5 50 7.5% 2.5% 103 11.93 59 150 4.5 50 17.5% 2.5% 82 15.79 58 100 4.5 50 17.5% 2.5% 42 11.91 51 150 4.5 0 17.5% 2.5% 89 9.60 69 50 9.0 50 17.5% 2.5% 1 0.00 26 100 9.0 0 7.5% 2.5% 48 34.39 40 200 2.0 0 17.5% 2.5% 51 21.39 16 a 200 4.5 0 7.5% 2.5% 108 27.82 14 100 4.5 0 7.5% 2.5% 61 19.55 8 200 2.0 20 7.5% 2.5% 85 45.44 30 100 9.0 20 7.5% 2.5% 60 21.67 18 100 4.5 20 7.5% 2.5% 37 30.46 20 200 4.5 20 7.5% 2.5% 87 18.39 44 200 2.0 20 17.5% 2.5% 81 13.02 65 50 9.0 20 17.5% 2.5% 9 11.11 54 100 4.5 20 17.5% 2.5% 33 13.80 55 150 4.5 20 17.5% 2.5% 62 23.38 12 200 2.0 50 7.5% 2.5% 145 8.97 22 100 4.5 50 7.5% 2.5% 37 9.75 33 50 9.0 50 7.5% 2.5% 12 8.33 19 150 4.5 20 7.5% 2.5% 62 15.55 48 200 2.0 50 17.5% 2.5% 102 10.33 4a 200 2.0 0 7.5% 2.5% 101 8.90 69a 50 9.0 50 17.5% 2.5% 21 59.67 Note: amixtures batched for a third time due to malfunctions during batching or testing

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94 Table 4-10. Two-day oven LBR st rength results for Experiment #2 Batch Mix Numbera Cement Content (lb/yd3 ) w/c Ratio Mineral Admixtures (%) Target Air Content 2-day Oven Strength (LBR) Coeff. of Var. (%) 8r 200 2.0 20 7.5% 2.5% 35 7.26 16r 200 4.5 0 7.5% 2.5% 126 16.34 30r 100 9.0 20 7.5% 2.5% 37 12.89 18r 100 4.5 20 7.5% 2.5% 23 15.49 14r 100 4.5 0 7.5% 2.5% 32 3.13 22r 100 4.5 50 7.5% 2.5% 46 11.89 33r 50 9.0 50 7.5% 2.5% 23 6.74 23r 150 4.5 50 7.5% 2.5% 186 21.70 15-Type I 150 4.5 0 7.5% 2.5% 145 13.08 54-Type I 100 4.5 20 17.5% 2.5% 45 8.48 25-Type I 50 9.0 0 7.5% 2.5% 20 10.00 48-Type I 200 2.0 50 17.5% 2.5% 144 15.58 25r 50 9.0 0 7.5% 2.5% 15 6.67 34r 100 9.0 50 7.5% 2.5% 79 19.70 69r 50 9.0 50 17.5% 2.5% 10 10.00 26r 100 9.0 0 7.5% 2.5% 56 11.55 40r 200 2.0 0 17.5% 2.5% 60 3.33 19r 150 4.5 20 7.5% 2.5% 106 40.71 44r 200 2.0 20 17.5% 2.5% 133 1.99 48r 200 2.0 50 17.5% 2.5% 242 3.16 55r 150 4.5 20 17.5% 2.5% 93 18.72 54r 100 4.5 20 17.5% 2.5% 57 17.28 4r 200 2.0 0 7.5% 2.5% 174 10.64 58r 100 4.5 50 17.5% 2.5% 67 9.55 12r 200 2.0 50 7.5% 2.5% 197 5.14 15r 150 4.5 0 7.5% 2.5% 107 23.80 20r 200 4.5 20 7.5% 2.5% 108 11.60 65r 50 9.0 20 17.5% 2.5% 11 23.59 61r 50 9.0 0 17.5% 2.5% 4 13.32 59r 150 4.5 50 17.5% 2.5% 136 20.23 51r 150 4.5 0 17.5% 2.5% 94 21.42 24r 200 4.5 50 7.5% 2.5% 60 26.59 50r 100 4.5 0 17.5% 2.5% 45 7.09 25rb 50 9.0 0 7.5% 2.5% 12 25.00 48rb 200 2.0 50 17.5% 2.5% 232 3.95 55rb 150 4.5 20 17.5% 2.5% 129 15.20 Note: ar in mixture number = mixtures that were replicated for statistical purposes; Type I in mixture number = mixes batched using ASTM Type I Portland cement bmixtures batched for a third time due to malfunctions during batching or testing

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95 terminate itself. Some of the specimen LBR plots show the LBR values going up and then coming down and then going up again. This peculiar behavior was observed for many of the samples containing fly ash, sl ag and high cement content. Many of the samples demonstrating the aforementioned behavior showed signs of fracture and cracking when the LBR test was performed. Table 4-11 provides comparison of mixt ure components and their influence on accelerated 2-day oven and 28-da y LBR strength. The table shows mixtures with a low w/c ratio exhibit a high accelerated strength. This demonstrates the heat of hydration occurring fully due to the oven temperature, which acts as a catalyst to speed up curing. Table 4-11. Comparison of mixture component s and their influence on accelerated 2-day oven and 28-day LBR strength Design Air Content (%) W/C Ratio 2-day Oven Strength (LBR) 28-day Oven Strength (LBR) 2.0 99 142 4.5 81 133 7.5 9.0 40 65 2.0 95 147 4.5 67 115 17.5 9.0 10 16 Design Air Content (%) Mineral Admixtures (%) 2-day Oven Strength (LBR) 28-day Oven Strength (LBR) 0% 68 123 20% fly ash 64 92 7.5 50% slag 83 124 0% 46 99 20% fly ash 58 85 17.5 50% slag 75 111 Design Air Content (%) Cement Content (lbs/yd3 ) 2-day Oven Strength (LBR) 28-day Oven Strength (LBR) 50 17 16 100 45 75 150 107 136 7.5 200 98 171 50 10 16 100 42 51 150 93 178 17.5 200 95 147

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96 4.3 Factors Affecting Strength 4.3.1 Water-to-Cement (w/c) Ratio Strength, because it can easily be determin ed, is the most universally used measure for flowable fill quality. Like concrete, the compressive strength is inversely related to the water/cement (w/c) ratio. To identify this relationship, plots of w/c ratio versus strength were created. The relationship betw een strength and w/c ra tio for two levels of air content are shown in Fi gures 4-4 through 4-7. It is common knowledge among 0.00 50.00 100.00 150.00 200.00 250.00 300.00 0.02.04.06.08.010.0 w/c ratio Strength, LBR design air content 7.5% Figure 4-4. Relationship betw een 28-day bearing strength (LBR) and w/c ratio at 7.5% design air content 0.00 50.00 100.00 150.00 200.00 250.00 300.00 0.02.04.06.08.010.0 w/c ratio Strength, LBR design air content 17.5% Figure 4-5. Relationship betw een 28-day bearing strength (LBR) and w/c ratio at 17.5% design air content

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97 0.00 50.00 100.00 150.00 200.00 0.02.04.06.08.010.0 w/c ratio Strength, psi design air content 7.5% Figure 4-6. Relationship between 28-day co mpressive strength (psi) and w/c ratio at 7.5% design air content 0.00 50.00 100.00 150.00 200.00 0.02.04.06.08.010.0 w/c ratio Strength, psi design air content 17.5% Figure 4-7. Relationship between 28-day co mpressive strength (psi) and w/c ratio at 17.5% design air content engineers that the strength, like other desirabl e properties of flowable fill under given job conditions, is governed by the quantity of mi xing water used per unit of cement. Thus, the ratio of water to cementitious material ha s a major influence on the strength of flowable fill. For the plots in Fi gures 4-4 through 4-7, this rela tionship is evident between the w/c ratio and strength. Since w/c ratio primar ily controls strength, it is expected that strength decreases as the amount of water increases. The plot s illustrate that as the w/c ratio increases, strength decreases. Alt hough a particular w/c ratio is specified in designing a mix, there is often a great deal of uncertainty ove r what the true w/c ratio is when the mix is actually placed.

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98 4.3.2 Cement Content Cement content is an important factor in determining bearing strength. The plots in Figures 4-8 through 4-13 indica te the strength in relation to cement content for airentrained mixtures (7.5% and 17.5 %) by design. Just like w/c ratio, one expects strength to increase with increasing cement content. This normally occurs for mixtures containing normal workability. This is apparent with pl ots showing the relations of strength with cement content. The plots indicate that mixes with higher cement content exhibit higher strength for both LBR and compressive strength samples. 0.00 50.00 100.00 150.00 200.00 250.00 300.00 0.050.0100.0150.0200.0250.0 cement content, lb/yd3Strength, LBR design air content 7.5% Figure 4-8. Relationship between 28-day be aring strength (LBR) and cement content at 7.5% design air content 0.00 50.00 100.00 150.00 200.00 250.00 300.00 0.050.0100.0150.0200.0250.0 cement content, lb/yd3Strength, LBR design air content 17.5% Figure 4-9. Relationship between 28-day be aring strength (LBR) and cement content at 17.5% design air content

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99 Figure 4-10. Relationship between 28-day compressive strength (psi) and cement content at 7.5% design air content 0.00 50.00 100.00 150.00 200.00 0.050.0100.0150.0200.0250.0 cement content, lb/yd3Strength, psi design air content 17.5% Figure 4-11. Relationship between 28-day compressive strength (psi) and cement content at 17.5% design air content Figure 4-12. Relationship between 28-d ay LBR strength and cement content 0.00 50.00 100.00 150.00 200.00 0.050.0100.0150.0200.0250.0 cement content, lb/yd3Strength, psi design air content 7.5% 0.00 50.00 100.00 150.00 200.00 250.00 050100150200250 cement content, lb/yd3Strength, LBR 7.5% air 17.5% air design air content 7.5% design air content 17.5%

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100 Figure 4-13. Relationship between 28-day compressive strength (psi) and cement content 4.3.3 Effect of Air Content on Strength In concrete, air entrainment increases workability and permits a reduction in water content to maintain a constant slump. Even though air content does not have a significant effect on the strength of the flowable fill, it is importan t in determining an acceptable range of air content. To investigate the eff ect of variation of ai r content on strength, flowable fill mixtures were designed using lo w and high air content. Strength results for LBR and compressive strength samples illustra te that high air mixtures exhibit higher strength than low air mixtures for flowable fill. An investigation of the e ffect of air entrainment in conventional concrete by William Lerch [46] supports these results. Co mparison of mixtures with varying cement contents indicated that flowable fill had a large percent reduction in strength with a low air-content mixture and a small percent reduction for the high air-content mixture. In general, the reduction in strength could be ne glected except when the air content is below the 7.5% design air content. In this study, it was observed that the proper air content in a well designed mix limited strength, generated adequate flow, e liminated segregation, and greatly reduced bleeding by producing a cohesi ve homogeneous mixture. 0.00 50.00 100.00 150.00 050100150200250 cement content, lb/yd3Strength (psi) 7.5% air 17.5% air design air content 7.5% design air content 17.5%

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101 4.3.4 Effect of Mineral Admi xtures (Fly Ash and Blast Furnace Slag) on Strength Concrete mixes containing mineral admixtures such as fly ash or slag will generally require less water than concrete mixes containing only cement [44]. Like flowable fill, the mixes containing cementitious material show a lower w/c ratio than the concrete mix. Strength of flowable fill can be improve d by adding a reasonable amount of mineral admixtures to a mix. The calcium oxide (CaO ) content in fly ash is believed to be the most important variable aff ecting strength. It acts to improve workability and is a cementing agent that improves long-term strength. The silica glass in fly ash and slag reacts with the free lime liberated during hydr ation of Portland cement to form a more stable cementing compound. The mixes containing mineral admixtures exhibited higher strength, less bleeding, and segregation. This is evident in Figures 4-14 and 4-15. The mixes also exhibited less bleeding and segregation which was established through visual observation in this study. Thorough observation during mixing revealed that mixes containing a high percentage of fine aggregates demonstrated bleeding at an early phase of mixing and that as the mixing 0.00 40.00 80.00 120.00 160.00 0%20% fly ash50% slag Mineral Admixtures, %28-day strength, LBR 7.5% air 17.5% air Figure 4-14. Effect of mineral admixtures on 28-day LBR strength

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102 0.00 50.00 100.00 150.00 200.00 0%20% fly ash50% slag Mineral Admixtures, %56-day strength, LBR 7.5% air 17.5% air Figure 4-15. Effect of mineral admixtures on 56-day LBR strength was prolonged, the bleeding slowed. This phenomenon exhibited in mixes containing zero mineral admixtures. Excessi ve bleeding often indicates a ba d mix. This type of mix should be avoided in the field due to the possibility of the mix not having good flow. In addition, such a mix may result in excessi ve initial subsidence of the surface after placement. 4.4 Comparison of Mix Using Type I/II Cement vs. Type I Cement During the research experiment, it was disc overed that certain mixtures utilized Type I cement as opposed to Type I/II cement obtained for the research project. When this was discovered, additional mixture was pr epared using strictly Type I cement. The compressive and LBR strength results were th en compared to similar mixtures where Type I/II cement was used. Figures 4-16 through 4-23 shown below are plots of the comparison of both LBR and psi compressive strengths for four mixes. The four mixtures chosen included both high and low cement content. Based on the results obtained for those mixtures, it wa s concluded that the di fference in strength between the two types of cement was not significant.

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103 0.00 20.00 40.00 60.00 80.00 100.00 120.00 132856 Time (days)Strength (psi) Type I/II BM15 Type I BM15 Figure 4-16. Compressive strength (psi) of Type I/II vs. Type I cement for BM15 0.00 50.00 100.00 150.00 200.00 250.00 0.25132856 Time (days)Strength (LBR) Type I/II BM15 Type I BM15 Figure 4-17. LBR strength of Type I/II vs. Type I cement for BM15 0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 132856 Time (days)Strength (psi) Type I/II BM25 Type I BM25 Figure 4-18. Compressive strength (psi) of Type I/II vs. Type I cement for BM 25

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104 0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 0.25132856 Time (days)Strength (LBR) Type I/II BM25 Type I BM25 Figure 4-19. LBR strength of Type I/II vs. Type I cement for BM 25 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 132856 Time (days)Strength (psi) Type I/II BM48 Type I BM48 Figure 4-20. Compressive strength (psi) of Type I/II vs. Type I cement for BM 48 0.00 40.00 80.00 120.00 160.00 200.00 0.25132856 Time (days)Strength (LBR) Type I/II BM48 Type I BM48 Figure 4-21. LBR strength of Type I/II vs. Type I cement for BM 48

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105 0.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00 132856 Time (days)Strength (psi) Type I/II BM54 Type I BM54 Figure 4-22. Compressive strength (psi) of Type I/II vs. Type I cement for BM 54 0.00 20.00 40.00 60.00 80.00 100.00 120.00 0.25132856 Time (days)Strength (LBR) Type I/II BM54 Type I BM54 Figure 4-23. LBR strength of Type I/II vs. Type I cement for BM 54 4.5 Drying Shrinkage (Volume Change) Based on the results obtained, it was determ ined that the word shrinkage was not appropriate terminology to descri be the occurrence of settlement in flowable fill. Instead, the term volume change was adopted to desc ribe drying shrinkage in flowable fill. The occurrence of volume change in flow able fill under service conditions arises from a number of different stimuli. Some of these stimuli are applied stress, change in moisture content, and changes in temperatur e. The plots below illustrate the effected volume change in flowable fill due to w/c ra tio, cement content, and mineral admixtures.

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106 Table 4-12 shows a comparison of mixt ure components and their influence on percent volume change. In Figure 4-24, the effect of the w/c ratio on the change in volume in flowable fill indicates that volume change increases with increased w/c ratio for mixtures with high air-content, while th e change in volume for mixes with low aircontent is minimal and does not appear to be significant. Table 4-12. Comparison of mixture compone nts and their influence on percent volume change Design Air Content (%) W/C Ratio Volume Change (%) 2.0 1.18 4.5 0.71 7.5 9.0 0.59 2.0 1.33 4.5 1.27 17.5 9.0 2.37 Design Air Content (%) Mineral Admixtures Volume Change (%) 0% 0.88 20% fly ash 1.12 7.5 50% slag 0.34 0% 2.47 20% fly ash 1.07 17.5 50% slag 1.14 Design Air Content (%) Cement Content (lbs/yd3 ) Volume Change (%) 50 0.43 100 0.59 150 0.39 7.5 200 1.22 50 2.37 100 1.60 150 0.94 17.5 200 1.33 The effect of cement content on flowable fill volume change seems to have an effect opposite of that of the w/c ratio as illustrated in Figure 4-25.

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107 0.00 0.50 1.00 1.50 2.00 2.50 0.02.04.06.08.010.0 w/c ratioVolume Change, % 7.5% air 17.5% air Figure 4-24. Effect of w/c ratio on volume change 0.00 0.50 1.00 1.50 2.00 2.50 050100150200250 cement content, lb/yd3Volume Change, % 7.5% air 17.5% air Figure 4-25. Effect of cement content on volume change Figure 4-26 represents the effect of mineral admixtures on flowable fill volume change. According to Kosmatka and Panarese when used in low to moderate amounts, the effect of fly ash and blast furnace sl ag on the drying shrinkage of concrete is generally small and of little practical significance. Like concrete, the drying shrinkage or volume change for flowable fill mi xtures in this study was minimal.

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108 0.00 0.50 1.00 1.50 2.00 2.50 3.00 0%20% fly ash50% slag Mineral Admixtures, %Volume Change, % 7.5% air 17.5% air Figure 4-26. Effect of minera l admixtures on volume change 4.6 Interpretation of Plastic Test Results Tests for plastic properties were performed at the end of every batch mix. The characteristics measured were unit weight, air co ntent, flow consistency, and temperature. Tables 3-3 and 3-4 in Chapter 3 give the out come of the plastic tests performed. The unit weights for flowable fill mixtur es in this study ranged from 99.92 to 137.28 lb/ft3. In comparison to normal concrete mixtures, the unit weight for airentrained flowable fill mixtures was slightly less than those of normal concrete mixtures. Air content was measured us ing the pressure method. This method was found to be simple and reliable. The measuring instrume nt used was a calibrated pressure meter. The mixtures used in this study were designe d using a low air-conten t target (7.5.5%) and a high air-content target (17.5 2.5%). At the time of batching, care was taken to ensure that the target air content was achieve d. It was extremely difficult to obtain the entrained air target for mixtures with very low sand-to-water ratio or certain stiff mixtures. For example, during the batchi ng of batch mix #16 there was a problem in obtaining the target air conten t (7.5% 2.5%). After several attempts were made to

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109 reach the target air content, the only attainable air conten t was established at 1.3%. Below is the amount of air entraining admixture (AEA) added on each of the attempts and the resulting air content: Attempt 1: AEA 100 ml, 0.5% air Attempt 2: AEA 100 ml, 1.0% air; and Attempt 3: AEA 1400 ml, 1.3% air. After adding the AEA to the mix, the mixer was rotated for seven to ten minutes. It was observed that the mix had foam or air bubbles forming on the surface of mix. This was an indication that the air was difficult to re tain in the mix, due to the fluidity of the mix (sand-to-water ratio = 1. 74). It is believed that mixtures containing high water content prevents the formation of entrained ai r voids, which thus rendered the AEA to be noneffective. For various mixtures, air-entra ining dosage rates were increased to the dosage recommended by the manufacturer, but to no avail, the target air contents were not achieved. The flow consistency was measured in accordance to ASTM D 6103 test procedures. ASTM D 6103 requires the impl ementation of an open-ended flow cylinder that is 150 mm (6 in.) in length and has a 76 mm (3 in.) inside diameter. The flow cylinder used throughout this experiment was made of PVC. Once the flowable fill had been properly mixed, the materi al was placed into one end of the cylinder, while the other rested on a flat wet surface. Both the flow cylinder and flat surface were dampened with water prior to testing. After a few seconds of filling the cylinder, it was quickly and carefully raised in the vertical direction. The largest resul ting spread diameter was then immediately measured using a ruler by ta king the average of two perpendicular measurements.

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110 For a flowable fill to be self-leveling a nd ready for use in filling void spaces without requiring vibration, the av erage spread diameter should be between 8 and 12 in. [45]. This type of spread is also known to provide suitable flow during placement of flowable fill in the field. Flow values in Tables 3-3 and 3-4 ranged from 0.00 to 10.50 in. Figure 4-27 is a bar chart plotting the sand-to -water ratio versus the flow diameter. To understand the behavior of one class of mi xtures having high flow and the other class having less flow, it is critical to understand the behavior of di fferent material ingredients in the flowable fill. Water, for example, is expected to be the key ingredient responsible for flow. Looking at the wate r/cement (w/c) ratio per mixtur es, however, it shows that most of the mixes with low-flow spread ar e those that contain a high w/c ratio. The differences in flowability can be attributed to the amounts of mineral admixtures that a mix contains. 0.00 2.00 4.00 6.00 8.00 10.00 12.001. 7 3 1 .74 1. 8 3 2 .59 2 .6 0 3 .25 5 .3 0 5 .31 5 .4 0 6 .06 6 .0 9 6 .29 6 .3 8 7 .17 7 .2 0s/w ratioFlow diameter, in. Figure 4-27. Flow diameter vs. sand-to-water ratio

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111 CHAPTER 5 STATISTICAL ANALYSIS 5.1 Introduction One of the objectives of this study was to develop predictive m odels for strength and volume change of flowable fill. This sec tion details the statistical approaches and the statistical derivation of the linear regression equations that resulted in the assessment of the statistical models. 5.2 Statistical Model Derivation Multiple linear regression analysis is the multivariate method used for analyzing the laboratory data obtained in this study. Regression analyses are defined as a set of statistical procedures for assessing the re lationship between one random variable and several fixed independent variable s [40]. In this data analysis, the strength (i.e., LBR and compressive) and shrinkage (volume change) were the dependent variables, while cement content, air content, w/c rati o, and mineral admixtures were the independent variables (also referred to as explanatory variables). A simple mathematical regression equation is generally represented by (,) yfxb (5-1) where y is the dependent variable, b contains the regression parameters, x is a set of independent variables, and is the random error of the estim ated function. The ordinary least squares method was applied for estimati ng the regression parameters. The least squares method minimizes the sum of squares of the differences between the predicted

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112 and the actual values of th e dependent variable. Using the least squares method takes into account the following assumptions: 1. Stability of the regression model. This implies that the value of the dependent variable y is an additive comb ination of the independe nt predictor variables represented as x. Theoretically, if there is an inte raction effect such that the value of one explanatory variable depends on one or more other explanatory variables, the estimates of the regression coeffici ents are statistically unreliable. 2. Constancy of error variance. It is assumed that the error term ( ) is not correlated with the independent variab les and assumes constant va riability over the range of the variables. The dependent variable, y, is also assumed to have a constant variance. This entails that the dependent variables are independent of each other. 3. Normality of the response variable, y. The normality of regression formulation is usually assessed through normality residual plots. 4. Normality of the error terms, The least squares approach for estimating regression parameters is most efficient wh en the residuals or errors also have a normal probability distribution. In summary, the validity of a multiple re gression model uses the classical assumptions described above. Those assumptions are linearity, independency and normality. To satisfy the basic assumptions, it is cu stomary to apply various remedies and diagnostics for individual variab les. Some of these remedi es involve transformation. Transformation or re-expression of the respons e is the primary tool for dealing with violations of assumptions. For example, the logarithm of the response might be analyzed. The idea is that the responses on the tran sformed scale match our assumptions more closely, so that we can use standard methods on the transformed data. In simple terms, transformation of variables is necessary so as to simplify or stra ighten relationships, stabilize variances, and improve normality [41]. For this study, some of the explanatory variables had a nonlinear trend with the valu es of the strength and volume change. For example, cement content had a curvilinear re lationship with the value of the response variables, so a quadratic term relating to the cement cont ent was used to convert the

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113 nonlinear relationship into a linear one. Similarly, the data interpretation showed that the w/c ratio had a nonlinear relationship with th e response variable and the relationship was straightened by a transformation on its variable. When the classical assumptions of constant variance and normality are violated, a nonlinear transformation of the response may improve the regression fit. Evaluation of the data revealed normal distributions of th e residuals, indicating that no transformation was necessary to satisfy this assumption [41]. When the effects of the independent vari ables on the response variable are not additive, the effect of one independent variable depends on the levels of the other predictor variables [40] In this study, the polynomia l regression models required to simplify the relationships between strength (i.e., LBR, compressive) and volume change contained interaction effect s, resulting in non-constant variance. A simple and commonly used means of modeling the interac tion effect of two pr edictor variables on the response variable is by a cross-product term called an interaction term [40]. Consequently, the interaction terms for all explanatory variables were included in the regression equations. After considering the potential regressi on problems and taking their remedies, regression models were generated using ordi nary least squares method. Because the independent variables were reasonably or thogonal, ordinary least squares results remained almost the same regardless of wh ich other variables were included in the model. All possible subset re gressions were computed and ev aluated to provide the best statistical model. This method was feasible because the number of independent variables

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114 was not large; for this case, the variable num ber was 4. Prior to incorporating the data into the regression analysis, they were fully evaluated for errors. Stepping through the model selection process, the statistical model that worked best was developed for various curing durations along with percent volume changes. The resulting regression equation ex pressed in mathematical format is provided below. 222 01234567 8910111213 t y abcdacd abacadbcbdcd (5-2) where a = cement content, lb/yd3 b = air content, % c = w/c ratio d = mineral admixtures (i.e., 0% 20% fly ash, 50% slag); and i = coefficients. Estimated LBR strength model equations: 2 28dayLBR 22 299.0400.92818.78024.8173.2140.000756 1.1870.07920.03370.1450.00426 1.1500.03040.114 y abcda cdabacad bcbdcd (5-3) 2 56dayLBR 22 917.4234.02933.638129.9301.7670.00840 4.9640.06010.09190.3590.00373 2.6020.03750.186 y abcda cdabacad bcbdcd (5-4) Estimated psi strength model equations: 2 28daypsi 22 94.9341.5230.68145.6161.2300.00294 3.3650.02720.009640.06350.0100 0.2320.04180.145 yabcda cdabacad bcbdcd (5-5) 2 56daypsi 22 52.8310.24414.1301.5071.4150.00135 1.2150.02890.05270.01300.000565 1.1440.004190.0103 yabcda cdabacad bcbdcd (5-6)

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115 Estimated percent volume change model equations: %volumechange 222 3.9450.004570.1930.6670.0284 0.00001050.03730.0001850.000116 0.009040.00007000.01280.000165 0.00445 yabcd acdab acadbcbd cd (5-7) The mathematical equations shown above represent the regression model equations for estimating the LBR strength, compressive strength in psi, as well as the volume change. Table 5-1 provides th e standard errors and other pe rtinent information for each regression model equation. The accuracy of the fitted data for each re gression model can be better understood by inspection of Figures 5-1 through 5-3. Th ese figures plot the fitted versus the standardized residuals. For Figures 5-1 and 52, it is clear that both plots show a rightopening megaphone shape. This clearly indi cates that variability of the residuals increased with response mean. The conclusions drawn from these gr aphs were that the fitted values provided a reasonable estimate of the actual values and the regression models could be useful for designing a flowable fill mixture. The residuals plot in Figure 5-3 does not provide a clear megaphone shape as in Figures 5-1 and 5-2, thus it was difficult to determine whether or not the residua ls increased with the response mean. The results of analysis of variance are provide d in Appendix C. Appendix C contains the parameters and standard error for each regr ession equation along with tables and figures displaying the comparison of measured labora tory and predicted results. The results showed highly significant differences betw een some independent variables for all models. The multiple correlation coefficients (R-square) were 0.846 for 28-day LBR and 0.853 for 56-day LBR.

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116 Table 5-1. Standard error of regression co efficients for equations relating mixture constituents to LBR, compressive strength and percent volume change Equation Models Coefficient ( i ) y28day LBR y56day LBR y28day psi y56day psi y% volume change 0 = 549.872 624.940 278.578 341.164 1.403 1 = 3.740 4.250 1.895 2.320 0.00954 2 = 12.536 14.248 6.351 7.778 0.0320 3 = 111.985 127.273 56.734 69.480 0.286 4 = 1.847 2.100 0.936 1.146 0.00472 5 = 0.00630 0.00716 0.00319 0.00391 0.0000161 6 = 5.165 5.870 2.617 3.205 0.0132 7 = 0.00915 0.0104 0.00464 0.00568 0.0000234 8 = 0.0524 0.0595 0.0265 0.0325 0.000134 9 = 0.392 0.445 0.199 0.243 0.00100 10 = 0.00658 0.00748 0.00334 0.00408 0.0000168 11 = 1.325 1.506 0.671 0.822 0.00338 12 = 0.0278 0.0316 0.0141 0.0172 0.0000709 13 = 0.129 0.147 0.0653 0.0800 0.000329 R-Square 0.846 0.853 0.880 0.859 0.569 MSE 986.578 1274.340 253.223 379.783 0.00643 DFE 159.00 159.00 159.00 159.00 159.00 COV 27.718 25.822 25.767 24.210 62.228 Figure 5-1. Residuals versus fitt ed values plot (28-day LBR) Standardized Residual -100 0 100 200 Fitted Value-1000 100200 300

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117 Figure 5-2. Residuals versus fitt ed values plot (28-day psi) Figure 5-3. Residuals versus fitted values plot (% volume change) -0.12 -0.11 -0.10 -0.09 -0.08 -0.07 -0.06 -0.05 -0.04 -0.03 -0.02 -0.01 0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10 0.11 0.12 0.13 0.14 0.15 0.16 0.17 Fitted Value-0.02 0.000.020.040.06 0.080.100.120.140.16 0.18 0.200.220.240.26 0.28 0.300.320.340.36 0.38 0.40 0.420.440.460.48 Standardized Residual -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 Fitted Value-100 10 2030 4050 6070 80 90100110120130 140150 Standardized Residual

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118 An attempt was made to simplify the nu mber of regression equations into one equation for estimating the strength. This re duction required adding time (t) as a variable into the model. This proved to be daun ting and unreliable. Using the laboratory information, the data for all samples and curing duration (1, 3, 28, and 56 days) were combined and input into a st atistical software package (S AS). The analysis results yielded an R2 value of 0.69. Comparing this value to other selected models demonstrated a weak correlation and a lack of fit. 5.3 Accelerating Strength Testing 5.3.1 Background Obtaining 28-day excavatable flowable fill requires restricting the bearing strength to a minimal value to allow for possible future excavation. To ensure that the strength of a particular mix of flowable fill does not ex ceed this value, samples are required to be kept for 28 days for strength testing before this mix is used in the field. This can cause major delays in construction work and ups ets the economics of application of this material. This is viewed by many as a major dr awback in the application of flowable fill, particularly from the contractors perspectiv e. This disadvantage has necessitated the development of accelerated strength testi ng to reduce the strength testing time. Accelerated strength testing sp eeds up the process of hydratio n of the cement in flowable fill. The increase in temperature accelera tes hydration of the cement. The ASTM C 684 standard specifications discu ss techniques to accelerate th e development of strength for concrete. The techniques specified in AS TM are the warm water method, boiling water method, autogenous curing method, and hi gh temperature and pressure method. The warm water method specifies curing th e concrete specimens immediately after casting the samples in water at 95 F for 24 hours. The boiling water method involves

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119 curing the concrete specimens one day after ca sting in boiling water for 3.5 hours. The autogenous method involves storage of specimens in insulated curing containers in which the elevated curing temperature is obtained from the heat of hydration of cement. The high temperature method involves simultaneous application of elevated temperature and pressure to the concrete using special contai ners. However, these techniques cannot be applied directly to flowable fill due to th e quantity of cement being insignificant in relation to the total volume of the mix. 5.3.2 Accelerated Curing The samples considered for this evaluation included LBR samples which were prepared in the same manner as other LBR samples. A drying oven was used to accelerate the curing of flowable fill samples. After each batch mix, oven samples were collected and assembled for placement in the oven. Samples were tested at curing intervals of 2 days. The LBR samples were not de-molded prior to testing. All samples tested showed no sign of deterioration. For mo st of the curing period, the integrity of the samples was not impacted and no damage caused to samples. Samples were strong enough to withstand stress during testing which is an indication that no damage existed internally. 5.3.3 Analysis After the oven-dried LBR samples were tested, the results were statistically analyzed for developing an accelerated strengt h. The accelerated strength was then used to predict the 28-day strengt h using the standard curing 28-day LBR results and the accelerated curing oven-dried results. Proper sample amounts were collected per mix to estimate the potential later-age strength from a measured early-age accelerated st rength as stated in a previous section of

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120 this research. These mixtures included si milar materials to those that are used in construction. Ordinary least squares regres sion analysis was used to obtain the equation of the line representing the relationship betw een standard cured and accelerated strengths [47, 48]. This relationship was applicable on ly to the specific materials and accelerated test procedures that were used. To account for the uncertainty in the resulting regression line, confidence bands for the line were esta blished [47]. Then, for a new accelerated strength, the confidence interval for the aver age later-age strength was estimated. These procedures were based on the earlier wo rk of Willis [49] and Carino [50]. In this study, it was assumed the relati onship between the standard or normal curing strength ( Y ) and the accelerated strength ( X ) could be represente d by a straight line with the following equation: YabX (5-8) However for some flowable fill mixtures, the relationship between these two types of strength may not be linear. For these situ ations, the measured strength values should be transformed by taking their natural logarithms. The natura l logarithms of the strengths were used to obtain the average X and Y values to be used in la ter calculations. The last step was performing exponentiation to convert the computed confidence intervals to strength values. Assuming that n pairs of ( Xi, Yi) values are obtained from laboratory testing, where Xi and Yi are the average strengths of accelerated and standard-cured specimens, the intercept, a and slope, b of the straight line would be determined us ing the procedure of ordinary least squares [47]:

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121 x y x xS b S (5-9) aYbX (5-10) where xyiiSXXYY (5-11) 2xxiSXX (5-12) Thus, Sxy is the sum of x deviations multiplied by y deviations and Sxx is the sum of x deviations squared. i X X n (5-13) iY Y n (5-14) The residual standard deviation, Se, of the best-fit line is given by the following: 21 2 x y eyy x xS SS nS (5-15) where 2 yyiSYY (5-16) To illustrate the procedure, consider the 18 pairs of accelerated and standard-cured 28-day strength samples which were ovendried for two days (see second and third columns of Table 5-2). Each number repr esents the average strength of two LBR specimen samples. The accelerated strength ( Xi) was the value obtained from samples

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122 Table 5-2. Estimation of confid ence interval for 28-day strength Confidence Limit, LBR Mixture # Accelerated Strength, Xi LBR 28-day Strength, Yi LBR Estimated Strength, Y LBR Wi LBR Lower Upper Sxyi Sxxi Syyi 60.00 116.00 92.51 9.57 251.53 820.19 77.14 62.50 118.00 95.33 9.42 85.91 104.75 177.29 683.24 46.01 65.00 126.00 98.15 9.29 88.85 107.44 -28.77 558.80 1.48 32.00 44.00 60.96 11.79 49.17 72.75 4575.45 3207.96 6525.86 35.00 60.00 64.34 11.51 52.83 75.85 3474.88 2877.13 4196.81 8 37.00 69.00 66.59 11.32 55.27 77.92 2880.56 2666.57 3111.72 137.00 173.00 179.28 11.03 168.25 190.31 2331.84 2338.80 2324.90 138.00 192.00 180.40 11.12 169.28 191.52 3317.92 2436.52 4518.15 160.00 199.00 205.19 13.28 191.91 218.48 5296.22 5092.41 5508.20 185.00 214.00 233.37 16.12 217.25 249.48 8597.07 9285.46 7959.71 202.00 240.00 252.52 18.19 234.34 270.71 13061.15 12850.74 13275.01 12 203.00 273.00 253.65 18.31 235.34 271.96 16950.29 13078.46 21968.34 47.33 75.00 78.23 10.45 67.79 88.68 2056.47 1706.42 2478.32 66.38 97.13 99.70 9.22 90.48 108.92 615.52 495.46 764.68 69.29 98.96 102.98 9.09 93.89 112.07 499.64 374.38 666.82 31.00 40.00 59.83 11.89 47.95 71.72 4886.79 3322.24 7188.12 32.00 43.00 60.96 11.79 49.17 72.75 4632.09 3207.96 6688.42 14 33.00 68.00 62.09 11.69 50.39 73.78 3159.33 3095.69 3224.28

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123 oven-dried for two days for excavatable mi xes. Using the preceding equations, the following values were obtained: X = 88.64 LBR Y = 124.78 LBR Sxx = 68098.44 (LBR)2 Syy = 90523.97 (LBR)2 Sxy = 76735.26 (LBR)2 The slope of the line was b = 76735.26 / 68098.44 = 1.13, and the intercept was 124.78 1.13 88.64 = 24.90 LBR. Therefore, the equation of the relationship between accelerated strength ( X ) and standard-cured strength ( Y ) was as follows: 24.9021.1268 YX (LBR) (5-17) Figure 5-4 shows the 18 data pa irs and the calculated best-f it line. The regression graph presented in Figure 5-4 was forced to zero (y -intercept was set to zero). The residual standard deviation of the line, Se, was as follows: 2116,980.69 20,802.0612.00439LBR 18215,589.21eS (5-18) R2 = 0.9552 0.00 50.00 100.00 150.00 200.00 250.00 300.00 0.0050.00100.00150.00200.00250.00 Accelerated curing strength, LBR28-day strength, LBR Figure 5-4. Accelerated curing vs. 28-day normal curing strength

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124 5.3.4 Confidence Band for Regression Line Because of the uncertainties in the estimates of the slope and the intercept of the line, there was uncertainty when the line was used to estimate the average standard-cured strength from a measured accelerated stre ngth. This uncertainty was expressed by constructing the 90% confidence band for the line [47, 51]. This band was obtained by calculating Y for selected values of Xi using the equation of the line and plotting Yi Wi, versus Xi. The term Wi was the half-width of the confidence band at Xi and was given by the following equation: 21 2i ie xx X X WSF nS (5-19) where Se = residual standard deviation fo r the best-fit line (Equation 5-15) F = value from F-distribution table fo r 2 and n-2 degrees of freedom and significance level 0.10 n = number of data points used to establish regression line Xi = selected value of accelerated strength; and X = grand average value of accelerated stre ngth for all data used to establish the regression line. The fourth column in Table 5-2 lists the estimated average 28-day strengths for the accelerated strengths in co lumn 2. The value of Wi at each value Xi is listed in the fifth column of Table 5-2. Finally, columns 6 and 7 list the values of the lower and upper 90% confidence limits. Note the width of the confidence band was narrowest when Xi = X because the second term under the square ro ot sign in Equation 5-19 equaled zero. 5.3.5 Estimate of Later Strength Supposing that the average accelerated stre ngth of two LBR samples made in the lab from similar flowable fill was 35.67 LBR from the regression equation, the estimated average 28-day, standard-cured strength was 65.075 LBR. If the accelerated strength was

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125 known without error, the 90% c onfidence interval for the aver age 28-day strength would be 29.44 to 70.99 LBR. However, the accelera ted strength has an uncertainty that is described by the within-batch standard deviation, which was estimated from the differences between the accelerated strength s of pairs of LBR oven samples [52]. Assuming that the strengths measured on a flowable field mixture by the specific accelerated test method had a within-batch co efficient of variati on (COV) of 7.06%, the standard deviation, s at an average strength of 35. 67 LBR was 2.52 LBR. The 90% confidence interval for the average accelerat ed strength of the two LBR samples was as follows: 0.0535.6735.671.6452.520.707 2 35.672.93LBR s Z (5-20) where Z0.05 is the value from the standard normal distribution corresponding to 5% of the area under the curve. Thus, the 90% confid ence interval for the average accelerated strength was 32.74 to 38.60 LBR. Each di fferent measurement of accelerated strength produced a new confidence interval for the average 28-day strength. 5.3.6 Analysis on Other Samples Regression analysis was also performed on the remaining oven-dried samples. Figure 5-5 shows the accelerated strength plotted against the 28-day strength (LBR) regression graphs along with par tial regression analys is output. The pl ot represents the combined full oven-dried samples obtained for the study. At 2 days of oven curing, the correlation between accelerated strength a nd 28-day strength was fairly good (Figure 5-5). The accelerated strength was a pproximately 84.42% (R-squared value, R2) of the 28-day strength in LBR.

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126 y = 3.2039x0.8254 R2 = 0.84420.00 50.00 100.00 150.00 200.00 250.00 300.00 350.00 0.0050.00100.00150.00200.00250.00300.00 Accelerated curing strength, LBR28-day strength, LBR Figure 5-5. Accelerated curing vs. 28-day normal curing strength for all mixtures Further regression analysis was conducted using the 2-day oven dried samples with 56-day normal curing. Figure 5-6 illustrates the accelerated strength plots against the 56-day strength results. Like the 28-day corr elation, the 56-day correlation plot showed promising results. The coefficient of determination (R2-value) was 84.36 %. y = 3.8565x0.8316R2 = 0.84360.00 50.00 100.00 150.00 200.00 250.00 300.00 350.00 400.00 450.00 0.0050.00100.00150.00200.00250.00300.00 Accelerated curing strength, LBR56-day strength, LBR Figure 5-6. Accelerated curing vs. 56-day normal curing strength for all mixtures Using the accelerated curi ng data, a breakdown regressi on analysis was conducted on various mixtures with regard to their components and their influence on accelerated

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127 curing. The types of mix used were 20% fl y ash, 50% slag, and 0% mineral admixture. Table 5-3 provides a summary of regression equations along with the coefficient of determinations for accelerated 28and 56-day LBR strength. Table 5-3. Summary of regression equati ons for accelerated (oven) 28-day and 56-day LBR strength Type of Mix Estimated 28-day St rength Equation, LBR R-square 20% Fly Ash 0.9122.229 yx 0.876 50% Slag 0.7603.937 yx 0.863 0% Mineral Admixture 0.8702.857 yx 0.814 Combined 0.8443.857 yx 0.844 Type of Mix Estimated 56-day St rength Equation, LBR R-square 20% Fly Ash 0.9053.153 yx 0.907 50% Slag 0.7974.181 yx 0.842 0% Mineral Admixture 0.8573.434 yx 0.846 Combined 0.8253.204 yx 0.844 These correlations indicated that 2-day oven dried samples can be used to help estimate the long-term strength for flowable fi ll mixtures. It is also clear that the accelerated strength in LBR provided a meani ngful correlation for predicting the 28-day and 56-day long-term LBR strength. This was evident in their plot. The plots showed scattered data points with an increasing slope. It should be noted th at a power trend line was used for the two plots. Initially, the regre ssion plots used a linear fitted line, but this provided poor correlation result s. In response to the poor co rrelation, it was determined to use power trend to fit the regression pl ot, which resulted in the better fit. As the regression equation is used on a project, companion cylinders should be prepared along with cylinders for accelerated testing. The companion cylinders would be subjected to standard curing and tested for LBR strength at the designated age. The measured standard-cured strengths should be compared with the confidence intervals for

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128 the estimated strengths based on the compani on accelerated strengths. If the measured strengths constantly fall outside the estimated confidence intervals, the reliability of the regression line would be questionable. Th e new companion results should be added to the data set from the laboratory correlation testing to calculate a new regression line and its corresponding statistics. Th is new line should be used fo r later estimates of potential later-age strength. The making of compani on sets of accelerated and standard-cured cylinders should be continued until the measured strengths continue to fall within the corresponding calculated confidence intervals. Once the reliability of the procedure has been demonstrated, companion cylinders should be made at random intervals to reconfirm that the procedure continues to be reliable. 5.4 Model Validation and E valuation of Accuracy Ensuring the effectiveness of the regressi on models is an essential part of the findings and value of this study. In this se ction, the resultant out come for the response variables is evaluated to determine its validity for design purposes. Validation of a fitted regression equation demonstrates or confirms that the model is sound and effective for the purpose for which it was intended [40]. The intended purpose of the regression analysis in this research was to predict or estimate the values of the response variable precisely enough for engineers to use when designing flowable fill mixtures. 5.4.1 Varying Strength Prediction Models for Trend An analysis was made involving the regression models for the purpose of identifying characteristic trends. The foll owing steps were utilized for the analysis: 1. Create a matrix or table. 2. Vary the cement content: 0, 10, 20,, 200 (@ 10.0 lb/yd3 increments). 3. Vary the w/c ratio: 0.5, 1.5, 2.5,, 14.5 (@ 1.0 increments).

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129 4. Obtain the sand-to-water (s/w) ratio for each mix (see Appendix C). 5. Select mixtures with a ratio that is within 1.73 to 7.20 and label as feasible. 6. Compute estimated strength (LBR and ps i) and percent volume change values for feasible mixtures using 28-day and 56-d ay strength model equations at fixed designed air content and fixed pe rcent of mineral admixtures. From the matrix table the estimated 28 -day and 56-day strengths, along with percent volume change, were computed for thre e mixture criteria. The criteria were: 1) 15% fixed air content at 0% mineral admixture, 2) 8% fixed air content at 20% fly ash mineral admixture, and 3) 10% fixed air content at 50% gr ound granulated blast-furnace slag mineral admixture. Using the estimated strength and volume ch ange values, Figures 5-7 through 5-36 show the relationship of cement content and w/ c ratio versus streng th and percent volume change for the three selected mixture criter ia mentioned above. Based on the estimated strength values plotted against cement conten t and w/c ratio, the plots show increasing strength for increasing cement content and de creasing strength for increasing w/c ratio. This translated into the models showing mi xtures with high cement contents exhibiting higher strength and mixtures with high w/ c ratio exhibiting low strength. These identifiable trends demonstrated the pred ictability for the strength model equations developed from this study. Although the strength relationships displaye d in the figures identify trends, some show inaccurate tendencies. Pl ots are labeled with letters to help designate areas in the figures with identifiably inaccurate trends. The figures showing strength versus cement content and w/c ratio contain letters e f and g to identify the following: e = range of test population f = applicable range of prediction equation g = un-applicable range of prediction equation

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130 Figure 5-7. Estimated 28-day LBR strength vs. cement content at fixed air (15%) and fixed 0% mineral admixture Figure 5-8. Estimated 56-day LBR strength vs. cement content at fixed air (15%) and fixed 0% mineral admixture 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 180.00 200.00 050100150200250 Cement content, lbs/yd3Strength, LBR e f e g 0.00 50.00 100.00 150.00 200.00 250.00 050100150200250 Cement content, lbs/yd3Strength, LBR f e g

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131 Figure 5-9. Estimated 28-day compressive stre ngth vs. cement content at fixed air (15%) and fixed 0% mineral admixture Figure 5-10. Estimated 28-day compressive strength vs. cement content at fixed air (15%) and fixed 0% mineral admixture 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 050100150200250 Cement content, lbs/yd3Strength, psi e,f 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 180.00 050100150200250 Cement content, lbs/yd3Strength, psi f g e

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132 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 050100150200250 Cement content, lbs/yd3Volume change, % Minimum Mean Maximum Figure 5-11. Estimated volume change vs. cem ent content at fixed air (15%) and fixed 0% mineral admixture Figure 5-12. Estimated 28-day LBR strength vs. w/c ratio at fixed air (15%) and fixed 0% mineral admixture 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 180.00 0246810121416 w/c ratioStrength, LBR e, f g

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133 Figure 5-13. Estimated 56-day LBR strength vs. w/c ratio at fixed air (15%) and fixed 0% mineral admixture Figure 5-14. Estimated 28-day compressive st rength vs. w/c ratio at fixed air (15%) and fixed 0% mineral admixture 0.00 50.00 100.00 150.00 200.00 250.00 0246810121416 w/c ratioStrength, psi g e, f 0.00 50.00 100.00 150.00 200.00 250.00 300.00 0246810121416 w/c ratioStrength, LBR e, f g

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134 Figure 5-15. Estimated 56-day compressive st rength vs. w/c ratio at fixed air (15%) and fixed 0% mineral admixture 0.00 1.00 2.00 3.00 4.00 5.00 6.00 0246810121416 w/c ratioVolume change, % Minimum Mean Maximum Figure 5-16. Estimated volume change vs. w/ c ratio at fixed air (15%) and fixed 0% mineral admixture 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 050100150200250 Cement content, lbs/yd3Strength, psi e, f

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135 Figure 5-17. Estimated 28-day LBR strength vs. cement content at fixed air (8%) and fixed 20% fly ash mineral admixture Figure 5-18. Estimated 56-day LBR strength vs. cement content at fixed air (8%) and fixed 20% fly ash mineral admixture 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 180.00 200.00 050100150200250 Cement content, lbs/yd3Strength, LBR g f e 0.00 50.00 100.00 150.00 200.00 250.00 050100150200250 Cement content, lbs/yd3Strength, LBR e,f g

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136 Figure 5-19. Estimated 28-day compressive st rength vs. cement content at fixed air (8%) and fixed 20% fly ash mineral admixture Figure 5-20. Estimated 56-day compressive st rength vs. cement content at fixed air (8%) and fixed 20% fly ash mineral admixture 0.00 20.00 40.00 60.00 80.00 100.00 120.00 050100150200250 Cement content, lbs/yd3Strength, psi f g e 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 050100150200250 Cement content, lbs/yd3Strength, psi e,f

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137 0.00 0.50 1.00 1.50 2.00 2.50 050100150200250 Cement content, lbs/yd3Volume change, % Minimum Mean Maximum Figure 5-21. Estimated volume change vs. cem ent content at fixed air (8%) and fixed 20% fly ash mineral admixture Figure 5-22. Estimated 28-day LBR strength vs. w/c ratio at fixed air (8%) and fixed 20% fly ash mineral admixture 0.00 50.00 100.00 150.00 200.00 250.00 0246810121416 w/c ratioStrength, LBR g e,f

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138 Figure 5-23. Estimated 56-day LBR strength vs. w/c ratio at fixed air (8%) and fixed 20% fly ash mineral admixture Figure 5-24. Estimated 28-day compressive st rength vs. w/c ratio at fixed air (8%) and fixed 20% fly ash mineral admixture 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 180.00 0246810121416 w/c ratioStrength, psi g e,f 0.00 50.00 100.00 150.00 200.00 250.00 0246810121416 w/c ratioStrength, LBR g e,f

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139 Figure 5-25. Estimated 56-day compressive st rength vs. w/c ratio at fixed air (8%) and fixed 20% fly ash mineral admixture 0.00 0.50 1.00 1.50 2.00 2.50 3.00 0246810121416 w/c ratioVolume change, % Minimum Mean Maximum Figure 5-26. Estimated volume change vs. w/c ratio at fixed air (8 %) and fixed 20% fly ash mineral admixture 0.00 20.00 40.00 60.00 80.00 100.00 120.00 0246810121416 w/c ratioStrength, psi g e,f

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140 Figure 5-27. Estimated 28-day LBR strength vs. cement content at fixed air (10%) and fixed 50% ground granulated blastfurnace slag mineral admixture Figure 5-28. Estimated 56-day LBR strength vs. cement content at fixed air (10%) and fixed 50% ground granulated blastfurnace slag mineral admixture 0.00 50.00 100.00 150.00 200.00 250.00 050100150200250 Cement content, lbs/yd3Strength, LBR g f e 0.00 50.00 100.00 150.00 200.00 250.00 300.00 050100150200250 Cement content, lbs/yd3Strength, LBR g e,f

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141 Figure 5-29. Estimated 28-day compressive strength vs. cement content at fixed air (10%) and fixed 50% ground granulated blast-furnace slag mineral admixture Figure 5-30. Estimated 56-day compressive strength vs. cement content at fixed air (10%) and fixed 50% ground granulated blast-furnace slag mineral admixture 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 050100150200250 Cement content, lbs/yd3Strength, psi e,f 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 050100150200250 Cement content, lbs/yd3Strength, psi g f e

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142 0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 050100150200250 Cement content, lbs/yd3Volume change, % Minimum Mean Maximum Figure 5-31. Estimated volume change vs. cem ent content at fixed air (10%) and fixed 50% ground granulated blast-furnace slag mineral admixture Figure 5-32. Estimated 28-day LBR strength vs. w/c ratio at fixed air (10%) and fixed 50% ground granulated blast-furnace slag mineral admixture 0.00 50.00 100.00 150.00 200.00 250.00 0246810121416 w/c ratioStrength, LBR g e,f

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143 Figure 5-33. Estimated 56-day LBR strength vs. w/c ratio at fixed air (10%) and fixed 50% ground granulated blast-furnace slag mineral admixture Figure 5-34. Estimated 28-day compressive st rength vs. w/c ratio at fixed air (10%) and fixed 50% ground granulated blastfurnace slag mineral admixture 0.00 50.00 100.00 150.00 200.00 250.00 300.00 0246810121416 w/c ratioStrength, LBR g e,f 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 180.00 0246810121416 w/c ratioStrength, psi g e,f

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144 Figure 5-35. Estimated 56-day compressive st rength vs. w/c ratio at fixed air (10%) and fixed 50% ground granulated blastfurnace slag mineral admixture 0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 0246810121416 w/c ratioVolume change, % Minimum Mean Maximum Figure 5-36. Estimated volume change vs. w/ c ratio at fixed air (10%) and fixed 50% ground granulated blast-furnace slag mineral admixture 0.00 50.00 100.00 150.00 200.00 250.00 300.00 0246810121416 w/c ratioStrength, psi g e,f

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145 The letters e f and g were inserted into the charts in order to provide a visual context for areas where the prediction equatio ns grossly estimate and underestimate the strength. For example, Figure 5-12 shows th e estimated 28-day LBR strength versus w/c ratio at fixed 15% air content and fixed 0% mineral admixtur e. The plot area labeled g specifies the region where the prediction equati on overestimates the strength. The plots help to illustrate and define areas to avoid when using the prediction models. Plots which display percent volume change versus w/c ratio and cement content do not contain any letters, instead these figures contain lines to indicate the minimum, mean and maximum of the overall estimated percent volume change. This approach allows for one to better examine the estimated values from a lowand high-end perspective due to the lack of identifiable trends in volume change plots. 5.4.2 Comparison of Strength Prediction Models A comparison was made between the streng th prediction models developed from the NCHRP studies on flowable fill and the regression models formed from this dissertation research. Table 5-4 summarizes the NCHRPs mixture proportions used in their study. In comparing the two models, it wa s important to identify mixtures that were similar in design. The design in this case meant mixtures that included concrete sand (silica sand) as fines aggregates and 0% mine ral admixtures (no fly ash), and into which air-entrainment was introduced during batching. In Chapter 2, it was specified that the NCHRP study formed two models for estimati ng the compressive strength of flowable fill, and those were air-entrained and nonair-e ntrained models. For this comparison, the NCHRPs air-entrained model was utilized. This made for a fair comparison between models due to the fact that the flowable fill mixtures used to desi gn the models for this research study were all entirely air-entra ined mixes. The following NCHRP mixtures

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146Table 5-4. NCHRPs CLSM mixture proportions and fresh properties [38] Cement Content Mixture No.a (kg/m3) (lbs/yd3) Fly Ash Type Fly Ash Content (kg/m3) Fine Aggregate Type Water Demand (kg/m3) Flow (cm) Total Bleeding (%) Air Content (%) Fresh Unit Weight (kg/m3) W/C Ratio 1 30 51 Class C 180 Concrete sand 211 20 NA 0.9 1965 7.0 2 60 101 Class C 180 Concrete sand 206 20 2.45 1 2108 3.4 1R 30 51 Class C 180 Concrete sand 206 12 2.08 0.9 1974 6.9 15 30 51 Class C 360 Foundry sand 486 20 0.13 2.8 1741 16.2 3 60 101 Class C 360 Bottom ash 577 17.8 4.32 1.7 1754 9.6 8 60 101 High carbon 180 Foundry sand 532 24.1 1.04 3.3 1647 8.9 10 30 51 High carbon 180 Bottom ash 628 14 4.81 2 1681 20.9 9 60 101 Class F 360 Foundry sand 520 20 0.54 2.5 1684 8.7 5 60 101 Class F 180 Bottom ash 600 17.8 5.84 2.5 1739 10.0 12 30 51 Class C 360 Bottom ash 572 21.6 3.64 2.7 1774 19.1 4 30 51 Class F 360 Concrete sand 220 20 0.39 2.2 2199 7.3 7 30 51 Class F 180 Foundry sand 501 20 0.57 2.1 1817 16.7 3R 60 101 Class C 360 Bottom ash 541 20 2.58 2.1 1997 9.0 4R 30 51 Class F 360 Concrete sand 220 21.6 2.92 1.8 2211 7.3 24 60 101 Class F 1200 None 486 24 2.25 2.8 1635 8.1 23 60 101 None 0 Bottom ash 454 14 1.3 28.5 1382 7.6 18 60 101 None 0 Concrete sand 200 21.6 0.7 16.5 1826 3.3 14 60 101 Class F 360 Concrete sand 216 21.6 1 1.3 2174 3.6 2R 60 101 Class C 180 Concrete sand 206 25 0.21 0.5 2291 3.4 29 60 101 Foundry sand 0 None 373 23 0.28 2.6 1812 6.2 30 30 51 Foundry sand 0 None 414 20 0.4 2 1789 13.8 17* 30 51 None 0 Bottom ash 582 12.7 4.35 20 1447 19.4 11 60 101 High carbon 360 Bottom ash 573 23 6.42 1.7 1743 9.6 6 30 51 High carbon 360 Concrete sand 315 20 2.26 1.3 2103 10.5 16 30 51 None 0 Concrete sand 295 20 2.33 16 1922 9.8 21 30 51 None 0 Concrete sand 170 18 0.62 25.5 1789 5.7 22 60 101 None 0 Concrete sand 131 20 0.05 26.5 1748 2.2 22R 60 101 None 0 Concrete sand 136 18 0.43 25.5 1802 2.3 5R 60 101 Class F 180 Bottom ash 600 16 7.2 1.4 1887 10.0 26* 60 101 None 0 Concrete sand 136 16.5 0 25.5 1802 2.3 16R 30 51 None 0 Concrete sand 295 19.1 2.35 15.5 1874 9.8 13 60 101 Class C 360 Foundry sand 499 20 0 1.8 1902 8.3 25 60 101 High carbon 1200 None 853 24 7.38 1.3 1322 14.2 19* 30 51 None 0 Bottom ash 492 13 1.08 25 1385 16.4 20* 60 101 None 0 Bottom ash 525 13 3.41 18.5 1485 8.8 27 60 101 Class C 1200 None 486 23 1.28 0.7 1638 8.1 20R 60 101 None 0 Bottom ash 525 13 1.44 15.5 1511 8.8 28 30 51 Class F 180 Concrete sand 220 20 1.33 1.4 2182 7.3 Note: aR = mixtures that were replicated for statistical purposes; = mixtures batched for a third time due to malfunctions during batching or testing

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147 used to compare the models were: 16, 21, 22, 22r, 26*, and 16r. Using NCHRPs model (Equation 2-7) and the 28-day compressive streng th model formulated in this dissertation, the required values for the variables were entered and the estimated compressive strength from both models, shown in Table 5-5, were pl otted in Figure 5-37 a nd correlated with Table 5-5. Comparison of the NCHRP measur ed and predicted 28-day strength for airentrained mixtures streng th prediction model Confidence, 95% Mixture No. Measured Strength (psi) NCHRP Strength (psi) Dissertation Strength (psi) Lower (psi) Upper (psi) 16 18.85 16.49 26.83 13.84 39.83 21 23.20 45.45 18.67 5.93 31.41 22 105.85 106.09 97.82 84.83 110.81 22ra 139.20 103.96 94.60 81.60 107.59 26b 165.30 103.96 94.60 81.60 107.59 16ra 21.75 16.49 26.28 13.29 39.27 Note: amixtures that were replicated for statistical purposes; and bmixture batched for a third time due to malfunctions during batching or testing R2 Dissertation = 0.90 R2 NCHRP = 0.860 20 40 60 80 100 120 140 0.0020.0040.0060.0080.00100.00120.00140.00160.00180.00 Measured Strength, psiPredicted Strength, psi NCHRP Dissertation Linear (Dissertation ) Linear (NCHRP) Figure 5-37. Comparison of measured and predicted 28-days strength

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148 the measured compressive strength for the six flowable fill mixtures. Both models yielded very good correlation in predicting 28day compressive strength. The models from the NCHRP and this research study yielded, respectively, R2 values of 0.86 and 0.90. A second effort was undertaken to compar e the formulated dissertation regression models with other published flowable fill strength prediction models. The two strength prediction models used are Equation 2-6 by Bhat and Equation 2-7 by NCHRP. The approach utilized to compare the mo dels entails varying the w/c ratio ( c ), holding the cement content ( a ), air content ( b ) and mineral admixture ( d ) fixed. The fixed values used for cement content, air content and mineral admixtures were, respectively, 100 lb/yd3, 15% and 0%. This provided an estima ted 28-day compressive strength for all three prediction equations. Table 5-6 shows a comparison of estimated 28-day compressive strength for the three prediction models. Figures 5-38 and 5-39 provide a more il lustrative comparison of the estimated compressive strength from the models. From the table and figures, the formula developed by Bhat estimate the 28-day comp ressive strength much higher than the other two models; whereas, the disse rtation and NCHRP models estimate the 28-day compressive strength at lo wer approximations. When comparing the strength estimation of the dissertation to the NCHRPs, the predictive formula of the dissertation estimates the compressive strength slightly lower than the NCHRP formula. Based on this information, one can conclude that a slight improvement exists with using the dissertation model for estimating the 28-day compressive strength.

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149 Table 5-6. Comparison of estimat ed 28-day compressive strength Bhat Model NCHRP Model Dissertation Model W/C Ratio Strength (MPa) Strength (psi) Strength (MPa) Strength (psi) Strength (MPa) Strength (psi) 2.0 16.24 2355 0.76 111 0.76 110 2.2 12.29 1783 0.73 106 0.71 103 2.4 9.55 1386 0.69 101 0.66 96 2.6 7.59 1101 0.66 96 0.62 90 2.8 6.16 893 0.63 91 0.58 84 3.0 5.07 736 0.60 87 0.54 78 3.2 4.25 616 0.57 83 0.50 72 3.4 3.60 523 0.54 79 0.46 67 3.6 3.09 449 0.52 75 0.43 62 3.8 2.69 390 0.49 72 0.40 58 4.0 2.36 342 0.47 68 0.37 53 4.2 2.09 303 0.45 65 0.34 49 4.4 1.86 270 0.43 62 0.31 45 4.6 1.68 243 0.41 59 0.28 41 4.8 1.52 221 0.39 56 0.26 38 5.0 1.39 201 0.37 53 0.24 35 5.2 1.28 185 0.35 51 0.22 32 5.4 1.18 171 0.33 48 0.20 29 5.6 1.10 159 0.32 46 0.19 27 5.8 1.02 149 0.30 44 0.17 25 6.0 0.96 139 0.29 42 0.16 23 6.2 0.91 131 0.28 40 0.15 22 6.4 0.86 124 0.26 38 0.14 21 6.6 0.82 118 0.25 36 0.14 20 6.8 0.78 113 0.24 34 0.13 19 7.0 0.74 108 0.23 33 0.13 19 7.2 0.71 104 0.22 31 0.13 19 7.4 0.69 100 0.21 30 0.13 19 7.6 0.66 96 0.20 28 0.13 19 7.8 0.64 93 0.19 27 0.14 20 8.0 0.62 90 0.18 26 0.14 21

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150 0 500 1000 1500 2000 2500 0123456789 w/c ratioStrength, psi NCHRP's Model Dissertation's Model Bhat's Model Figure 5-38. Comparison of estimated 28-da y compressive strength for Bhat, NCHRP, and dissertation models 0 20 40 60 80 100 120 0123456789 w/c ratioStrength, psi NCHRP's Model Dissertation's Model Figure 5-39. Comparison of estimated 28day compressive strength for NCHRP and dissertation models 5.4.3 Mixture Design Examples to Validate Models In this section, the design of 11 validation flowable fill mixtures is discussed. After designing and batching the mixtures in the la boratory, the exact air content was used along with other design parameters to estimat e the LBR strength, compressive strength and percent volume change for each mixture. The validation flowable fill mixtures were

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151 designed using the volumetric method discussed in Chapter 3. The following outlines the two steps used for designing 1-yd3 mixtures. Step 1: Determine the amount of mate rials required for mixtures with the following design criteria: a. Mix #1v i. cementitious content = 195 lb/yd3 ii. w/c = 2.25 iii. air content = 8.5 2.5% iv. mineral admixtures = 50% slag b. Mix #2v i. cementitious content = 69 lb/yd3 ii. w/c = 6.0 iii. air content = 15.5 2.5% iv. mineral admixtures = 20% fly ash c. Mix #3v i. cementitious content = 165 lb/yd3 ii. w/c = 3.0 iii. air content = 10.0 2.5% iv. mineral admixtures = 0% The following are known properties for the materials that will be used to create the mixtures: Sc = 3.15 specific gravity of cement Ss = 2.42 specific gravity of slag Sf = 2.36 specific gravity of fly ash Sag = 2.63 specific gravity of fine aggregate N = 3.00 percent of natural moisture content for fine aggregate L = 0.40 percent absorption for fine aggregate Solution for Mix #1v 1. Calculate weight of cement, lb/yd3. cementitiouscontent 1950.5097.50wpCS

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152 2. Calculate weight of slag, lb/yd3. cementitiouscontent 19597.5097.50wwSC 3. Calculate weight of water, lb/yd3. w/cratio 2.2597.5097.50438.75wwwWCS 4. Calculate absolute volume of cement, ft3/yd3. 397.50 0.496ft 62.43.1562.4w v cC C S 5. Calculate absolute volume of slag, ft3/yd3. 397.50 0.646ft 62.42.4262.4w v sS S S 6. Calculate absolute volume of water, ft3/yd3. 3438.75 7.031ft 62.462.4w vW W 7. Calculate absolute volume of target air content, ft3/yd3. 327 8.527 2.295ft 100100p vA A 8. Calculate total absolute volume of known ingredients 310.468ftvvvvCSWA 9. Calculate absolute volume of satura ted-surface-dry (SSD) fine aggregates, ft3/yd3. 327()16.532ftvsvvvvFACSWA 10. Calculate weight of saturated-su rface-dry fine aggregates, lb/yd3. 62.4 16.5322.6362.42713.10wsvsagFAFAS

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153 11. Calculate the sand-to-water (s/w) ra tio (s/w ratio range 1.73 7.20). 2713.10 6.184 438.75ws wFA S WW 12. Calculate weight of fine aggregate based on natural moisture content, lb/yd3. 1 1 10.03 2713.102783.36 10.004wnwsN FAFA L 13. Correct the weight of water content due to percentage of moisture difference, lb/yd3. 2783.362713.1070.26 438.7570.26509.01wswn wWFAFA WWW W Table 5-7 provides a summary of material s required for the eleven validation mixtures. The bold face values are the weight amounts for the cement, slag, fly ash, sand, and water needed for batching each mix. The sand-to-water ratio shown for the three mixtures fall within the r ecommended specified feasible mixture sandto-water ratio range of 1.73 to 7.20. After obtaining the batching informati on and ensuring the mixtures met the sand-to-water ratio criteria for the three mixtures, the three validation mixtures were batched. Table 5-8 shows the plas tic properties for th e batched validation mixtures. In accordance to their design, a ll mixes achieved (exact) air within their respective designed target air content. Step 2: Determine the 28-day strength and the percent volume change using the mixture parameters. Solution : The 28-day and 56-day strengths of flowable fill and the percent volume change can be estimated by using Equations 5-3 through 5-7. When estimating the

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154Table 5-7. Summary of materials required for validation mixtures Per 1.0 cu. yd. Batch Mix No.a Cement Content (lb/yd3) W/C Ratio Mineral Admixtures (%) Target Air Content ( 2.5%) Cw (lbs) Sw (lbs) Fw (lbs) Ww (lbs) Cv Sv Fv Wv Av FAvs FAws (lbs) S/W FAwn W W 1v 195 2.25 50 8.50 97.50 97.50 0.00438.750.50 0.65 0.00 7.03 2.30 16.53 2713.11 6.18 2783.37 70.26 509.01 2v 69 6.00 20 15.50 55.20 0.00 13.80414.000.28 0.00 0.09 6.63 4.19 15.81 2594.31 6.27 2661.49 67.18 481.18 3v 165 3.00 0 10.00 165.00 0.00 0.00495.000.84 0.00 0.00 7.93 2.70 15.53 2548.31 5.15 2614.30 65.99 560.99 4v 60 7.50 50 10.50 30.00 30.00 0.00450.000.15 0.20 0.00 7.21 2.84 16.60 2724.62 6.05 2795.17 70.56 520.56 5v 90 5.50 50 10.50 45.00 45.00 0.00495.000.23 0.30 0.00 7.93 2.84 15.71 2577.44 5.21 2644.19 66.75 561.75 6v 70 9.50 20 6.00 56.00 0.00 14.00665.000.28 0.00 0.09 10.66 1.62 14.35 2354.24 3.54 2415.21 60.97 725.97 7v 80 6.50 20 6.00 64.00 0.00 16.00520.000.33 0.00 0.11 8.33 1.62 16.62 2726.74 5.24 2797.35 70.61 590.61 8v 110 4.50 20 6.00 88.00 0.00 22.00495.000.45 0.00 0.15 7.93 1.62 16.85 2765.93 5.59 2837.56 71.63 566.63 9v 60 7.50 0 15.00 60.00 0.00 0.00450.000.31 0.00 0.00 7.21 4.05 15.43 2532.78 5.63 2598.36 65.59 515.59 10v 100 4.50 0 15.00 100.00 0.00 0.00450.000.51 0.00 0.00 7.21 4.05 15.23 2499.38 5.55 2564.10 64.72 514.72 11v 130 3.50 0 15.00 130.00 0.00 0.00455.000.66 0.00 0.00 7.29 4.05 15.00 2461.18 5.41 2524.92 63.74 518.74Per 5.5 cu. ft. Batch Mix No. a Cement Content (lb/yd3) W/C Ratio Mineral Admixtures (%) Target Air Content ( 2.5%) Cw (lbs) Sw (lbs) Fw (lbs) Ww (lbs) Cv Sv Fv Wv Av FAvs FAws (lbs) S/W FAwn W W 1v 195 2.25 50 8.50 19.8619.86 0.00 89.380.10 0.13 0.00 1.43 0.47 3.37 552.67 1.26 566.98 14.31 103.69 2v 69 6.00 20 15.50 11.24 0.00 2.81 84.330.06 0.00 0.02 1.35 0.85 3.22 528.47 1.28 542.16 13.69 98.02 3v 165 3.00 0 10.00 33.61 0.00 0.00100.830.17 0.00 0.00 1.62 0.55 3.16 519.10 1.05 532.54 13.44 114.28 4v 60 7.50 50 10.50 6.11 6.11 0.00 91.670.03 0.04 0.00 1.47 0.58 3.38 555.01 1.23 569.39 14.37 106.04 5v 90 5.50 50 10.50 9.17 9.17 0.00100.830.05 0.06 0.00 1.62 0.58 3.20 525.03 1.06 538.63 13.60 114.43 6v 70 9.50 20 6.00 11.41 0.00 2.85135.460.06 0.00 0.02 2.17 0.33 2.92 479.57 0.72 491.99 12.42 147.88 7v 80 6.50 20 6.00 13.04 0.00 3.26105.930.07 0.00 0.02 1.70 0.33 3.38 555.45 1.07 569.83 14.38 120.31 8v 110 4.50 20 6.00 17.93 0.00 4.48100.830.09 0.00 0.03 1.62 0.33 3.43 563.43 1.14 578.02 14.59 115.42 9v 60 7.50 0 15.00 12.22 0.00 0.00 91.670.06 0.00 0.00 1.47 0.83 3.14 515.94 1.15 529.30 13.36 105.03 10v 100 4.50 0 15.00 20.37 0.00 0.00 91.670.10 0.00 0.00 1.47 0.83 3.10 509.13 1.13 522.32 13.18 104.85 11v 130 3.50 0 15.00 26.48 0.00 0.00 92.690.13 0.00 0.00 1.49 0.83 3.05 501.35 1.10 514.33 12.98 105.67 Note: a v = denotes validation mix

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155 Table 5-8. Summary of plastic properties of validation mixture models Air Content Batch Mix No. AEA (ml) Flow (in.) Target (%) Achieved (%) Unit Weight (lb/t3) Mixture Temperature ( F) 1v 25 5.50 8.5 2.5 11.00 113.04 75.00 1vr 40 5.50 8.5 2.5 10.50 113.92 77.00 2v 40 0.00 15.5 2.5 16.00 106.40 75.00 2vr 40 0.00 15.5 2.5 14.00 109.28 77.00 3v 45 8.00 10.5 2.5 7.60 119.36 80.00 3vr 45 8.00 10.5 2.5 7.70 117.36 80.00 4v 50 5.50 10.5 2.5 9.50 101.04 74.00 5v 25 4.50 10.5 2.5 11.00 113.16 74.00 6v 25 0.00 6.0 2.5 5.00 124.24 72.00 7v 30 0.00 6.0 2.5 9.75 116.88 74.00 8v 30 4.50 6.0 2.5 8.50 119.04 74.00 9v 40 5.50 15.0 2.5 14.70 106.56 72.00 10v 40 5.50 15.0 2.5 14.70 107.92 75.00 11v 50 5.50 15.0 2.5 12.75 110.96 75.00 Note: r = denotes repeat responses, the designed air or achieved (exa ct) air content for the mixture can be used. It is recommended to use the achie ved air content as o pposed to the designed air content. The designed air can be used for preliminary design, so as to get an approximate estimated strength for a particular flowable fill mixture prior to batching. 2 28dayLBR 22 299.0400.92818.78024.8173.2140.000756 1.1870.07920.03370.1450.00426 1.1500.03040.114 y abcda cdabacad bcbdcd 56dayLBR 222 917.4234.02933.638129.9301.767 0.008404.9640.06010.09190.359 0.003732.6020.03750.186 yabcd acdabac adbcbdcd 2 28daypsi 22 94.9341.5230.68145.6161.2300.00294 3.3650.02720.009640.06350.0100 0.2320.04180.145 y abcda cdabacad bcbdcd

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156 2 56daypsi 22 152.8310.24414.1301.5071.4150.00135 1.2150.02890.05270.01300.000565 1.1440.004190.0103 yabcda cdabacad bcbdcd %volumechange 222 3.9450.004570.1930.6670.0284 0.00001050.03730.0001850.000116 0.009040.00007000.01280.000165 0.00445 yabcd acdab acadbcbd cd For Mix #1v: 28dayLBR 222 299.0400.928(195)18.780(8.5)24.817(2.25) 3.214(50)0.000756(195)1.187(2.25)0.0792(50) .0337(1958.5)0.145(1952.25)0.00426(19550) 1.150(8.52.25)0.0304(8.550)0.114(2.2550) y 28dayLBR 251.978LBR y 56dayLBR 222 917.4234.02919533.6388.5129.9302.25 1.767500.008401954.9642.250.060150 0.09191958.50.3591952.250.0037319550 2.6028.52.250.03758.5500.1862.2550 y 56dayLBR 278.348 y LBR 28daypsi 222 94.9341.523(195)0.681(8.5)45.616(2.25)1.230(50) 0.00294(195)3.365(2.25)0.0272(50) 0.00964(1958.5)0.0635(1952.25)0.0100(19550) 0.232(8.52.25)0.0418(8.550)0.145(2.2550) y 28daypsi 147.135psiy 56daypsi 222 152.8310.24419514.1308.51.5072.251.41550 0.001351951.2152.250.0289500.05271958.5 0.01301952.250.000565195501.1448.52.25 0.004198.5500.01032.2550y 56daypsi 137.411ypsi

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157 %volumechange 22 2 3.9450.00457(195)0.193(8.5)0.667(2.25) 0.000185(50)0.0284(50)0.0000105(195) 0.0373(2.25)0.000116(1958.5)0.00904(1952.25) 0.0000700(19550)0.0128(8.52.25) 0.000165(8.550 y )0.00445(2.2550) %volumechange 0.3835%y Tables 5-9 and 5-10 sh ow summaries of estimated 28-day and 56-day strength and percent volume change for the validation mixes 1v through 6v and 7v through 11v, respectively. The tables also show a comparison between the experimental results and the es timated (calculated) results. The results of the predicted (estimated ) and measured strengths for validating the mixtures of the model are plotted and correlated in Figures 5-40 through 5-42. The R2 values for the 28-day LBR strengt h, 28-day compressive strength, and 28-day oven strength results, respecti vely, are 0.864, 0.916, and 0.868. 5.5 Summary of Model Equations and Limitations Table 5-11 summarized the recommended pr edictive formulas developed in this study. The table also lists the variables al ong with their applicable ranges. To help determine the suitable ra nge for cement content (a), air content (b) and w/c ratio (c), a succession of plots were generated by vary ing the variables and estimating LBR and compressive strength. The estimated strength was plotted and analyzed, the applicable range was later selected after extensive eval uation. Appendix D shows plots of estimated 28and 56-day strength using applicable ranges of predicti on equation variables.

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158 Table 5-9. Comparison of estimated and experimental results for batch mixes 1v through 6v 95% Confidence Results Batch Mix No. Testing Interval Lower Upper Estimated Experimentala Estimated Strength (Oven)b 28-day strength, LBR 226 278 252 216 220 28-day strength, psi 134 160 147 101 -56-day strength, LBR 249 307 278 223 273 56-day strength, psi 121 153 137 100 -1v 24-hr volume change, % -0.93 0.16 2.52 NR -28-day strength, LBR -23 28 3 25 35 28-day strength, psi -14 12 -1 13 -56-day strength, LBR -10 48 19 29 43 56-day strength, psi 5 37 21 16 -2v 24-hr volume change, % 0.20 1.29 0.75 NR -28-day strength, LBR 173 224 198 180 269 28-day strength, psi 99 125 112 99 -56-day strength, LBR 204 262 233 238 335 56-day strength, psi 109 141 125 138 -3v 24-hr volume change, % -0.02 1.07 0.52 NR -28-day strength, LBR 61 112 86 13 18 28-day strength, psi 24 11 37 17 -56-day strength, LBR 60 119 89 12 22 56-day strength, psi 32 64 48 15 -4v 24-hr volume change, % -1.88 -0.79 -1.34 NR -28-day strength, LBR 78 130 104 55 81 28-day strength, psi 33 59 46 32 -56-day strength, LBR 100 158 129 NR 100 56-day strength, psi 53 85 69 NR -5v 24-hr volume change, % -0.77 0.32 -0.22 0.65 -28-day strength, LBR 25 76 51 51 93 28-day strength, psi -4 22 9 20 -56-day strength, LBR 39 98 69 75 115 56-day strength, psi -3 29 13 31 -6v 24-hr volume change, % -0.65 0.44 -0.11 NR -aNR = Not recorded b-= No data

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159 Table 5-10. Comparison of estimated and experimental results for batch mixes 7v through 11v 95% Confidence Results Batch Mix No. Testing Interval Lower Upper Estimated Experimentala Estimated Strength (Oven)b 28-day strength, LBR 21 75 50 13 49 28-day strength, psi -9 17 4 13 -56-day strength, LBR 46 104 75 NR 60 56-day strength, psi 30 62 46 NR -7v 24-hr volume change, % -0.47 0.62 0.07 0.50 -28-day strength, LBR 76 127 101 64 132 28-day strength, psi 33 59 46 27 -56-day strength, LBR 110 168 139 NR 164 56-day strength, psi 57 89 73 NR -8v 24-hr volume change, % -0.70 0.39 -0.16 1.51 -28-day strength, LBR 22 74 48 23 47 28-day strength, psi -12 14 1 14 -56-day strength, LBR 16 75 46 NR 57 56-day strength, psi 18 50 34 NR -9v 24-hr volume change, % 0.59 1.68 1.14 0.88 -28-day strength, LBR 55 107 81 23 97 28-day strength, psi 30 56 43 35 -56-day strength, LBR 59 118 89 NR 120 56-day strength, psi 46 78 62 NR -10v 24-hr volume change, % 0.50 1.59 1.05 1.01 -28-day strength, LBR 111 162 136 96 135 28-day strength, psi 69 95 82 57 -56-day strength, LBR 115 174 145 NR 168 56-day strength, psi 72 104 88 NR -11v 24-hr volume change, % 0.17 1.26 0.72 3.16 -aNR = Not recorded b-= No data

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160 Figure 5-40. Comparison of measured and predicted 28-da y LBR strength of validation mixtures of model R2 = 0.9160.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 020406080100120 Measured Strength, psiPredicted Strength, psi Figure 5-41. Comparison of measured and predicted 28-da y compressive strength of validation mixtures of model R2 = 0.864 0.00 50.00 100.00 150.00 200.00 250.00 300.00 0.0050.00100.00150.00200.00250.00 Measured Stren g th LBRPredicted Strength, LBR

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161 R2 = 0.8680.00 50.00 100.00 150.00 200.00 250.00 300.00 0.0050.00100.00150.00200.00250.00 Measured Strength, LBRPredicted Strength, LBR Figure 5-42. Comparison of measured and predicted 28-da y (oven) LBR strength of validation mixtures of model One of the objectives of this research study was to vary mixture components to predict shrinkage (percent volume change) as they occur in flowable fill using a prediction equation. A model equation was developed, however due to the variation that exists in the laboratory data, it was c oncluded not to recommend the percent volume change regression equation for use. As a result, it is excluded in the summary of recommended equations shown in Table 5-11. The use of the prediction equations presen ts an alternative for one to use when designing a flowable fill mixture. Consistent use of the formula will enhance and provide engineers needed information on long-term st rength of a mix prior to batching. The benefits of such a tool, alt hough small, nonetheless play an important role for those who use flowable fill in their construction operations. Alt hough these equations contain what is perceived to be a good co efficient of determination (c orrelation), exemplary caution should be used when there are utilized. This implies that the applic ation of the equations does not negate a users responsibilit y to exercise caution and good judgment.

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162 Table 5-11. Summary of r ecommended strength predic tion equations listed with variables and range Summary of Strength and Percent Volume Change Prediction Equations 2 28dayLBR 22 299.0400.92818.78024.8173.2140.000756 1.1870.07920.03370.1450.00426 1.1500.03040.114 y abcda cdabacad bcbdcd 2 28daypsi 22 94.9341.5230.68145.6161.2300.00294 3.3650.02720.009640.06350.0100 0.2320.04180.145 y abcda cdabacad bcbdcd 2 56dayLBR 22 917.4234.02933.638129.9301.7670.00840 4.9640.06010.09190.3590.00373 2.6020.03750.186 y abcda cdabacad bcbdcd 2 56daypsi 22 52.8310.24414.1301.5071.4150.00135 1.2150.02890.05270.01300.000565 1.1440.004190.0103 y abcda cdabacad bcbdcd Variables (range) a b c d where, a = cement content, lb/yd3 b = air content, % c = w/c ratio d = mineral admixtures [i.e., 0%, 20% fly ash, and 50% slag]; 75 200 2.0 15.0 2.0 9.0 0%, 20% and 50% Note(s): (i) Estimated low strength and negative va lues should be use with cautions. (ii) Avoid using values falling outside of variab les range; when using equation, use only applicable variable range. For field applications, the mathematical m odel equations presented in this research are intended to provide guidelines for developi ng a mixture to ensure future excavation of flowable fill or to ensure that a minimum strength is obtained to meet a design specification. It should be noted that the derived equations do have limitations. Due to the nature of the study, the author can only ensure the validity of the equations with the materials used in this study. Moreove r, in using the mathematical model equations, special limitations are associated with their usage. This implies that when using the models, one

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163 should stay within the parameters for all four factors. For ex ample, if using the models to estimate the strength for flow able fill, the recommended pa rameters for each factor (as shown in Table 5-11) must be selected, i.e ., a cement content within the range of 75 to 200 lb/yd3; a w/c ratio in the range of 2.0 to 9.0; an air content (if possible to achieve) within the range of 2.0 to 15.0%; and the following ot her ingredients at their recommended percentages: gr ound blast furnace slag at 50%, fly ash at 20% and mineral admixtures at 0%. Ensuring these factors fall within these parameters will enhance an accurate prediction using the equations. For some cases when using the equation models, a negative response may be obtained. It is not apparent why this happens. A possible explanation for this could be due to the least square method that was employed to estimate the regres sion coefficients. The methods of least squares chooses the s in the model equations so that the sum of squares for the errors, is minimized. Another expl anation for seeing a negative response could be based on the fact that a mixture does not fall within the models constraints or the mixture being design is not feasible. In the event that a negative response is obtained, it is best to avoid such a mix and se lect one which gives a more suitable or confident response.

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164 CHAPTER 6 SUMMARY, CONCLUSIONS AND RECOMMENDATIONS 6.1 Summary The construction industry searches for the most cost and time efficient means for completing its projects. To help in this matte r, newer forms of cons truction material have been introduced. The most common is contro lled low strength material (CLSM), also known as flowable fill. Flowable fill is an extremely versat ile construction material that has been used in a wide variety of applic ations. Flowable fill offers a number of advantages over conventional earthfill materi als that require controlled compaction in layers. One requirement typically encountered for flowable fill is the need to limit the maximum compressive strength. To predict the long-term strength and the excavatability of flowable fill using conventional excavating equipment, many approaches can be employed. For predicting whether or not a fl owable fill mix is excavatable, one approach is to develop a correlation using the early age strength and long-term strength of the mixture. Equipped with this knowledge, the main fo cus of this research was to design a method for determining long-term strength fo r future excavation by introducing a newer terminology describing flowab le fill strength, and es timate the volume change (shrinkage) using prediction models. A labor atory test program was developed to meet the stated objectives. A 4 3 2 3 factorial design matrix (4 levels cement, 3 levels mineral admixtures, 2 levels air content, and 3 levels w/c ratio) was employed to evaluate the strength and shrinkage of flowable fill. The design matrix summed up to a total of 72

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165 mixture combinations including replicates. A method of uti lizing the sand-to-water ratio was devised to select mixtures from the matrix that were feasible. The process narrowed the total number of feasible mixtur es for batching from 72 to 58. Before conducting the laboratory work, trial testing was planned. A trial mix was prepared and samples were taken to test fo r unconfined compressive strength, LBR, and for measuring sample strengths ut ilizing a proctor penetrometer. Pre-planning included identif ying a process for preparing samples; selecting proper equipment for measuring the behavior of the materials, such as volume change (shrinkage); and designating a location for storing both oven and normal cured samples. Two mixes were formulated for each day of mixing making a total of 58 mixes. In each mix, 33 samples (15 plastic cylinders and 18 LBR molds) were prepared. Tests were conducted on set time, flow, volume change, LBR strength, compre ssive strength and other flowable fill properties, such as unit-weight and air content. Three different methods for measuring volume change (shrinkage) in flowable fill were evaluated. These three methods included: (1) a method similar to the one used to measure free shrinkage in concrete (ASTM C1 57); (2) the dial gauge method used for measuring the percent change in volume, and (3) a method involving measuring height differences of the 24-hr, 4-in. 8-in. unconfined compressive strength specimens. Shrinkage measurement using these three methods was made on all batch mix combinations used in this study. Comparing the data obtained from all three methods, the one providing the most relia ble data was the second me thod. Thus, method 2 was adopted for use in the laboratory test program for this study.

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1666.2 Conclusions With the study objective in mind, the following conclusions are derived. Laboratory strength results for 3-, 28-, and 56-day LBR samples varied from 1.00 LBR to 289.67 LBR. Similarly, the compressive st rengths recorded fo r 3-, 28-, and 56-day samples varied from 1.17 psi to 162.10 psi. The 24-hr volume change results ranged from 0.14 % to 3.89 %. After 6 hours, the labor atory results of penetr ation resistance for all mixtures ranged from 0.00 to 50.67 psi. The recommended penetration resistance value obtained from the literature search wa s 65 psi. Mixtures with higher cement content exhibited higher penetration resistance. Control over the strength in the field is important because flowable fill backfill must gain sufficient strength to support wo rking loads, yet the ultimate strength must allow re-excavation of the material, if nece ssary. From the specimens acquired for this study, it has been found that the long-term st rength for flowable fill goes beyond what is defined and established as the strength to reach It was shown that flowable fill continues to gain long-term strength beyond the normal 28-day curing period. The ultimate strength will be different from the actual 28day strength. The hydrat ion of cement might continue for a long time beyond 28 days, and for mixes containing mineral admixtures, some mineral admixtures may participate in the pozzolanic reaction beyond 28 days. The strength results at 56 days on all mixes indi cated that the 56-day strength could be as much as 20%, or higher than the 28-day stre ngth. Thus, on average one should expect an increase of 10% to 20% in strength above that of 28-day strength. Statistical models were developed to pred ict the strength and volume change of a flowable fill mixture. The models take into account the factors which influence flowable fill strength and volume change. The factors used in the models is cement content,

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167 percent of mineral admixtures air content, and w/c ratio. The models are designed to estimate the LBR and compressive strength for 28and 56-day samples. The coefficient of determination (R2) for models estimating LBR strength for 28and 56-day samples are, respectively, 84.6% and 85.3%. The coefficient of determination (R2) for models estimating compressive strength for 28and 56-day samples are, respectively, 88.0% and 85.9%. The coefficient of determination valu e for percent volume change in models is 57.3%. Using the statistical performance of the prediction formulas, the percent volume change equation could not be recommended for design purposes due to its variation. The errors encountered during the models valida tion phase of the research were found to be unacceptable. Accelerating strength was explored as a means of testing and of estimating the long-term strength of flowable fill. In comp arison to prediction models developed in this study for estimating the strength of flowable fill, the acceler ating strength method is just an additional tool that one can use for re ducing the total time needed for strength prediction. A drying oven was used to accele rate the curing of flowable fill in this research study. The coefficient of determination (R2) for the accelerated mixes resulting from two days of oven curing of the 28-da y and 56-day samples, are 84.42% and 84.36%, respectively. The accelerated strengths of the 2-day oven-cured samples provided good correlation values to predict the 28-day stre ngth using the standard curing LBR results and the accelerated oven-dried curing results. 6.3 Recommendations The following recommendations are made for future flowable fill research: Validate the prediction equations with follow-up testing and field data.

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168 Introduce the design prediction equations to DOTs materials engineers (local, county and state), and concrete producers. Doing so will promote understanding of its usage and applications. Refine the related equations with field data.

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169 APPENDIX A FLOWABLE FILL STUDY BATCH MIX DESIGN MATRIX This appendix includes the design matrix (Table A-1), batc h mix combinations (Tables A-2 through A-9), typical computations of empirical mix design, and volumetric results per batch mix used for this res earch study (Tables A-10 through A-13).

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170 Table A-1. Full factorial design matrix Air Content (B) b1 b2 W/C Ratio (C) c1 c2 c3 c1 c2 c3 Mineral Admixtures (D) Cement Content (A) d1 d2 d3 d1 d2 d3 d1 d2 d3 d1 d2 d3 d1 d2 d3 d1 d2 d3 a1 a1b1c1d1 a1b1c1d1 a1b1c1d2 a1b1c1d2 a1b1c1d3 a1b1c1d3 a1b1c2d1 a1b1c2d1 a1b1c2d2 a1b1c2d2 a1b1c2d3 a1b1c2d3 a1b1c3d1 a1b1c3d1 a1b1c3d2 a1b1c3d2 a1b1c3d3 a1b1c3d3 a1b2c1d1 a1b2c1d1 a1b2c1d2 a1b2c1d2 a1b2c1d3 a1b2c1d3 a1b2c2d1 a1b2c2d1 a1b2c2d2 a1b2c2d2 a1b2c2d3 a1b2c2d3 a1b2c3d1 a1b2c3d1 a1b2c3d2 a1b2c3d2 a1b2c3d3 a1b2c3d3 a2 a2b1c1d1 a2b1c1d1 a2b1c1d2 a2b1c1d2 a2b1c1d3 a2b1c1d3 a2b1c2d1 a2b1c2d1 a2b1c2d2 a2b1c2d2 a2b1c2d3 a2b1c2d3 a2b1c3d1 a2b1c3d1 a2b1c3d2 a2b1c3d2 a2b1c3d3 a2b1c3d3 a2b2c1d1 a2b2c1d1 a2b2c1d2 a2b2c1d2 a2b2c1d3 a2b2c1d3 a2b2c2d1 a2b2c2d1 a2b2c2d2 a2b2c2d2 a2b2c2d3 a2b2c2d3 a2b2c3d1 a2b2c3d1 a2b2c3d2 a2b2c3d2 a2b2c3d3 a2b2c3d3 a3 a3b1c1d1 a3b1c1d1 a3b1c1d2 a3b1c1d2 a3b1c1d3 a3b1c1d3 a3b1c2d1 a3b1c2d1 a3b1c2d2 a3b1c2d2 a3b1c2d3 a3b1c2d3 a3b1c3d1 a3b1c3d1 a3b1c3d2 a3b1c3d2 a3b1c3d3 a3b1c3d3 a3b2c1d1 a3b2c1d1 a3b2c1d2 a3b2c1d2 a3b2c1d3 a3b2c1d3 a3b2c2d1 a3b2c2d1 a3b2c2d2 a3b2c2d2 a3b2c2d3 a3b2c2d3 a3b2c3d1 a3b2c3d1 a3b2c3d2 a3b2c3d2 a3b2c3d3 a3b2c3d3 a4 a4b1c1d1 a4b1c1d1 a4b1c1d2 a4b1c1d2 a4b1c1d3 a4b1c1d3 a4b1c2d1 a4b1c2d1 a4b1c2d2 a4b1c2d2 a4b1c2d3 a4b1c2d3 a4b1c3d1 a4b1c3d1 a4b1c3d2 a4b1c3d2 a4b1c3d3 a4b1c3d3 a4b2c1d1 a4b2c1d1 a4b2c1d2 a4b2c1d2 a4b2c1d3 a4b2c1d3 a4b2c2d1 a4b2c2d1 a4b2c2d2 a4b2c2d2 a4b2c2d3 a4b2c2d3 a4b2c3d1 a4b2c3d1 a4b2c3d2 a4b2c3d2 a4b2c3d3 a4b2c3d3 Note: shaded cells represent feasible mixture combinations

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171 Table A-2. Batch mix combinati ons 1 through 22 for Experiment 1 Random Batch Mixture Cement Air w/c Mineral Number Number Combination Content (lb/yd3) Content ratio Admixtures (%) 32 1 a1b1c1d1 50.0 7.5 2.5% 2.0 0 71 2 a2b1c1d1 100.0 7.5 2.5% 2.0 0 47 3 a3b1c1d1 150.0 7.5 2.5% 2.0 0 2 4 a4b1c1d1 200.0 7.5 2.5% 2.0 0 8 5 a1b1c1d2 50.0 7.5 2.5% 2.0 20 46 6 a2b1c1d2 100.0 7.5 2.5% 2.0 20 20 7 a3b1c1d2 150.0 7.5 2.5% 2.0 20 4 8 a4b1c1d2 200.0 7.5 2.5% 2.0 20 53 9 a1b1c1d3 50.0 7.5 2.5% 2.0 50 33 10 a2b1c1d3 100.0 7.5 2.5% 2.0 50 3 11 a3b1c1d3 150.0 7.5 2.5% 2.0 50 68 12 a4b1c1d3 200.0 7.5 2.5% 2.0 50 5 13 a1b1c2d1 50.0 7.5 2.5% 4.5 0 48 14 a2b1c2d1 100.0 7.5 2.5% 4.5 0 21 15 a3b1c2d1 150.0 7.5 2.5% 4.5 0 27 16 a4b1c2d1 200.0 7.5 2.5% 4.5 0 10 17 a1b1c2d2 50.0 7.5 2.5% 4.5 20 11 18 a2b1c2d2 100.0 7.5 2.5% 4.5 20 56 19 a3b1c2d2 150.0 7.5 2.5% 4.5 20 13 20 a4b1c2d2 200.0 7.5 2.5% 4.5 20 62 21 a1b1c2d3 50.0 7.5 2.5% 4.5 50 70 22 a2b1c2d3 100.0 7.5 2.5% 4.5 50

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172 Table A-3. Batch mix combinati ons 23 through 44 for Experiment 1 Random Batch Mixture Cement Air w/c Mineral Number Number Combination Content (lb/yd3) Content ratio Admixtures (%) 34 23 a3b1c2d3 150.0 7.5 2.5% 4.5 50 38 24 a4b1c2d3 200.0 7.5 2.5% 4.5 50 6 25 a1b1c3d1 50.0 7.5 2.5% 9.0 0 64 26 a2b1c3d1 100.0 7.5 2.5% 9.0 0 12 27 a3b1c3d1 150.0 7.5 2.5% 9.0 0 60 28 a4b1c3d1 200.0 7.5 2.5% 9.0 0 15 29 a1b1c3d2 50.0 7.5 2.5% 9.0 20 9 30 a2b1c3d2 100.0 7.5 2.5% 9.0 20 57 31 a3b1c3d2 150.0 7.5 2.5% 9.0 20 55 32 a4b1c3d2 200.0 7.5 2.5% 9.0 20 16 33 a1b1c3d3 50.0 7.5 2.5% 9.0 50 36 34 a2b1c3d3 100.0 7.5 2.5% 9.0 50 19 35 a3b1c3d3 150.0 7.5 2.5% 9.0 50 40 36 a4b1c3d3 200.0 7.5 2.5% 9.0 50 39 37 a1b2c1d1 50.0 17.5 2.5% 2.0 0 23 38 a2b2c1d1 100.0 17.5 2.5% 2.0 0 22 39 a3b2c1d1 150.0 17.5 2.5% 2.0 0 72 40 a4b2c1d1 200.0 17.5 2.5% 2.0 0 28 41 a1b2c1d2 50.0 17.5 2.5% 2.0 20 59 42 a2b2c1d2 100.0 17.5 2.5% 2.0 20 50 43 a3b2c1d2 150.0 17.5 2.5% 2.0 20 42 44 a4b2c1d2 200.0 17.5 2.5% 2.0 20

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173 Table A-4. Batch mix combinati ons 45 through 66 for Experiment 1 Random Batch Mixture Cement Air w/c Mineral Number Number Combination Content (lb/yd3) Content ratio Admixtures (%) 49 45 a1b2c1d3 50.0 17.5 2.5% 2.0 50 18 46 a2b2c1d3 100.0 17.5 2.5% 2.0 50 52 47 a3b2c1d3 150.0 17.5 2.5% 2.0 50 24 48 a4b2c1d3 200.0 17.5 2.5% 2.0 50 61 49 a1b2c2d1 50.0 17.5 2.5% 4.5 0 25 50 a2b2c2d1 100.0 17.5 2.5% 4.5 0 51 51 a3b2c2d1 150.0 17.5 2.5% 4.5 0 14 52 a4b2c2d1 200.0 17.5 2.5% 4.5 0 7 53 a1b2c2d2 50.0 17.5 2.5% 4.5 20 66 54 a2b2c2d2 100.0 17.5 2.5% 4.5 20 67 55 a3b2c2d2 150.0 17.5 2.5% 4.5 20 29 56 a4b2c2d2 200.0 17.5 2.5% 4.5 20 37 57 a1b2c2d3 50.0 17.5 2.5% 4.5 50 45 58 a2b2c2d3 100.0 17.5 2.5% 4.5 50 43 59 a3b2c2d3 150.0 17.5 2.5% 4.5 50 58 60 a4b2c2d3 200.0 17.5 2.5% 4.5 50 31 61 a1b2c3d1 50.0 17.5 2.5% 9.0 0 41 62 a2b2c3d1 100.0 17.5 2.5% 9.0 0 63 63 a3b2c3d1 150.0 17.5 2.5% 9.0 0 69 64 a4b2c3d1 200.0 17.5 2.5% 9.0 0 44 65 a1b2c3d2 50.0 17.5 2.5% 9.0 20 17 66 a2b2c3d2 100.0 17.5 2.5% 9.0 20

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174 Table A-5. Batch mix combinati ons 67 through 72 for Experiment 1 Random Batch Mixture Cement Air w/c Mineral Number Number Combination Content (lb/yd3) Content ratio Admixtures (%) 1 67 a3b2c3d2 150.0 17.5 2.5% 9.0 20 30 68 a4b2c3d2 200.0 17.5 2.5% 9.0 20 54 69 a1b2c3d3 50.0 17.5 2.5% 9.0 50 65 70 a2b2c3d3 100.0 17.5 2.5% 9.0 50 35 71 a3b2c3d3 150.0 17.5 2.5% 9.0 50 26 72 a4b2c3d3 200.0 17.5 2.5% 9.0 50

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175 Table A-6. Batch mix comb ination replicates 1r through 22r for Experiment 2 Random Batch Mixture Cement Air w/c Mineral Number Number Combination Content (lb/yd3) Content ratio Admixtures (%) 6 1r a1b1c1d1 50.0 7.5 2.5% 2.0 0 43 2r a2b1c1d1 100.0 7.5 2.5% 2.0 0 20 3r a3b1c1d1 150.0 7.5 2.5% 2.0 0 45 4r a4b1c1d1 200.0 7.5 2.5% 2.0 0 66 5r a1b1c1d2 50.0 7.5 2.5% 2.0 20 47 6r a2b1c1d2 100.0 7.5 2.5% 2.0 20 21 7r a3b1c1d2 150.0 7.5 2.5% 2.0 20 1 8r a4b1c1d2 200.0 7.5 2.5% 2.0 20 58 9r a1b1c1d3 50.0 7.5 2.5% 2.0 50 39 10r a2b1c1d3 100.0 7.5 2.5% 2.0 50 34 11r a3b1c1d3 150.0 7.5 2.5% 2.0 50 52 12r a4b1c1d3 200.0 7.5 2.5% 2.0 50 25 13r a1b1c2d1 50.0 7.5 2.5% 4.5 0 10 14r a2b1c2d1 100.0 7.5 2.5% 4.5 0 55 15r a3b1c2d1 150.0 7.5 2.5% 4.5 0 3 16r a4b1c2d1 200.0 7.5 2.5% 4.5 0 35 17r a1b1c2d2 50.0 7.5 2.5% 4.5 20 7 18r a2b1c2d2 100.0 7.5 2.5% 4.5 20 30 19r a3b1c2d2 150.0 7.5 2.5% 4.5 20 57 20r a4b1c2d2 200.0 7.5 2.5% 4.5 20 9 21r a1b1c2d3 50.0 7.5 2.5% 4.5 50 11 22r a2b1c2d3 100.0 7.5 2.5% 4.5 50

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176 Table A-7. Batch mix comb ination replicates 23r th rough 45r for Experiment 2 Random Batch Mixture Cement Air w/c Mineral Number Number Combination Content (lb/yd3) Content ratio Admixtures (%) 14 23r a3b1c2d3 150.0 7.5 2.5% 4.5 50 68 24r a4b1c2d3 200.0 7.5 2.5% 4.5 50 16 25r a1b1c3d1 50.0 7.5 2.5% 9.0 0 26 26r a2b1c3d1 100.0 7.5 2.5% 9.0 0 72 27r a3b1c3d1 150.0 7.5 2.5% 9.0 0 67 28r a4b1c3d1 200.0 7.5 2.5% 9.0 0 48 29r a1b1c3d2 50.0 7.5 2.5% 9.0 20 5 30r a2b1c3d2 100.0 7.5 2.5% 9.0 20 65 31r a3b1c3d2 150.0 7.5 2.5% 9.0 20 23 32r a4b1c3d2 200.0 7.5 2.5% 9.0 20 12 33r a1b1c3d3 50.0 7.5 2.5% 9.0 50 17 34r a2b1c3d3 100.0 7.5 2.5% 9.0 50 38 35r a3b1c3d3 150.0 7.5 2.5% 9.0 50 24 36r a4b1c3d3 200.0 7.5 2.5% 9.0 50 2 37r a1b2c1d1 50.0 17.5 2.5% 2.0 0 28 38r a2b2c1d1 100.0 17.5 2.5% 2.0 0 18 39r a3b2c1d1 150.0 17.5 2.5% 2.0 0 27 40r a4b2c1d1 200.0 17.5 2.5% 2.0 0 31 41r a1b2c1d2 50.0 17.5 2.5% 2.0 20 37 42r a2b2c1d2 100.0 17.5 2.5% 2.0 20 8 43r a3b2c1d2 150.0 17.5 2.5% 2.0 20 33 44r a4b2c1d2 200.0 17.5 2.5% 2.0 20 32 45r a1b2c1d3 50.0 17.5 2.5% 2.0 50

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177 Table A-8. Batch mix comb ination replicates 46r th rough 67r for Experiment 2 Random Batch Mixture Cement Air w/c Mineral Number Number Combination Content (lb/yd3) Content ratio Admixtures (%) 62 46r a2b2c1d3 100.0 17.5 2.5% 2.0 50 36 47r a3b2c1d3 150.0 17.5 2.5% 2.0 50 40 48r a4b2c1d3 200.0 17.5 2.5% 2.0 50 46 49r a1b2c2d1 50.0 17.5 2.5% 4.5 0 69 50r a2b2c2d1 100.0 17.5 2.5% 4.5 0 64 51r a3b2c2d1 150.0 17.5 2.5% 4.5 0 41 52r a4b2c2d1 200.0 17.5 2.5% 4.5 0 49 53r a1b2c2d2 50.0 17.5 2.5% 4.5 20 44 54r a2b2c2d2 100.0 17.5 2.5% 4.5 20 42 55r a3b2c2d2 150.0 17.5 2.5% 4.5 20 22 56r a4b2c2d2 200.0 17.5 2.5% 4.5 20 13 57r a1b2c2d3 50.0 17.5 2.5% 4.5 50 50 58r a2b2c2d3 100.0 17.5 2.5% 4.5 50 63 59r a3b2c2d3 150.0 17.5 2.5% 4.5 50 56 60r a4b2c2d3 200.0 17.5 2.5% 4.5 50 60 61r a1b2c3d1 50.0 17.5 2.5% 9.0 0 29 62r a2b2c3d1 100.0 17.5 2.5% 9.0 0 15 63r a3b2c3d1 150.0 17.5 2.5% 9.0 0 54 64r a4b2c3d1 200.0 17.5 2.5% 9.0 0 59 65r a1b2c3d2 50.0 17.5 2.5% 9.0 20 70 66r a2b2c3d2 100.0 17.5 2.5% 9.0 20 53 67r a3b2c3d2 150.0 17.5 2.5% 9.0 20

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178 Table A-9. Batch mix comb ination replicates 68r th rough 72r for Experiment 2 Random Batch Mixture Cement Air w/c Mineral Number Number Combination Content (lb/yd3) Content ratio Admixtures (%) 61 68r a4b2c3d2 200.0 17.5 2.5% 9.0 20 19 69r a1b2c3d3 50.0 17.5 2.5% 9.0 50 71 70r a2b2c3d3 100.0 17.5 2.5% 9.0 50 4 71r a3b2c3d3 150.0 17.5 2.5% 9.0 50 51 72r a4b2c3d3 200.0 17.5 2.5% 9.0 50 Typical computations fo r mixing flowable fill In this computation, one empirical flowab le fill mixture will be design using the volumetric method discussed in chapter 3. The following outlined the steps used for designing 1 cubic yard (yd3) mixture: Determine the amount of materials require d for mixtures with the following design criteria: Batch Mix #23 cementitious content = 150 lb/yd3 w/c = 4.50 air content = 7.5 2.5% mineral admixtures = 50% slag The following are known properties for the materi als that will be us ed to create the mixtures: Sc = 3.15 specific gravity of cement Ss = 2.42 specific gravity of slag Sf = 2.36 specific gravity of fly ash Sag = 2.63 specific gravity of fine aggregate N = 3.00 percent of natural moisture content for fine aggregate L = 0.40 percent absorption for fine aggregate Solution for batch mix #23 1. Calculate weight of cement, lbs. per cubic yard (cu. yd.) 00 75 50 0 150 p wS content us cementitio C

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179 2. Calculate weight of slag, lbs. per cu. yd 00 75 00 75 150 w wC content us cementitio S 3. Calculate weight of water, lbs. per cu. yard (cu. yd.) 00 675 00 75 00 75 50 4 / w w wS C ratio c w W 4. Calculate absolute volume of cement, cu. ft. per cu. yd. 3382 0 4 62 15 3 00 75 4 62 ft S C Cc w v 5. Calculate absolute volume of slag, cu. ft. per cu. yd. 3497 0 4 62 42 2 00 75 4 62 ft S S Ss w v 6. Calculate absolute volume of water, cu. ft. per cu. yd. 3817 10 4 62 00 675 4 62 ft W Ww v 7. Calculate absolute volume of targ et air content, cu. ft. per cu. yd. 3025 2 100 27 5 7 100 27ft A Ap v 8. Calculate total absolute volume of know ingredients 3721 13ft A W S Cv v v v 9. Calculate absolute volume of satu rated-surface-dry (SSD) fine aggregates, cu. ft. per cu. yd. 3279 13 ) ( 27ft A W S C FAv v v v vs

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180 10. Calculate weight of saturated-surfac e-dry fine aggregates, lbs. per cu. yd. 24 2179 4 62 63 2 279 13 4 62 ag vs wsS FA FA 11. Calculate the sand to water (s/w ) ratio (s/w ratio range: 1.73 7.20 ) 229 3 00 675 24 2179 w wsW FA W S 12. Calculate weight of fine aggregate base on natural mo isture content, lbs. per cu. yd. 67 2235 004 0 1 03 0 1 24 2179 1 1 L N FA FAws wn 13. Correct the weight of water content due to percentage of moisture difference, lbs. per cu. yd. 43 731 43 56 00 675 43 56 24 2179 67 2235 W W W W FA FA Ww wn ws A summary of materials required for mixtur es is provided in Tables A-10 through A-13.

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181 Table A-10. Volume computation re sults for batch mixes 1 through 36 Volume of Batch = 1.0 yd3Volume of Batch = 5.50 ft3RandomBatch Weight of Weight of Weight of Weight of Weight of Weight of Weight of Weight of Weight of Weight of sand/water NumberNumberCement (lbs)Slag (lbs)Fly Ash (lbs)Water (lbs)Fine Aggregate (lbs)Cement (lbs)Slag (lbs)Fly Ash (lbs)Water (lbs)Fin e Aggregate (lbs)ratio 32150.000.000.00100.00 lbs3793.95 lbs10.190.000.0020.37 lbs772.84 lbs37.94 712100.000.000.00200.00 lbs3489.21 lbs20.370.000.0040.74 lbs710.76 lbs17.45 473150.000.000.00300.00 lbs3184.46 lbs30.560.000.0061.11 lbs648.69 lbs10.61 24200.000.000.00400.00 lbs2879.71 lbs40.740.000.0081.48 lbs586.61 lbs 7.20 8540.000.0010.00100.00 lbs3791.16 lbs8.150.002.0420.37 lbs772.27 lbs37.91 46680.000.0020.00200.00 lbs3483.62 lbs16.300.004.0740.74 lbs709.63 lbs17.42 207120.000.0030.00300.00 lbs3176.07 lbs24.440.006.1161.11 lbs646.98 lbs10.59 48160.000.0040.00400.00 lbs2868.53 lbs32.590.008.1581.48 lbs584.33 lbs 7.17 53925.0025.000.00100.00 lbs3792.31 lbs5.095.090.0020.37 lbs772.51 lbs37.92 331050.0050.000.00200.00 lbs3485.92 lbs10.1910.190.0040.74 lbs710.09 lbs17.43 31175.0075.000.00300.00 lbs3179.53 lbs15.2815.280.0061.11 lbs647.68 lbs10.60 6812100.00100.000.00400.00 lbs2873.14 lbs20.3720.370.0081.48 lbs585.27 lbs 7.18 51350.000.000.00225.00 lbs3465.20 lbs10.190.000.0045.83 lbs705.87 lbs15.40 4814100.000.000.00450.00 lbs2831.71 lbs20.370.000.0091.67 lbs576.83 lbs 6.29 2115150.000.000.00675.00 lbs2198.21 lbs30.560.000.00137.50 lbs447.78 lbs 3.26 2716200.000.000.00900.00 lbs1564.71 lbs40.740.000.00183.33 lbs318.74 lbs 1.74 101740.000.0010.00225.00 lbs3462.41 lbs8.150.002.0445.83 lbs705.30 lbs15.39 111880.000.0020.00450.00 lbs2826.12 lbs16.300.004.0791.67 lbs575.69 lbs 6.28 5619120.000.0030.00675.00 lbs2189.82 lbs24.440.006.11137.50 lbs446.08 lbs 3.24 1320160.000.0040.00900.00 lbs1553.53 lbs32.590.008.15183.33 lbs316.46 lbs 1.73 622125.0025.000.00225.00 lbs3463.56 lbs5.095.090.0045.83 lbs705.54 lbs15.39 702250.0050.000.00450.00 lbs2828.42 lbs10.1910.190.0091.67 lbs576.16 lbs 6.29 342375.0075.000.00675.00 lbs2193.28 lbs15.2815.280.00137.50 lbs446.78 lbs 3.25 3824100.00100.000.00900.00 lbs1558.14 lbs20.3720.370.00183.33 lbs317.40 lbs 1.73 62550.000.000.00450.00 lbs2873.45 lbs10.190.000.0091.67 lbs585.33 lbs 6.39 6426100.000.000.00900.00 lbs1648.21 lbs20.370.000.00183.33 lbs335.75 lbs 1.83 1227150.000.000.001350.00 lbs422.96 lbs30.560.000.00275.00 lbs86.16 lbs0.31 6028200.000.000.001800.00 lbs-802.29 lbs40.740.000.00366.67 lbs-163.43 lbs-0.45 152940.000.0010.00450.00 lbs2870.66 lbs8.150.002.0491.67 lbs584.76 lbs6.38 93080.000.0020.00900.00 lbs1642.62 lbs16.300.004.07183.33 lbs334.61 lbs 1.83 5731120.000.0030.001350.00 lbs414.57 lbs24.440.006.11275.00 lbs84.45 lbs0.31 5532160.000.0040.001800.00 lbs-813.47 lbs32.590.008.15366.67 lbs-165.71 lbs-0.45 163325.0025.000.00450.00 lbs2871.81 lbs5.095.090.0091.67 lbs585.00 lbs 6.38 363450.0050.000.00900.00 lbs1644.92 lbs10.1910.190.00183.33 lbs335.08 lbs 1.83 193575.0075.000.001350.00 lbs418.03 lbs15.2815.280.00275.00 lbs85.15 lbs0.31 4036100.00100.000.001800.00 lbs-808.86 lbs20.3720.370.00366.67 lbs-164.77 lbs-0.45

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182 Table A-11. Volume computation re sults for batch mixes 37 through 72 Volume of Batch = 1.0 yd3Volume of Batch = 5.50 ft3RandomBatch Weight of Weight of Weight of Weight of Weight of Weight of Weight of Weight of Weight of Weight of sand/water NumberNumberCement (lbs)Slag (lbs)Fly Ash (lbs)Water (lbs)Fine Aggregate (lbs)Cement (lbs)Slag (lbs)Fly Ash (lbs)Water (lbs)Fin e Aggregate (lbs)ratio 393750.000.000.00100.00 lbs3350.85 lbs10.190.000.0020.37 lbs682.58 lbs33.51 2338100.000.000.00200.00 lbs3046.10 lbs20.370.000.0040.74 lbs620.50 lbs15.23 2239150.000.000.00300.00 lbs2741.36 lbs30.560.000.0061.11 lbs558.42 lbs9.14 7240200.000.000.00400.00 lbs2436.61 lbs40.740.000.0081.48 lbs496.35 lbs 6.09 284140.000.0010.00100.00 lbs3348.05 lbs8.150.002.0420.37 lbs682.01 lbs33.48 594280.000.0020.00200.00 lbs3040.51 lbs16.300.004.0740.74 lbs619.36 lbs15.20 5043120.000.0030.00300.00 lbs2732.97 lbs24.440.006.1161.11 lbs556.72 lbs9.11 4244160.000.0040.00400.00 lbs2425.43 lbs32.590.008.1581.48 lbs494.07 lbs 6.06 494525.0025.000.00100.00 lbs3349.20 lbs5.095.090.0020.37 lbs682.25 lbs33.49 184650.0050.000.00200.00 lbs3042.81 lbs10.1910.190.0040.74 lbs619.83 lbs15.21 524775.0075.000.00300.00 lbs2736.42 lbs15.2815.280.0061.11 lbs557.42 lbs9.12 2448100.00100.000.00400.00 lbs2430.03 lbs20.3720.370.0081.48 lbs495.01 lbs 6.08 614950.000.000.00225.00 lbs3022.10 lbs10.190.000.0045.83 lbs615.61 lbs13.43 2550100.000.000.00450.00 lbs2388.60 lbs20.370.000.0091.67 lbs486.57 lbs 5.31 5151150.000.000.00675.00 lbs1755.11 lbs30.560.000.00137.50 lbs357.52 lbs 2.60 1452200.000.000.00900.00 lbs1121.61 lbs40.740.000.00183.33 lbs228.48 lbs 1.25 75340.000.0010.00225.00 lbs3019.30 lbs8.150.002.0445.83 lbs615.04 lbs13.42 665480.000.0020.00450.00 lbs2383.01 lbs16.300.004.0791.67 lbs485.43 lbs 5.30 6755120.000.0030.00675.00 lbs1746.72 lbs24.440.006.11137.50 lbs355.81 lbs 2.59 2956160.000.0040.00900.00 lbs1110.43 lbs32.590.008.15183.33 lbs226.20 lbs 1.23 375725.0025.000.00225.00 lbs3020.45 lbs5.095.090.0045.83 lbs615.28 lbs13.42 455850.0050.000.00450.00 lbs2385.31 lbs10.1910.190.0091.67 lbs485.90 lbs 5.30 435975.0075.000.00675.00 lbs1750.17 lbs15.2815.280.00137.50 lbs356.52 lbs 2.59 5860100.00100.000.00900.00 lbs1115.03 lbs20.3720.370.00183.33 lbs227.14 lbs 1.24 316150.000.000.00450.00 lbs2430.35 lbs10.190.000.0091.67 lbs495.07 lbs 5.40 4162100.000.000.00900.00 lbs1205.10 lbs20.370.000.00183.33 lbs245.48 lbs 1.34 6363150.000.000.001350.00 lbs-20.14 lbs30.560.000.00275.00 lbs-4.10 lbs-0.01 6964200.000.000.001800.00 lbs-1245.39 lbs40.740.000.00366.67 lbs-253.69 lbs-0.69 446540.000.0010.00450.00 lbs2427.55 lbs8.150.002.0491.67 lbs494.50 lbs5.39 176680.000.0020.00900.00 lbs1199.51 lbs16.300.004.07183.33 lbs244.35 lbs 1.33 167120.000.0030.001350.00 lbs-28.53 lbs24.440.006.11275.00 lbs-5.81 lbs-0.02 3068160.000.0040.001800.00 lbs-1256.57 lbs32.590.008.15366.67 lbs-255.97 lbs-0.70 546925.0025.000.00450.00 lbs2428.70 lbs5.095.090.0091.67 lbs494.74 lbs 5.40 657050.0050.000.00900.00 lbs1201.81 lbs10.1910.190.00183.33 lbs244.81 lbs 1.34 357175.0075.000.001350.00 lbs-25.08 lbs15.2815.280.00275.00 lbs-5.11 lbs-0.02 2672100.00100.000.001800.00 lbs-1251.97 lbs20.3720.370.00366.67 lbs-255.03 lbs-0.70

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183 Table A-12. Volume computation results fo r replicate batch mixes 1r through 36r Volume of Batch = 1.0 yd3Volume of Batch = 5.50 ft3RandomBatch Weight of Weight of Weight of Weight of Weight of Weight of Weight of Weight of Weight of Weight of sand/water NumberNumberCement (lbs)Slag (lbs)Fly Ash (lbs)Water (lbs)Fine Aggregate (lbs)Cement (lbs)Slag (lbs)Fly Ash (lbs)Water (lbs)Fin e Aggregate (lbs)ratio 61r50.000.000.00100.00 lbs3793.95 lbs10.190.000.0020.37 lbs772.84 lbs37.94 432r100.000.000.00200.00 lbs3489.21 lbs20.370.000.0040.74 lbs710.76 lbs17.45 203r150.000.000.00300.00 lbs3184.46 lbs30.560.000.0061.11 lbs648.69 lbs10.61 454r200.000.000.00400.00 lbs2879.71 lbs40.740.000.0081.48 lbs586.61 lbs 7.20 665r40.000.0010.00100.00 lbs3791.16 lbs8.150.002.0420.37 lbs772.27 lbs37.91 476r80.000.0020.00200.00 lbs3483.62 lbs16.300.004.0740.74 lbs709.63 lbs17.42 217r120.000.0030.00300.00 lbs3176.07 lbs24.440.006.1161.11 lbs646.98 lbs10.59 18r160.000.0040.00400.00 lbs2868.53 lbs32.590.008.1581.48 lbs584.33 lbs 7.17 589r25.0025.000.00100.00 lbs3792.31 lbs5.095.090.0020.37 lbs772.51 lbs37.92 3910r50.0050.000.00200.00 lbs3485.92 lbs10.1910.190.0040.74 lbs710.09 lbs17.43 3411r75.0075.000.00300.00 lbs3179.53 lbs15.2815.280.0061.11 lbs647.68 lbs10.60 5212r100.00100.000.00400.00 lbs2873.14 lbs20.3720.370.0081.48 lbs585.27 lbs 7.18 2513r50.000.000.00225.00 lbs3465.20 lbs10.190.000.0045.83 lbs705.87 lbs15.40 1014r100.000.000.00450.00 lbs2831.71 lbs20.370.000.0091.67 lbs576.83 lbs 6.29 5515r150.000.000.00675.00 lbs2198.21 lbs30.560.000.00137.50 lbs447.78 lbs 3.26 316r200.000.000.00900.00 lbs1564.71 lbs40.740.000.00183.33 lbs318.74 lbs 1.74 3517r40.000.0010.00225.00 lbs3462.41 lbs8.150.002.0445.83 lbs705.30 lbs15.39 718r80.000.0020.00450.00 lbs2826.12 lbs16.300.004.0791.67 lbs575.69 lbs 6.28 3019r120.000.0030.00675.00 lbs2189.82 lbs24.440.006.11137.50 lbs446.08 lbs 3.24 5720r160.000.0040.00900.00 lbs1553.53 lbs32.590.008.15183.33 lbs316.46 lbs 1.73 921r25.0025.000.00225.00 lbs3463.56 lbs5.095.090.0045.83 lbs705.54 lbs15.39 1122r50.0050.000.00450.00 lbs2828.42 lbs10.1910.190.0091.67 lbs576.16 lbs 6.29 1423r75.0075.000.00675.00 lbs2193.28 lbs15.2815.280.00137.50 lbs446.78 lbs 3.25 6824r100.00100.000.00900.00 lbs1558.14 lbs20.3720.370.00183.33 lbs317.40 lbs 1.73 1625r50.000.000.00450.00 lbs2873.45 lbs10.190.000.0091.67 lbs585.33 lbs 6.39 2626r100.000.000.00900.00 lbs1648.21 lbs20.370.000.00183.33 lbs335.75 lbs 1.83 7227r150.000.000.001350.00 lbs422.96 lbs30.560.000.00275.00 lbs86.16 lbs0.31 6728r200.000.000.001800.00 lbs-802.29 lbs40.740.000.00366.67 lbs-163.43 lbs-0.45 4829r40.000.0010.00450.00 lbs2870.66 lbs8.150.002.0491.67 lbs584.76 lbs6.38 530r80.000.0020.00900.00 lbs1642.62 lbs16.300.004.07183.33 lbs334.61 lbs 1.83 6531r120.000.0030.001350.00 lbs414.57 lbs24.440.006.11275.00 lbs84.45 lbs0.31 2332r160.000.0040.001800.00 lbs-813.47 lbs32.590.008.15366.67 lbs-165.71 lbs-0.45 1233r25.0025.000.00450.00 lbs2871.81 lbs5.095.090.0091.67 lbs585.00 lbs 6.38 1734r50.0050.000.00900.00 lbs1644.92 lbs10.1910.190.00183.33 lbs335.08 lbs 1.83 3835r75.0075.000.001350.00 lbs418.03 lbs15.2815.280.00275.00 lbs85.15 lbs0.31 2436r100.00100.000.001800.00 lbs-808.86 lbs20.3720.370.00366.67 lbs-164.77 lbs-0.45

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184 Table A-13. Volume computation resu lts for batch mixes 37r through 72r Volume of Batch = 1.0 yd3Volume of Batch = 5.50 ft3RandomBatch Weight of Weight of Weight of Weight of Weight of Weight of Weight of Weight of Weight of Weight of sand/water NumberNumberCement (lbs)Slag (lbs)Fly Ash (lbs)Water (lbs)Fine Aggregate (lbs)Cement (lbs)Slag (lbs)Fly Ash (lbs)Water (lbs)Fin e Aggregate (lbs)ratio 237r50.000.000.00100.00 lbs3350.85 lbs10.190.000.0020.37 lbs682.58 lbs33.51 2838r100.000.000.00200.00 lbs3046.10 lbs20.370.000.0040.74 lbs620.50 lbs15.23 1839r150.000.000.00300.00 lbs2741.36 lbs30.560.000.0061.11 lbs558.42 lbs9.14 2740r200.000.000.00400.00 lbs2436.61 lbs40.740.000.0081.48 lbs496.35 lbs 6.09 3141r40.000.0010.00100.00 lbs3348.05 lbs8.150.002.0420.37 lbs682.01 lbs33.48 3742r80.000.0020.00200.00 lbs3040.51 lbs16.300.004.0740.74 lbs619.36 lbs15.20 843r120.000.0030.00300.00 lbs2732.97 lbs24.440.006.1161.11 lbs556.72 lbs9.11 3344r160.000.0040.00400.00 lbs2425.43 lbs32.590.008.1581.48 lbs494.07 lbs 6.06 3245r25.0025.000.00100.00 lbs3349.20 lbs5.095.090.0020.37 lbs682.25 lbs33.49 6246r50.0050.000.00200.00 lbs3042.81 lbs10.1910.190.0040.74 lbs619.83 lbs15.21 3647r75.0075.000.00300.00 lbs2736.42 lbs15.2815.280.0061.11 lbs557.42 lbs9.12 4048r100.00100.000.00400.00 lbs2430.03 lbs20.3720.370.0081.48 lbs495.01 lbs 6.08 4649r50.000.000.00225.00 lbs3022.10 lbs10.190.000.0045.83 lbs615.61 lbs13.43 6950r100.000.000.00450.00 lbs2388.60 lbs20.370.000.0091.67 lbs486.57 lbs 5.31 6451r150.000.000.00675.00 lbs1755.11 lbs30.560.000.00137.50 lbs357.52 lbs 2.60 4152r200.000.000.00900.00 lbs1121.61 lbs40.740.000.00183.33 lbs228.48 lbs 1.25 4953r40.000.0010.00225.00 lbs3019.30 lbs8.150.002.0445.83 lbs615.04 lbs13.42 4454r80.000.0020.00450.00 lbs2383.01 lbs16.300.004.0791.67 lbs485.43 lbs 5.30 4255r120.000.0030.00675.00 lbs1746.72 lbs24.440.006.11137.50 lbs355.81 lbs 2.59 2256r160.000.0040.00900.00 lbs1110.43 lbs32.590.008.15183.33 lbs226.20 lbs 1.23 1357r25.0025.000.00225.00 lbs3020.45 lbs5.095.090.0045.83 lbs615.28 lbs13.42 5058r50.0050.000.00450.00 lbs2385.31 lbs10.1910.190.0091.67 lbs485.90 lbs 5.30 6359r75.0075.000.00675.00 lbs1750.17 lbs15.2815.280.00137.50 lbs356.52 lbs 2.59 5660r100.00100.000.00900.00 lbs1115.03 lbs20.3720.370.00183.33 lbs227.14 lbs 1.24 6061r50.000.000.00450.00 lbs2430.35 lbs10.190.000.0091.67 lbs495.07 lbs 5.40 2962r100.000.000.00900.00 lbs1205.10 lbs20.370.000.00183.33 lbs245.48 lbs 1.34 1563r150.000.000.001350.00 lbs-20.14 lbs30.560.000.00275.00 lbs-4.10 lbs-0.01 5464r200.000.000.001800.00 lbs-1245.39 lbs40.740.000.00366.67 lbs-253.69 lbs-0.69 5965r40.000.0010.00450.00 lbs2427.55 lbs8.150.002.0491.67 lbs494.50 lbs5.39 7066r80.000.0020.00900.00 lbs1199.51 lbs16.300.004.07183.33 lbs244.35 lbs 1.33 5367r120.000.0030.001350.00 lbs-28.53 lbs24.440.006.11275.00 lbs-5.81 lbs-0.02 6168r160.000.0040.001800.00 lbs-1256.57 lbs32.590.008.15366.67 lbs-255.97 lbs-0.70 1969r25.0025.000.00450.00 lbs2428.70 lbs5.095.090.0091.67 lbs494.74 lbs 5.40 7170r50.0050.000.00900.00 lbs1201.81 lbs10.1910.190.00183.33 lbs244.81 lbs 1.34 471r75.0075.000.001350.00 lbs-25.08 lbs15.2815.280.00275.00 lbs-5.11 lbs-0.02 5172r100.00100.000.001800.00 lbs-1251.97 lbs20.3720.370.00366.67 lbs-255.03 lbs-0.70

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185 APPENDIX B LBR AND COMPRESSIVE STRENGTH DATA OBTAINED IN THE LABORATORY This appendix includes plot for the bear ing strength in LBR and the compressive strength (stress) versus time for all laborat ory mixes. Proctor penetrometer resistance showing the setting behavior for all batch mixt ures are provided in the tables. In addition, tables are provided showing the individual LBR reading for the 2-days oven samples.

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186 BEARING STRENGTH (LBR) vs TIME FLOWABLE FILL 2005 ( BATCH MIX 4 )0 50 100 150 200 250 0204060 TIME(DAYS)STRENGTH(LBR) BM 4 BM 4a BM 4r BEARING STRENGTH (LBR) vs TIME FLOWABLE FILL 2005 ( BATCH MIX 8 )0 50 100 150 200 250 0204060 TIME(DAYS)STRENGTH(LBR) BM 8 BM 8r BEARING STRENGTH (LBR) vs TIME FLOWABLE FILL 2005 ( BATCH MIX 12 )0 50 100 150 200 250 0204060 TIME(DAYS)STRENGTH(LBR) BM 12 BM 12r BEARING STRENGTH (LBR) vs TIME FLOWABLE FILL 2005 ( BATCH MIX 14 )0 50 100 150 200 250 0204060 TIME(DAYS)STRENGTH(LBR) BM 14 BM 14r UnConfined Compressive Stress vs TIME FLOWABLE FILL 2005 ( BATCH MIX 4 )0.00 50.00 100.00 150.00 200.00 250.00 0204060 TIME(DAYS)STRESS(PSI) BM 4 BM 4a BM 4r UnConfined Compressive Stress vs TIME FLOWABLE FILL 2005 ( BATCH MIX 12 )0.00 50.00 100.00 150.00 200.00 250.00 0204060 TIME(DAYS)STRESS(PSI) BM 12 BM 12r UnConfined Compressive Stress vs TIME FLOWABLE FILL 2005 ( BATCH MIX 8 )0.00 50.00 100.00 150.00 200.00 250.00 0204060 TIME(DAYS)STRESS(PSI) BM 8 BM 8r UnConfined Compressive Stress vs TIME FLOWABLE FILL 2005 ( BATCH MIX 14 )0.00 50.00 100.00 150.00 200.00 250.00 0204060 TIME(DAYS)STRESS(PSI) BM 14 BM 14r Figure B-1. Batch mix 4 through batch mi x 14 bearing strength, and compressive strength versus time

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187 BEARING STRENGTH (LBR) vs TIME FLOWABLE FILL 2005 ( BATCH MIX15 )0 50 100 150 200 250 0204060 TIME(DAYS)STRENGTH(LBR) BM 15 BM 15Type I BM 15r BEARING STRENGTH (LBR) vs TIME FLOWABLE FILL 2005 ( BATCH MIX 16 )0 50 100 150 200 250 300 350 0204060 TIME(DAYS)STRENGTH(LBR) BM 16 BM 16a BM 16r BEARING STRENGTH (LBR) vs TIME FLOWABLE FILL 2005 ( BATCH MIX 18 )0 50 100 150 200 250 0204060 TIME(DAYS)STRENGTH(LBR) BM 18 BM 18r BEARING STRENGTH (LBR) vs TIME FLOWABLE FILL 2005 ( BATCH MIX 19 )0 50 100 150 200 250 0204060 TIME(DAYS)STRENGTH(LBR) BM 19 BM 19r UnConfined Compressive Stress vs TIME FLOWABLE FILL 2005 ( BATCH MIX15 )0.00 50.00 100.00 150.00 200.00 250.00 0204060 TIME(DAYS)STRESS(PSI) BM 15 BM 15Type I BM 15r UnConfined Compressive Stress vs TIME FLOWABLE FILL 2005 ( BATCH MIX 18 )0.00 50.00 100.00 150.00 200.00 250.00 0204060 TIME(DAYS)STRESS(PSI) BM 18 BM 18r UnConfined Compressive Stress vs TIME FLOWABLE FILL 2005 ( BATCH MIX 16 )0.00 50.00 100.00 150.00 200.00 250.00 0204060 TIME(DAYS)STRESS(PSI) BM 16 BM 16a BM 16r UnConfined Compressive Stress vs TIME FLOWABLE FILL 2005 ( BATCH MIX 19 )0.00 50.00 100.00 150.00 200.00 250.00 0204060 TIME(DAYS)STRESS(PSI) BM 19 BM 19r Figure B-2. Batch mix 15 through batch mi x 19 bearing strength, and compressive strength versus time

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188 BEARING STRENGTH (LBR) vs TIME FLOWABLE FILL 2005 ( BATCH MIX 20 )0 50 100 150 200 250 0204060 TIME(DAYS)STRENGTH(LBR) BM 20 BM 20r BEARING STRENGTH (LBR) vs TIME FLOWABLE FILL 2005 ( BATCH MIX 22 )0 50 100 150 200 250 0204060 TIME(DAYS)STRENGTH(LBR) BM 22 BM 22r BEARING STRENGTH (LBR) vs TIME FLOWABLE FILL 2005 ( BATCH MIX 23 )0 50 100 150 200 250 0204060 TIME(DAYS)STRENGTH(LBR) BM 23 BM 23r BEARING STRENGTH (LBR) vs TIME FLOWABLE FILL 2005 ( BATCH MIX 24 )0 50 100 150 200 250 300 0204060 TIME(DAYS)STRENGTH(LBR) BM 24 BM 24r UnConfined Compressive Stress vs TIME FLOWABLE FILL 2005 ( BATCH MIX 20 )0.00 50.00 100.00 150.00 200.00 250.00 0204060 TIME(DAYS)STRESS(PSI) BM 20 BM 20r UnConfined Compressive Stress vs TIME FLOWABLE FILL 2005 ( BATCH MIX 23 )0.00 50.00 100.00 150.00 200.00 250.00 0204060 TIME(DAYS)STRESS(PSI) BM 23 BM 23r UnConfined Compressive Stress vs TIME FLOWABLE FILL 2005 ( BATCH MIX 22 )0.00 50.00 100.00 150.00 200.00 250.00 0204060 TIME(DAYS)STRESS(PSI) BM 22 BM 22r UnConfined Compressive Stress vs TIME FLOWABLE FILL 2005 ( BATCH MIX 24 )0.00 50.00 100.00 150.00 200.00 250.00 0204060 TIME(DAYS)STRESS(PSI) BM 24 BM 24r Figure B-3. Batch mix 20 through batch mi x 24 bearing strength, and compressive strength versus time

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189 BEARING STRENGTH (LBR) vs TIME FLOWABLE FILL 2005 ( BATCH MIX 25 )0 50 100 150 200 250 0204060 TIME(DAYS)STRENGTH(LBR) BM 25 BM 25Type I BM 25r BM 25rb BEARING STRENGTH (LBR) vs TIME FLOWABLE FILL 2005 ( BATCH MIX 26 )0 50 100 150 200 250 0204060 TIME(DAYS)STRENGTH(LBR) BM 26 BM 26r BEARING STRENGTH (LBR) vs TIME FLOWABLE FILL 2005 ( BATCH MIX 30 )0 50 100 150 200 250 0204060 TIME(DAYS)STRENGTH(LBR) BM 30 BM 30r BEARING STRENGTH (LBR) vs TIME FLOWABLE FILL 2005 ( BATCH MIX 33 )0 50 100 150 200 250 0204060 TIME(DAYS)STRENGTH(LBR) BM 33 BM 33r UnConfined Compressive Stress vs TIME FLOWABLE FILL 2005 ( BATCH MIX 25 )0.00 50.00 100.00 150.00 200.00 250.00 0204060 TIME(DAYS)STRESS(PSI) BM 25 BM 25Type I BM 25r BM 25rb UnConfined Compressive Stress vs TIME FLOWABLE FILL 2005 ( BATCH MIX 30 )0.00 50.00 100.00 150.00 200.00 250.00 0204060 TIME(DAYS)STRESS(PSI) BM 30 BM 30r UnConfined Compressive Stress vs TIME FLOWABLE FILL 2005 ( BATCH MIX 26 )0.00 50.00 100.00 150.00 200.00 250.00 0204060 TIME(DAYS)STRESS(PSI) BM 26 BM 26r UnConfined Compressive Stress vs TIME FLOWABLE FILL 2005 ( BATCH MIX 33 )0.00 50.00 100.00 150.00 200.00 250.00 0204060 TIME(DAYS)STRESS(PSI) BM 33 BM 33r Figure B-4. Batch mix 25 through batch mi x 33 bearing strength, and compressive strength versus time

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190 BEARING STRENGTH (LBR) vs TIME FLOWABLE FILL 2005 ( BATCH MIX 34 )0 50 100 150 200 250 0204060 TIME(DAYS)STRENGTH(LBR) BM 34 BM 34r BEARING STRENGTH (LBR) vs TIME FLOWABLE FILL 2005 ( BATCH MIX 40 )0 50 100 150 200 250 0204060 TIME(DAYS)STRENGTH(LBR) BM 40 BM 40r BEARING STRENGTH (LBR) vs TIME FLOWABLE FILL 2005 ( BATCH MIX 44 )0 50 100 150 200 250 0204060 TIME(DAYS)STRENGTH(LBR) BM 44 BM 44r BEARING STRENGTH (LBR) vs TIME FLOWABLE FILL 2005 ( BATCH MIX 48 )0 50 100 150 200 250 300 0204060 TIME(DAYS)STRENGTH(LBR) BM 48 BM 48Type I BM 48r BM 48rb UnConfined Compressive Stress vs TIME FLOWABLE FILL 2005 ( BATCH MIX 34 )0.00 50.00 100.00 150.00 200.00 250.00 0204060 TIME(DAYS)STRESS(PSI) BM 34 BM 34r UnConfined Compressive Stress vs TIME FLOWABLE FILL 2005 ( BATCH MIX 44 )0.00 50.00 100.00 150.00 200.00 250.00 0204060 TIME(DAYS)STRESS(PSI) BM 44 BM 44r UnConfined Compressive Stress vs TIME FLOWABLE FILL 2005 ( BATCH MIX 40 )0.00 50.00 100.00 150.00 200.00 250.00 0204060 TIME(DAYS)STRESS(PSI) BM 40 BM 40r UnConfined Compressive Stress vs TIME FLOWABLE FILL 2005 ( BATCH MIX 48 )0.00 50.00 100.00 150.00 200.00 250.00 0204060 TIME(DAYS)STRESS(PSI) BM 48 BM 48Type I BM 48r BM 48rb Figure B-5. Batch mix 34 through batch mi x 48 bearing strength, and compressive strength versus time

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191 BEARING STRENGTH (LBR) vs TIME FLOWABLE FILL 2005 ( BATCH MIX 50 )0 50 100 150 200 250 0204060 TIME(DAYS)STRENGTH(LBR) BM 50 BM 50r BEARING STRENGTH (LBR) vs TIME FLOWABLE FILL 2005 ( BATCH MIX 51 )0 50 100 150 200 250 0204060 TIME(DAYS)STRENGTH(LBR) BM 51 BM 51r BEARING STRENGTH (LBR) vs TIME FLOWABLE FILL 2005 ( BATCH MIX 54 )0 50 100 150 200 250 0204060 TIME(DAYS)STRENGTH(LBR) BM 54 BM 54r BM 54Type I BEARING STRENGTH (LBR) vs TIME FLOWABLE FILL 2005 ( BATCH MIX 55 )0 50 100 150 200 250 0204060 TIME(DAYS)STRENGTH(LBR) BM 55 BM 55r BM 55rb UnConfined Compressive Stress vs TIME FLOWABLE FILL 2005 ( BATCH MIX 50 )0.00 50.00 100.00 150.00 200.00 250.00 0204060 TIME(DAYS)STRESS(PSI) BM 50 BM 50r UnConfined Compressive Stress vs TIME FLOWABLE FILL 2005 ( BATCH MIX 54 )0.00 50.00 100.00 150.00 200.00 250.00 0204060 TIME(DAYS)STRESS(PSI) BM 54 BM 54r BM 54Type I UnConfined Compressive Stress vs TIME FLOWABLE FILL 2005 ( BATCH MIX 51 )0.00 50.00 100.00 150.00 200.00 250.00 0204060 TIME(DAYS)STRESS(PSI) BM 51 BM 51r UnConfined Compressive Stress vs TIME FLOWABLE FILL 2005 ( BATCH MIX 55 )0.00 50.00 100.00 150.00 200.00 250.00 0204060 TIME(DAYS)STRESS(PSI) BM 55 BM 55r BM 55rb Figure B-6. Batch mix 50 through batch mi x 55 bearing strength, and compressive strength versus time

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192 BEARING STRENGTH (LBR) vs TIME FLOWABLE FILL 2005 ( BATCH MIX 58 )0 50 100 150 200 250 0204060 TIME(DAYS)STRENGTH(LBR) BM 58 BM 58r BEARING STRENGTH (LBR) vs TIME FLOWABLE FILL 2005 ( BATCH MIX 59 )0 50 100 150 200 250 300 0204060 TIME(DAYS)STRENGTH(LBR) BM 59 BM 59r BEARING STRENGTH (LBR) vs TIME FLOWABLE FILL 2005 ( BATCH MIX 61 )0 20 40 60 80 100 0204060 TIME(DAYS)STRENGTH(LBR) BM 61 BM 61r BEARING STRENGTH (LBR) vs TIME FLOWABLE FILL 2005 ( BATCH MIX 65 )0 20 40 60 80 100 0204060 TIME(DAYS)STRENGTH(LBR) BM 65 BM 65r UnConfined Compressive Stress vs TIME FLOWABLE FILL 2005 ( BATCH MIX 58 )0.00 50.00 100.00 150.00 200.00 250.00 0204060 TIME(DAYS)STRESS(PSI) BM 58 BM 58r UnConfined Compressive Stress vs TIME FLOWABLE FILL 2005 ( BATCH MIX 61 )0.00 50.00 100.00 150.00 200.00 250.00 0204060 TIME(DAYS)STRESS(PSI) BM 61 BM 61r UnConfined Compressive Stress vs TIME FLOWABLE FILL 2005 ( BATCH MIX 59 )0.00 50.00 100.00 150.00 200.00 250.00 0204060 TIME(DAYS)STRESS(PSI) BM 59 BM 59r UnConfined Compressive Stress vs TIME FLOWABLE FILL 2005 ( BATCH MIX 65 )0.00 50.00 100.00 150.00 200.00 250.00 0204060 TIME(DAYS)STRESS(PSI) BM 65 BM 65r Figure B-7. Batch mix 58 through batch mi x 65 bearing strength, and compressive strength versus time

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193 UnConfined Compressive Stress vs TIME FLOWABLE FILL 2005 ( BATCH MIX 69 )0.00 50.00 100.00 150.00 200.00 250.00 0204060 TIME(DAYS)STRESS(PSI) BM 69 BM 69a BM 69r BEARING STRENGTH (LBR) vs TIME FLOWABLE FILL 2005 ( BATCH MIX 69 )0.00 20.00 40.00 60.00 80.00 100.00 0204060 TIME(DAYS)STRENGTH(LBR) BM 69 BM 69a BM 69r Figure B-8. Batch mix 69 bearing strength, and compressive strength versus time

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194 Table B-1. Batch mix 4 through batch mi x 22 proctor penetrometer resistance BM#23BM#33 TimeBM 23BM 23rTimeBM 33BM 33r psipsipsipsi 6 hrs50236 hrs1817 1 day1351131 day4738 2 day 240326002 day 177-3 day11339003 day6768 28 day2600260028 day250237 56 day2600260056 day217417 BM#24BM#34 TimeBM 24BM 24rTimeBM 34BM 34r psipsipsipsi 6 hrs28--6 hrs21-1 day1701201 day77127 2 day 260026002 day 10001500 3 day9675173 day350300 28 day2600--28 day26002600 56 day2600--56 day26002600 BM#25BM#40 TimeBM 25BM 25-Type IBM 25rTimeBM 40BM 40r psipsipsipsipsi 6 hrs3516146 hrs60 1 day8353491 day147633 2 day 5331871702 day --2533 3 day140901023 day12002467 28 day110015320028 day26002600 56 day----22756 day26002600 BM#26BM#44 TimeBM 26BM 26rTimeBM 44BM 44r psipsipsipsi 6 hrs13316 hrs248 1 day502131 day350455 2 day --13672 day 26002600 3 day2003903 day7672000 28 day2600260028 day26002600 56 day2600260056 day26002600 BM#30BM#48 TimeBM 30BM 30rTimeBM 48BM 48-Type IBM 48r BM 48rbpsipsipsipsipsipsi 6 hrs23206 hrs091323 1 day702901 day167287420324 2 day 14007002 day 2600260026002600 3 day267--3 day1900186726001250 28 day213368328 day2600260026002600 56 day2600256756 day2600--26002600

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195 Table B-2. Batch mix 23 through batch mi x 48 proctor penetrometer resistance BM#23BM#33 TimeBM 23BM 23rTimeBM 33BM 33r psipsipsipsi 6 hrs50236 hrs1817 1 day1351131 day4738 2 day 240326002 day 177-3 day11339003 day6768 28 day2600260028 day250237 56 day2600260056 day217417 BM#24BM#34 TimeBM 24BM 24rTimeBM 34BM 34r psipsipsipsi 6 hrs28--6 hrs21-1 day1701201 day77127 2 day 260026002 day 10001500 3 day9675173 day350300 28 day2600--28 day26002600 56 day2600--56 day26002600 BM#25BM#40 TimeBM 25BM 25-Type IBM 25rTimeBM 40BM 40r psipsipsipsipsi 6 hrs3516146 hrs60 1 day8353491 day147633 2 day 5331871702 day --2533 3 day140901023 day12002467 28 day110015320028 day26002600 56 day----22756 day26002600 BM#26BM#44 TimeBM 26BM 26rTimeBM 44BM 44r psipsipsipsi 6 hrs13316 hrs248 1 day502131 day350455 2 day --13672 day 26002600 3 day2003903 day7672000 28 day2600260028 day26002600 56 day2600260056 day26002600 BM#30BM#48 TimeBM 30BM 30rTimeBM 48BM 48-Type IBM 48r BM 48rbpsipsipsipsipsipsi 6 hrs23206 hrs091323 1 day702901 day167287420324 2 day 14007002 day 2600260026002600 3 day267--3 day1900186726001250 28 day213368328 day2600260026002600 56 day2600256756 day2600--26002600

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196 Table B-3. Batch mix 50 through batch mi x 69 proctor penetrometer resistance BM#50BM#59 TimeBM 50BM 50rTimeBM 59BM 59r psipsipsipsi 6 hrs0--6 hrs250 1 day95--1 day24060 2 day 580--2 day 26002600 3 day233--3 day1533287 28 day1967--28 day26002600 56 day1667--56 day26002600 BM#51BM#61 TimeBM 51BM 51rTimeBM 61BM 61r psipsipsipsi 6 hrs15196 hrs00 1 day2271801 day033 2 day 260026002 day 9355 3 day11677003 day6454 28 day2600--28 day170160 56 day2600--56 day120110 BM#54BM#65 TimeBM 54BM 54-Type IBM 54rTimeBM 65BM 65r psipsipsipsipsi 6 hrs217126 hrs20 1 day1101531531 day3235 2 day 66714335502 day 110107 3 day3305174573 day4053 28 day13001400160028 day150163 56 day17002600260056 day407153 BM#55BM#69 TimeBM 55BM 55r BM 55rbTimeBM 69 BM 69aBM 69r psipsipsipsipsipsi 6 hrs2222106 hrs080 1 day3332022571 day102730 2 day 2267240026002 day 60407157 3 day13005504253 day2511364 28 day26002600260028 day93677190 56 day26002600260056 day90343115 BM#58 TimeBM 58BM 58r psipsi 6 hrs30 1 day6461 2 day 12001075 3 day110177 28 day1833883 56 day2200825

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197 Table B-4. Batch mix 4 through batch mix 22 individual 2-days oven LBR strength BM#4BM#16 Sample No.BM 4 BM 4aBM 4rSample No.BM 16 BM 16aBM 16r (LBR)(LBR)(LBR)(LBR)(LBR)(LBR) 129110160111999150 234921672104141117 335102195310783112 BM#8BM#18 Sample No.BM 8BM 8rSample No.BM 18BM 18r (LBR)(LBR)(LBR)(LBR) 1653713023 2603225026 31293533119 BM#12BM#19 Sample No.BM 12BM 12rSample No.BM 19BM 19r (LBR)(LBR)(LBR)(LBR) 116020215167 213718526698 3138203369152 BM#14BM#20 Sample No.BM 14BM 14rSample No.BM 20BM 20r (LBR)(LBR)(LBR)(LBR) 16933110396 24731271121 36632387107 BM#15BM#22 Sample No.BM 15BM 15-Type IBM 15rSample No.BM 22BM 22r (LBR)(LBR)(LBR)(LBR)(LBR) 17514613613440 2631268723649 3601649934150

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198 Table B-5. Batch mix 23 through batch mix 48 individu al 2-days oven LBR strength BM#23BM#33 Sample No.BM 23BM 23rSample No.BM 33BM 33r (LBR)(LBR)(LBR)(LBR) 17616411321 28616221224 36023331123 BM#24BM#34 Sample No.BM 24BM 24rSample No.BM 34BM 34r (LBR)(LBR)(LBR)(LBR) 11175913065 2947723377 3984532496 BM#25BM#40 Sample No.BM 25BM 25-Type IBM 25r BM 25rbSample No.BM 40BM 40r (LBR)(LBR)(LBR)(LBR)(LBR)(LBR) 1392016914458 22922151226462 34418141534660 BM#26BM#44 Sample No.BM 26BM 26rSample No.BM 44BM 44r (LBR)(LBR)(LBR)(LBR) 16653181136 23351291132 34663370131 BM#30BM#48 Sample No.BM 30BM 30rSample No.BM 48BM 48-Type IBm 48r BM 48rb(LBR)(LBR)(LBR)(LBR)(LBR)(LBR) 145421102139235230 26835291169240242 367333112125250224

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199 Table B-6. Batch mix 50 through batch mi x 69 individual 2-days oven LBR strength BM#50BM#59 Sample No.BM 50BM 50rSample No.BM 59BM 59r (LBR)(LBR)(LBR)(LBR) 12144171135 21949296109 31943378164 BM#51BM#61 Sample No.BM 51BM 51rSample No.BM 61BM 61r (LBR)(LBR)(LBR)(LBR) 18871184 281106265 398106364 BM#54BM#65 Sample No.BM 54BM 54-Type IBM 54rSample No.BM 65BM 65r (LBR)(LBR)(LBR)(LBR)(LBR) 13754491811 228494321013 3336842398 BM#55BM#69 Sample No.BM 55BM 55r BM 55rbSample No.BM 69 BM 69aBM 69r (LBR)(LBR)(LBR)(LBR)(LBR)(LBR) 1567411711339 252108119212210 3799815231811 BM#58 Sample No.BM 58BM 58r (LBR)(LBR) 14272 24760 33770

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200 APPENDIX C ANALYSIS OF VARIANCE (ANOVA), PARAMETERS, AND STANDARD ERROR FOR MODELS This appendix contains the analysis of variances (ANOVA), parameters and standard error for the models.

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201 Table C-1. Analysis of va riance (ANOVA) for 28-day_LBR Dependent Variable: y Sum of Source DF Squares Mean Square F Value Pr > F Model 14 862512.761 61608.054 62.45 <.0001 Error 159 156865.944 986.578 Corrected Total 173 1019378.705 R-Square Coeff Var Root MSE y Mean 0.846116 27.71796 31.40984 113.3195 Source DF Type I SS Mean Square F Value Pr > F a 1 651259.1367 651259.1367 660.12 <.0001 b 1 70256.1787 70256.1787 71.21 <.0001 c 1 2652.3252 2652.3252 2.69 0.1031 d 1 1876.9757 1876.9757 1.90 0.1697 a*a 1 7236.2518 7236.2518 7.33 0.0075 c*c 1 4061.4278 4061.4278 4.12 0.0441 d*d 1 78089.4362 78089.4362 79.15 <.0001 a*b 1 12646.5644 12646.5644 12.82 0.0005 a*c 1 25540.2951 25540.2951 25.89 <.0001 a*d 1 466.9930 466.9930 0.47 0.4925 b*c 1 15.7662 15.7662 0.02 0.8996 b*d 1 6183.1408 6183.1408 6.27 0.0133 c*d 1 770.7810 770.7810 0.78 0.3781 Table C-2. Parameters and st andard error for 28-day_LBR Dependent Variable: y Standard Parameter Estimate Error t Value Pr > |t| Intercept 299.0395348 549.8721856 0.55 0.5850 a 0.9275712 3.7396744 0.25 0.8044 b -18.7800976 12.5361909 -1.50 0.1361 c -24.8168169 111.9847756 -0.22 0.8249 d -3.2137849 1.8474553 -1.74 0.0839 a*a -0.0007561 0.0063013 -0.12 0.9046 c*c 1.1867884 5.1651063 0.23 0.8186 d*d 0.0791980 0.0091503 8.66 <.0001 a*b 0.0337116 0.0523819 0.64 0.5208 a*c -0.1446410 0.3919195 -0.37 0.7126 a*d -0.0042579 0.0065837 -0.65 0.5187 b*c 1.1495852 1.3251259 0.87 0.3870 b*d 0.0303699 0.0277731 1.09 0.2758 c*d -0.1140068 0.1289825 -0.88 0.3781

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202 Table C-3. Analysis of va riance (ANOVA) for 28-day_ psi Dependent Variable: y Sum of Source DF Squares Mean Square F Value Pr > F Model 14 296002.7645 21143.0546 83.50 <.0001 Error 159 40262.4392 253.2229 Corrected Total 173 336265.2037 R-Square Coeff Var Root MSE y Mean 0.880266 25.76665 15.91298 61.75805 Source DF Type I SS Mean Square F Value Pr > F a 1 242503.7096 242503.7096 957.67 <.0001 b 1 24517.8816 24517.8816 96.82 <.0001 c 1 636.4043 636.4043 2.51 0.1149 d 1 1380.3527 1380.3527 5.45 0.0208 a*a 1 0.0386 0.0386 0.00 0.9902 c*c 1 8535.1258 8535.1258 33.71 <.0001 d*d 1 10721.9032 10721.9032 42.34 <.0001 a*b 1 1984.1722 1984.1722 7.84 0.0058 a*c 1 2513.1280 2513.1280 9.92 0.0019 a*d 1 862.3962 862.3962 3.41 0.0668 b*c 1 13.4709 13.4709 0.05 0.8179 b*d 1 983.6902 983.6902 3.88 0.0505 c*d 1 1249.2885 1249.2885 4.93 0.0278 Table C-4. Parameters and st andard error for 28-day_psi Dependent Variable: y Standard Parameter Estimate Error t Value Pr > |t| Intercept 94.93413075 278.5784124 0.34 0.7324 a 1.52314981 1.8946086 0.80 0.4226 b -0.68144093 6.3511344 -0.11 0.9147 c -45.61558093 56.7341681 -0.80 0.4226 d 1.23005865 0.9359651 1.31 0.1907 a*a -0.00293926 0.0031924 -0.92 0.3586 c*c 3.36478471 2.6167665 1.29 0.2004 d*d 0.02723015 0.0046358 5.87 <.0001 a*b -0.00963500 0.0265379 -0.36 0.7170 a*c -0.06353336 0.1985558 -0.32 0.7494 a*d -0.01002679 0.0033354 -3.01 0.0031 b*c 0.23249384 0.6713405 0.35 0.7296 b*d -0.04175278 0.0140705 -2.97 0.0035 c*d -0.14514315 0.0653456 -2.22 0.0278

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203 Table C-5. Analysis of va riance (ANOVA) for 56-day_LBR Dependent Variable: y Sum of Source DF Squares Mean Square F Value Pr > F Model 14 1178376.169 84169.726 66.05 <.0001 Error 159 202620.036 1274.340 Corrected Total 173 1380996.205 R-Square Coeff Var Root MSE y Mean 0.853280 25.82166 35.69790 138.2479 Source DF Type I SS Mean Square F Value Pr > F a 1 840033.6997 840033.6997 659.19 <.0001 b 1 223774.7389 223774.7389 175.60 <.0001 c 1 5182.3226 5182.3226 4.07 0.0454 d 1 8627.5518 8627.5518 6.77 0.0101 a*a 1 12347.3759 12347.3759 9.69 0.0022 c*c 1 7.2247 7.2247 0.01 0.9401 d*d 1 45713.3847 45713.3847 35.87 <.0001 a*b 1 10905.5611 10905.5611 8.56 0.0039 a*c 1 15991.9762 15991.9762 12.55 0.0005 a*d 1 529.9691 529.9691 0.42 0.5199 b*c 1 849.0476 849.0476 0.67 0.4156 b*d 1 11770.6426 11770.6426 9.24 0.0028 c*d 1 2042.5995 2042.5995 1.60 0.2073 Table C-6. Parameters and st andard error for 56-day_LBR Dependent Variable: y Standard Parameter Estimate Error t Value Pr > |t| Intercept 917.4226386 624.9404162 1.48 0.1404 a -4.0290194 4.2502125 -0.95 0.3446 b -33.6380609 14.2476244 -2.36 0.0194 c -129.9300854 127.2728719 -1.02 0.3089 d -1.7668111 2.0996689 -0.84 0.4013 a*a 0.0084004 0.0071616 1.17 0.2426 c*c 4.9638498 5.8702436 0.85 0.3990 d*d 0.0601406 0.0103995 5.78 <.0001 a*b 0.0918923 0.0595331 1.54 0.1247 a*c 0.3590576 0.4454241 0.81 0.4214 a*d -0.0037313 0.0074825 -0.50 0.6187 b*c 2.6016943 1.5060313 1.73 0.0860 b*d 0.0375033 0.0315647 1.19 0.2365 c*d -0.1855909 0.1465912 -1.27 0.2073

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204 Table C-7. Analysis of va riance (ANOVA) for 56-day_psi Dependent Variable: y Sum of Source DF Squares Mean Square F Value Pr > F Model 14 366547.1182 26181.9370 68.94 <.0001 Error 159 60385.4411 379.7826 Corrected Total 173 426932.5593 R-Square Coeff Var Root MSE y Mean 0.858560 24.21001 19.48801 80.49569 Source DF Type I SS Mean Square F Value Pr > F a 1 335819.4915 335819.4915 884.24 <.0001 b 1 2795.4529 2795.4529 7.36 0.0074 c 1 2995.0574 2995.0574 7.89 0.0056 d 1 9.3865 9.3865 0.02 0.8753 a*a 1 138.2629 138.2629 0.36 0.5471 c*c 1 1787.7336 1787.7336 4.71 0.0315 d*d 1 9314.4984 9314.4984 24.53 <.0001 a*b 1 496.2811 496.2811 1.31 0.2547 a*c 1 11854.8823 11854.8823 31.21 <.0001 a*d 1 42.2716 42.2716 0.11 0.7391 b*c 1 988.1203 988.1203 2.60 0.1087 b*d 1 89.4557 89.4557 0.24 0.6281 c*d 1 6.2337 6.2337 0.02 0.8982 Table C-8. Parameters and st andard error for 56-day_psi Dependent Variable: y Standard Parameter Estimate Error t Value Pr > |t| Intercept 152.8311117 341.1642685 0.46 0.6453 a -0.2440199 2.3202542 -0.11 0.9164 b -14.1298028 7.7779901 -1.82 0.0712 c -1.5069197 69.4801538 -0.02 0.9827 d -1.4146273 1.1462405 -1.23 0.2190 a*a 0.0013497 0.0039096 0.35 0.7304 c*c -1.2148056 3.2046533 -0.38 0.7051 d*d 0.0289481 0.0056773 5.10 <.0001 a*b 0.0527250 0.0325000 1.62 0.1067 a*c 0.0130316 0.2431637 0.05 0.9573 a*d -0.0005653 0.0040848 -0.14 0.8901 b*c 1.1438790 0.8221649 1.39 0.1661 b*d -0.0041910 0.0172316 -0.24 0.8082 c*d 0.0102527 0.0800263 0.13 0.8982

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205 Table C-9. Analysis of variance (ANOVA) for percent volume change Dependent Variable: y Sum of Source DF Squares Mean Square F Value Pr > F Model 14 95.1002556 6.7928754 15.26 <.0001 Error 159 70.7689599 0.4450878 Corrected Total 173 165.8692155 R-Square Coeff Var Root MSE y Mean 0.573345 62.39830 0.667149 1.069178 Source DF Type I SS Mean Square F Value Pr > F a 1 0.66668565 0.66668565 1.50 0.2228 b 1 23.28073600 23.28073600 52.31 <.0001 c 1 20.21083693 20.21083693 45.41 <.0001 d 1 20.97958837 20.97958837 47.14 <.0001 a*a 1 1.19723827 1.19723827 2.69 0.1030 c*c 1 19.71027092 19.71027092 44.28 <.0001 d*d 1 0.07402647 0.07402647 0.17 0.6840 a*b 1 0.74268437 0.74268437 1.67 0.1983 a*c 1 3.73650570 3.73650570 8.39 0.0043 a*d 1 2.48076185 2.48076185 5.57 0.0194 b*c 1 0.02362357 0.02362357 0.05 0.8181 b*d 1 0.74311573 0.74311573 1.67 0.1982 c*d 1 1.17469349 1.17469349 2.64 0.1062 Table C-10. Parameters and standard error for percent volume change Dependent Variable: y Standard Parameter Estimate Error t Value Pr > |t| Intercept -3.945266055 11.67935406 -0.35 0.7248 a -0.004565043 0.07943115 -0.06 0.9542 b 0.193485690 0.26627026 0.73 0.4685 c -0.667434645 2.37857065 -0.28 0.7794 d 0.028359595 0.03924018 0.72 0.4709 a*a 0.000010491 0.00013384 0.08 0.9376 c*c 0.037335267 0.10970750 0.34 0.7341 d*d -0.000184863 0.00019435 -0.95 0.3430 a*b -0.000115511 0.00111260 -0.10 0.9174 a*c 0.009037169 0.00832442 1.09 0.2793 a*d -0.000070018 0.00013984 -0.50 0.6173 b*c 0.012815636 0.02814584 0.46 0.6495 b*d -0.000164766 0.00058990 -0.28 0.7804 c*d -0.004450691 0.00273961 -1.62 0.1062

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206 Table C-11. Comparison of measured laborat ory results and predicted LBR strength results measuredpredictedmeasuredpredicted Lab resultsresultsLab resultsresults Batch MixCementw/cMineral Air Content (%) 28-day28-day56-day56-day NumberContent ratioAdmixturesTargetAchievedstrengthstrengthstrengthstrength (lb/yd 3 ) (%) (LBR) (LBR) (LBR) (LBR) 42002.007.5% 2.5%22.005213749130 25509.007.5% 2.5%5.204511670102 151504.507.5% 2.5%7.60140171200198 231504.5507.5% 2.5%5.50148177223218 501004.5017.5% 2.5%17.0056576259 162004.507.5% 2.5%1.30242227337282 61509.0017.5% 2.5%20.0017161519 341009.0507.5% 2.5%1.0010388117115 242004.5507.5% 2.5%1.20190199266267 591504.55017.5% 2.5%4.80230182270222 581004.55017.5% 2.5%18.0077658182 511504.5017.5% 2.5%7.80219169190197 69509.05017.5% 2.5%40.006-836-50 261009.007.5% 2.5%1.40110119126153 402002.0017.5% 2.5%20.00142157118150 16a2004.507.5% 2.5%0.80281231223284 141004.507.5% 2.5%15.0090788085 82002.0207.5% 2.5%21.00120106123122 301009.0207.5% 2.5%2.006756110102 181004.5207.5% 2.5%13.0081559985 202004.5207.5% 2.5%0.60131173192242 442002.02017.5% 2.5%15.20112159142176 65509.02017.5% 2.5%15.001221610 541004.52017.5% 2.5%16.0036267349 551504.52017.5% 2.5%7.40123121220166 122002.0507.5% 2.5%15.00188212237235 221004.5507.5% 2.5%18.0060658182 33509.0507.5% 2.5%18.5021303131 191504.5207.5% 2.5%4.50111144198188 482002.05017.5% 2.5%25.00173129173153 4a2002.007.5% 2.5%16.00192196168190 69a509.05017.5% 2.5%17.0032383536 8r2002.0207.5% 2.5%24.5058746890 16r2004.507.5% 2.5%0.50268233290285 30r1009.0207.5% 2.5%2.005556122102 18r1004.5207.5% 2.5%15.5040315355 14r1004.507.5% 2.5%13.00509879110 22r1004.5507.5% 2.5%19.5053527465 33r509.0507.5% 2.5%17.5032353834 23r1504.5507.5% 2.5%7.10156166226208 15-Type I1504.507.5% 2.5%7.00145176205203 54-Type I1004.52017.5% 2.5%15.00573610961 25-Type I509.007.5% 2.5%20.0030163219 48-Type I2002.05017.5% 2.5%20.00173170190194 25r509.007.5% 2.5%17.0026363036 34r1009.0507.5% 2.5%2.508782114116 69r509.05017.5% 2.5%20.0015221425 26r1009.007.5% 2.5%1.00101122153153 40r2002.0017.5% 2.5%24.00121118123110 19r1504.5207.5% 2.5%6.10117132152176 44r2002.02017.5% 2.5%18.00161133175150 48r2002.05017.5% 2.5%15.00254212282235 55r1504.52017.5% 2.5%3.20164155162197 54r1004.52017.5% 2.5%14.50524011267 4r2002.007.5% 2.5%15.00202205245200 58r1004.55017.5% 2.5%16.5042784498 12r2002.0507.5% 2.5%12.00242236216259 15r1504.507.5% 2.5%5.20184191212218 20r2004.5207.5% 2.5%1.10143169238241 65r509.02017.5% 2.5%17.0016-11140 61r509.0017.5% 2.5%21.001291213 59r1504.55017.5% 2.5%6.30151171181213 51r1504.5017.5% 2.5%8.00181167205195 24r2004.5507.5% 2.5%1.70207196263266 50r1004.5017.5% 2.5%19.0042374734 25rb509.007.5% 2.5%17.0019363636 48rb2002.05017.5% 2.5%14.50225216261239 55r b 1504.52017.5% 2.5%5.70158135189179

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207 Table C-12. Comparison of measured laborat ory results and predicted compressive strength results measuredpredictedmeasuredpredicted Lab resultsresultsLab resultsresults Batch MixCementw/cMineral Air Content (%) 28-day28-day56-day56-day NumberContent ratioAdmixturesTargetAchievedstrengthstrengthstrengthstrength (lb/yd3) (%) (psi) (psi) (psi) (psi) 42002.007.5% 2.5%22.005013241127 25509.007.5% 2.5%5.201722932 151504.507.5% 2.5%7.60586993116 231504.5507.5% 2.5%5.507982124117 501004.5017.5% 2.5%17.0045423953 162004.507.5% 2.5%1.308986133140 61509.0017.5% 2.5%20.0014161714 341009.0507.5% 2.5%1.0030354446 242004.5507.5% 2.5%1.207980155138 591504.55017.5% 2.5%4.808984111117 581004.55017.5% 2.5%18.0066517247 511504.5017.5% 2.5%7.806769108116 69509.05017.5% 2.5%40.009-108-14 261009.007.5% 2.5%1.4022233444 402002.0017.5% 2.5%20.00138136114129 16a2004.507.5% 2.5%0.807086148140 141004.507.5% 2.5%15.0058436961 82002.0207.5% 2.5%21.00100106129108 301009.0207.5% 2.5%2.0014113428 181004.5207.5% 2.5%13.0033364350 202004.5207.5% 2.5%0.608669132121 442002.02017.5% 2.5%15.20107123114116 65509.02017.5% 2.5%15.004-283 541004.52017.5% 2.5%16.0039324639 551504.52017.5% 2.5%7.4081558198 122002.0507.5% 2.5%15.00143130139130 221004.5507.5% 2.5%18.0042513747 33509.0507.5% 2.5%18.5013151517 191504.5207.5% 2.5%4.505661132101 482002.05017.5% 2.5%25.0010988135114 4a2002.007.5% 2.5%16.00115144105135 69a509.05017.5% 2.5%17.0019172419 8r2002.0207.5% 2.5%24.50639557103 16r2004.507.5% 2.5%0.506487132139 30r1009.0207.5% 2.5%2.0018113828 18r1004.5207.5% 2.5%15.5035323741 14r1004.507.5% 2.5%13.0040446568 22r1004.5507.5% 2.5%19.5038475141 33r509.0507.5% 2.5%17.5015161818 23r1504.5507.5% 2.5%7.107477127114 15-Type I1504.507.5% 2.5%7.006270101116 54-Type I1004.52017.5% 2.5%15.0033336743 25-Type I509.007.5% 2.5%20.0015161614 48-Type I2002.05017.5% 2.5%20.00143109139122 25r509.007.5% 2.5%17.008131517 34r1009.0507.5% 2.5%2.5031335148 69r509.05017.5% 2.5%20.0015131514 26r1009.007.5% 2.5%1.0021234743 40r2002.0017.5% 2.5%24.00151127131124 19r1504.5207.5% 2.5%6.10405812999 44r2002.02017.5% 2.5%18.00139115131112 48r2002.05017.5% 2.5%15.00162130162130 55r1504.52017.5% 2.5%3.20536498103 54r1004.52017.5% 2.5%14.5033345644 4r2002.007.5% 2.5%15.00159147161136 58r1004.55017.5% 2.5%16.5043554153 12r2002.0507.5% 2.5%12.00137143143134 15r1504.507.5% 2.5%5.206672136118 20r2004.5207.5% 2.5%1.109267129122 65r509.02017.5% 2.5%17.005-2241 61r509.0017.5% 2.5%21.0010171113 59r1504.55017.5% 2.5%6.30977999115 51r1504.5017.5% 2.5%8.0010269170115 24r2004.5507.5% 2.5%1.705778125139 50r1004.5017.5% 2.5%19.0036414446 25rb509.007.5% 2.5%17.007131617 48r b 2002.05017.5% 2.5%14.50131132119130 55rb1504.52017.5% 2.5%5.704959100100

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208 Table C-13. Comparison of measured laborat ory results and predicted percent volume change results measuredpredicted Lab resultsresults Batch MixCementw/cMineral Air Content (%) Volume Volume NumberContent ratioAdmixturesTargetAchievedchangechange (lb/yd3) (%) (%) (%) 42002.007.5% 2.5%22.000.142.29 25509.007.5% 2.5%5.200.14-1.49 151504.507.5% 2.5%7.600.601.23 231504.5507.5% 2.5%5.500.190.13 501004.5017.5% 2.5%17.002.861.59 162004.507.5% 2.5%1.302.101.75 61509.0017.5% 2.5%20.002.892.99 341009.0507.5% 2.5%1.000.26-0.25 242004.5507.5% 2.5%1.200.310.97 591504.55017.5% 2.5%4.800.79-0.03 581004.55017.5% 2.5%18.001.411.28 511504.5017.5% 2.5%7.800.981.28 69509.05017.5% 2.5%40.001.827.49 261009.007.5% 2.5%1.401.661.27 402002.0017.5% 2.5%20.002.121.90 16*2004.507.5% 2.5%0.802.101.63 141004.507.5% 2.5%15.000.351.11 82002.0207.5% 2.5%21.003.112.06 301009.0207.5% 2.5%2.000.161.00 181004.5207.5% 2.5%13.000.570.54 202004.5207.5% 2.5%0.601.381.40 442002.02017.5% 2.5%15.201.330.95 65509.02017.5% 2.5%15.001.391.05 541004.52017.5% 2.5%16.000.521.25 551504.52017.5% 2.5%7.401.061.05 122002.0507.5% 2.5%15.000.290.61 221004.5507.5% 2.5%18.000.541.28 33509.0507.5% 2.5%18.500.461.16 191504.5207.5% 2.5%4.500.380.38 482002.05017.5% 2.5%25.000.542.48 4*2002.007.5% 2.5%16.000.141.12 69*509.05017.5% 2.5%17.001.820.72 8r2002.0207.5% 2.5%24.503.112.73 16r2004.507.5% 2.5%0.502.101.56 30r1009.0207.5% 2.5%2.000.161.00 18r1004.5207.5% 2.5%15.500.571.13 14r1004.507.5% 2.5%13.000.350.63 22r1004.5507.5% 2.5%19.500.541.63 33r509.0507.5% 2.5%17.500.460.87 23r1504.5507.5% 2.5%7.100.190.49 15-Type I1504.507.5% 2.5%7.000.311.09 54-Type I1004.52017.5% 2.5%15.000.251.01 25-Type I509.007.5% 2.5%20.000.892.99 48-Type I2002.05017.5% 2.5%20.001.261.55 25r509.007.5% 2.5%17.000.412.08 34r1009.0507.5% 2.5%2.500.260.18 69r509.05017.5% 2.5%20.001.821.60 26r1009.007.5% 2.5%1.001.661.15 40r2002.0017.5% 2.5%24.002.122.68 19r1504.5207.5% 2.5%6.100.380.75 44r2002.02017.5% 2.5%18.001.331.49 48r2002.05017.5% 2.5%15.000.540.61 55r1504.52017.5% 2.5%3.201.060.08 54r1004.52017.5% 2.5%14.500.520.90 4r2002.007.5% 2.5%15.000.140.92 58r1004.55017.5% 2.5%16.501.410.94 12r2002.0507.5% 2.5%12.000.290.05 15r1504.507.5% 2.5%5.200.600.67 20r2004.5207.5% 2.5%1.101.381.51 65r509.02017.5% 2.5%17.001.391.65 61r509.0017.5% 2.5%21.003.893.29 59r1504.55017.5% 2.5%6.300.790.31 51r1504.5017.5% 2.5%8.000.981.33 24r2004.5507.5% 2.5%1.700.311.08 50r1004.5017.5% 2.5%19.002.862.07 25r*509.007.5% 2.5%17.000.172.08 48r*2002.05017.5% 2.5%14.500.400.52 55r*1504.52017.5% 2.5%5.700.440.66

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209 R2 = 0.846 0.00 50.00 100.00 150.00 200.00 250.00 300.00 0.0050.00100.00150.00200.00250.00300.00 Measured Strength, LBRPredicted Strength, LBR Figure C-1. Comparison of measured labor atory results and predicted 28-day LBR strength R2 = 0.880 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 180.00 0.0020.0040.0060.0080.00100.00120.00140.00160.00180.00 Measured Strength, psiPredicted Strength, psi Figure C-2. Comparison of measured la boratory results and predicted 28-day compressive strength

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210 R2 = 0.853 0.00 50.00 100.00 150.00 200.00 250.00 300.00 350.00 0.0050.00100.00150.00200.00250.00300.00350.00400.00 Measured Strength, LBRPredicted Strength, LBR Figure C-3. Comparison of measured labor atory results and predicted 56-day LBR strength R2 = 0.859 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 180.00 0.0020.0040.0060.0080.00100.00120.00140.00160.00180.00 Measured Strength, psiPredicted Strength, psi Figure C-4. Comparison of measured la boratory results and predicted 56-day compressive strength

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211 R2 = 0.573 0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 0.000.501.001.502.002.503.003.504.004.50 Measured Volume Change, %Predicted Volume Change, % Figure C-5. Comparison of m easured laboratory results and predicted percent volume change results

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212Table C-14. Computed sand-to-water (s/w) ra tio for varying strength prediction models trend chart at fixed air (15%) and fixed 0% mineral admixture w/c ratio 0.51.52.53.54.55.56.57.58.59.510.511.512.513.514.5 0 10 20 30 6.616.06 40 7.196.265.494.844.283.87 50 6.135.214.463.853.332.892.56 60 6.905.634.663.893.272.762.331.96 70 7.005.524.433.602.952.411.98 80 5.784.483.542.812.241.77 906.484.833.682.842.20 1005.554.073.042.28 1106.914.793.442.511.82 1206.104.162.922.07 1305.413.622.49 1404.823.162.11 1507.084.312.761.78 1606.453.862.42 1705.903.462.11 1805.413.111.83 1904.972.80 2004.572.51 Note: Shaded cells signify sand-to-water (s /w) ratio falls within the 1.73 to 7.20 range Cement Content (lb/yd 3 )

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213Table C-15. Computed sand-to-water (s/w) ra tio for varying strength prediction models trend chart at fixed air (8%) and fixed 20% fly ash mineral admixture w/c ratio 0.51.52.53.54.55.56.57.58.59.510.511.512.513.514.5 0 10 20 30 40 6.986.145.444.844.39 50 6.845.845.034.373.813.332.97 60 6.295.244.413.743.192.722.322.03 70 6.174.994.103.392.822.341.94 80 6.445.054.023.242.622.12 907.205.414.183.272.572.03 1006.194.593.482.662.04 1105.373.922.912.17 1206.774.683.352.431.76 1306.034.102.882.03 1405.393.612.47 1504.833.172.12 1607.144.352.801.81 1706.543.922.46 1806.013.542.17 1905.533.201.90 2005.102.89 Note: Shaded cells signify s/w ratio do es not fall within the 1.73 to 7.20 range Cement Content (lb/yd 3 )

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214Table C-16. Computed sand-to-water (s/w) ra tio for varying strength prediction models trend chart at fixed air (10%) and fixed 50% ground granulated blast-furnace slag mineral admixture 0.51.52.53.54.55.56.57.58.59.510.511.512.513.514.5 0 10 20 30 7.116.53 40 6.735.925.244.654.22 50 6.595.624.834.193.643.182.83 60 6.055.034.223.573.032.582.191.9 70 5.924.783.913.222.662.21.82 80 6.184.833.833.072.471.99 906.915.183.973.092.421.89 1005.934.373.292.501.90 1105.123.712.742.02 1206.474.453.162.27 1305.743.882.701.88 1405.113.392.30 1504.572.971.95 1606.794.102.60 1706.203.682.28 1805.683.311.99 1905.212.97 2004.792.67 Note: Shaded cells signify s/w ratio do es not fall within the 1.73 to 7.20 range Cement Content (lb/yd 3 ) w/c ratio

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215 APPENDIX D ESTIMATED 28AND 56-DAY STRENGTH This appendix contains plots of esti mated 28and 56-day LBR and compressive strength.

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216 0.00 50.00 100.00 150.00 200.00 250.00 300.00 050100150200250 Cement content, lbs/yd3Strength, LBR 2% 3% 4% 5% 6% Figure D-1. Estimated 28-day LBR strength vs. cement content at fixed air content (2% through 6%) and fixed 0% mineral admixture 0.00 50.00 100.00 150.00 200.00 250.00 300.00 350.00 024681012 w/c ratioStrength, LBR 2% 3% 4% 5% 6% Figure D-2. Estimated 28-day LBR strength vs. w/c ratio at fixed air content (2% through 6%) and fixed 0% mineral admixture

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217 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 050100150200250 Cement content, lbs/yd3Strength, psi 2% 3% 4% 5% 6% Figure D-3. Estimated 28-day compressive st rength vs. cement content at fixed air content (2% through 6%) and fi xed 0% mineral admixture 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 024681012 w/c ratioStrength, psi 2% 3% 4% 5% 6% Figure D-4. Estimated 28-day compressive stre ngth vs. w/c ratio at fixed air content (2% through 6%) and fixed 0% mineral admixture

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218 0.00 50.00 100.00 150.00 200.00 250.00 050100150200250 Cement content, lbs/yd3Strength, LBR 7% 8% 9% 10% 11% Figure D-5. Estimated 28-day LBR strength vs. cement content at fixed air content (7% through 11%) and fixed 0% mineral admixture 0.00 50.00 100.00 150.00 200.00 250.00 300.00 024681012 w/c ratioStrength, LBR 7% 8% 9% 10% 11% Figure D-6. Estimated 28-day LBR strength vs. w/c ratio at fixed air content (7% through 11%) and fixed 0% mineral admixture

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219 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 050100150200250 Cement content, lbs/yd3Strength, psi 7% 8% 9% 10% 11% Figure D-7. Estimated 28-day compressive st rength vs. cement content at fixed air content (7% through 11%) and fixed 0% mineral admixture 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 024681012 w/c ratioStrength, psi 7% 8% 9% 10% 11% Figure D-8. Estimated 28-day compressive stre ngth vs. w/c ratio at fixed air content (7% through 11%) and fixed 0% mineral admixture

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220 0.00 50.00 100.00 150.00 200.00 250.00 050100150200250 Cement content, lbs/yd3Strength, LBR 12% 13% 14% 15% Figure D-9. Estimated 28-day LBR strength vs. cement content at fixed air content (12% through 15%) and fixed 0% mineral admixture 0.00 50.00 100.00 150.00 200.00 250.00 0.002.004.006.008.0010.0012.00 w/c ratioStrength, LBR 12% 13% 14% 15% Figure D-10. Estimated 28-day LBR streng th vs. w/c ratio at fixed air content (12% through 15%) and fixed 0% mineral admixture

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221 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 0 50 100 150 200 250 Cement content, lbs/yd3Strength, psi 12% 13% 14% 15% Figure D-11. Estimated 28-day compressive strength vs. cement content at fixed air content (12% through 15%) and fixed 0% mineral admixture 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 024681012 w/c ratioStrength, psi 12% 13% 14% 15% Figure D-12. Estimated 28-day compressive st rength vs. w/c ratio at fixed air content (12% through 15%) and fixe d 0% mineral admixture

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222 0.00 50.00 100.00 150.00 200.00 250.00 050100150200250 Cement content, lbs/yd3Strength, LBR 2% 3% 4% 5% 6% Figure D-13. Estimated 28-day LBR strength vs. cement content at fixed air content (2% through 6%) and fixed 20% fly ash mineral admixture 0.00 50.00 100.00 150.00 200.00 250.00 300.00 024681012 w/c ratioStrength, LBR 2% 3% 4% 5% 6% Figure D-14. Estimated 28-day LBR strength vs. w/c ratio at fixed air content (2% through 6%) and fixed 20% fly ash mineral admixture

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223 0.00 20.00 40.00 60.00 80.00 100.00 120.00 050100150200250 Cement content, lbs/yd3Strength, psi 2% 3% 4% 5% 6% Figure D-15. Estimated 28-day compressive strength vs. cement content at fixed air content (2% through 6%) and fixed 20% fly ash mineral admixture 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 024681012 w/c ratioStrength, psi 2% 3% 4% 5% 6% Figure D-16. Estimated 28-day compressive st rength vs. w/c ratio at fixed air content (2% through 6%) and fixed 20% fly ash mineral admixture

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224 0.00 50.00 100.00 150.00 200.00 250.00 050100150200250 Cement content, lbs/yd3Strength, LBR 7% 8% 9% 10% 11% Figure D-17. Estimated 28-day LBR strength vs. cement content at fixed air content (7% through 11%) and fixed 20% fl y ash mineral admixture 0.00 50.00 100.00 150.00 200.00 250.00 024681012 w/c ratioStrength, LBR 7% 8% 9% 10% 11% Figure D-18. Estimated 28-day LBR strength vs. w/c ratio at fixed air content (7% through 11%) and fixed 20% fl y ash mineral admixture

PAGE 243

225 0.00 20.00 40.00 60.00 80.00 100.00 120.00 050100150200250 Cement content, lbs/yd3Strength, psi 7% 8% 9% 10% 11% Figure D-19. Estimated 28-day compressive strength vs. cement content at fixed air content (7% through 11%) and fixe d 20% fly ash mineral admixture 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 024681012 w/c ratioStrength, psi 7% 8% 9% 10% 11% Figure D-20. Estimated 28-day compressive st rength vs. w/c ratio at fixed air content (7% through 11%) and fixed 20% fly ash mineral admixture

PAGE 244

226 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 050100150200250 Cement content, lbs/yd3Strength, LBR 12% 13% 14% 15% Figure D-21. Estimated 28-day LBR strength vs. cement content at fixed air content (12% through 15%) and fixed 20% fly ash mineral admixture 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 180.00 024681012 w/c ratioStrength, LBR 12% 13% 14% 15% Figure D-22. Estimated 28-day LBR strength vs. w/c ratio at fixed air content (12% through 15%) and fixed 20% fl y ash mineral admixture

PAGE 245

227 0.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00 80.00 90.00 100.00 050100150200250 Cement content, lbs/yd3Strength, psi 12% 13% 14% 15% Figure D-23. Estimated 28-day compressive strength vs. cement content at fixed air content (12% through 15%) and fixe d 20% fly ash mineral admixture 0.00 20.00 40.00 60.00 80.00 100.00 120.00 024681012 w/c ratioStrength, psi 12% 13% 14% 15% Figure D-24. Estimated 28-day compressive st rength vs. w/c ratio at fixed air content (12% through 15%) and fixed 20% fly ash mineral admixture

PAGE 246

228 0.00 50.00 100.00 150.00 200.00 250.00 300.00 050100150200250 Cement content, lbs/yd3Strength, LBR 2% 3% 4% 5% 6% Figure D-25. Estimated 28-day LBR strength vs. cement content at fixed air content (2% through 6%) and fixed 50% ground granul ated blast-furnace slag mineral admixture 0.00 50.00 100.00 150.00 200.00 250.00 300.00 350.00 024681012 w/c ratioStrength, LBR 2% 3% 4% 5% 6% Figure D-26. Estimated 28-day LBR strength vs. w/c ratio at fixed air content (2% through 6%) and fixed 50% ground granul ated blast-furnace slag mineral admixture

PAGE 247

229 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 050100150200250 Cement content, lbs/yd3Strength, psi 2% 3% 4% 5% 6% Figure D-27. Estimated 28-day compressive strength vs. cement content at fixed air content (2% through 6%) and fixed 50% ground granulated blast-furnace slag mineral admixture 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 180.00 024681012 w/c ratioStrength, psi 2% 3% 4% 5% 6% Figure D-28. Estimated 28-day compressive st rength vs. w/c ratio at fixed air content (2% through 6%) and fixed 50% grou nd granulated blast-furnace slag mineral admixture

PAGE 248

230 0.00 50.00 100.00 150.00 200.00 250.00 050100150200250 Cement content, lbs/yd3Strength, LBR 7% 8% 9% 10% 11% Figure D-29. Estimated 28-day LBR strength vs. cement content at fixed air content (7% through 11%) and fixed 50% ground gra nulated blast-furnace slag mineral admixture 0 50 100 150 200 250 300 024681012 w/c ratioStrength, LBR 7% 8% 9% 10% 11% Figure D-30. Estimated 28-day LBR strength vs. w/c ratio at fixed air content (7% through 11%) and fixed 50% ground gra nulated blast-furnace slag mineral admixture

PAGE 249

231 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 050100150200250 Cement content, lbs/yd3Strength, psi 7% 8% 9% 10% 11% Figure D-31. Estimated 28-day compressive strength vs. cement content at fixed air content (7% through 11%) and fixed 50% ground granulated blast-furnace slag mineral admixture 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 024681012 w/c ratioStrength, psi 7% 8% 9% 10% 11% Figure D-32. Estimated 28-day compressive st rength vs. w/c ratio at fixed air content (7% through 11%) and fixed 50% ground granulated blast-furnace slag mineral admixture

PAGE 250

232 0.00 50.00 100.00 150.00 200.00 250.00 050100150200250 Cement content, lbs/yd3Strength, LBR 12% 13% 14% 15% Figure D-33. Estimated 28-day LBR strength vs. cement content at fixed air content (12% through 15%) and fixed 50% gr ound granulated blast-furnace slag mineral admixture 0 50 100 150 200 250 024681012 w/c ratioStrength, LBR 12% 13% 14% 15% Figure D-34. Estimated 28-day LBR strength vs. w/c ratio at fixed air content (12% through 15%) and fixed 50% ground gra nulated blast-furnace slag mineral admixture

PAGE 251

233 0.00 20.00 40.00 60.00 80.00 100.00 120.00 050100150200250 Cement content, lbs/yd3Strength, psi 12% 13% 14% 15% Figure D-35. Estimated 28-day compressive strength vs. cement content at fixed air content (12% through 15%) and fixed 50% ground granulated blast-furnace slag mineral admixture 0 20 40 60 80 100 120 140 024681012 w/c ratioStrength, psi 12% 13% 14% 15% Figure D-36. Estimated 28-day compressive st rength vs. w/c ratio at fixed air content (12% through 15%) and fixed 50% gr ound granulated blast-furnace slag mineral admixture

PAGE 252

234 0.00 50.00 100.00 150.00 200.00 250.00 300.00 350.00 050100150200250 Cement content, lbs/yd3Strength, LBR 2% 3% 4% 5% 6% Figure D-37. Estimated 56-day LBR strength vs. cement content at fixed air content (2% through 6%) and fixed 0% mineral admixture 0.00 50.00 100.00 150.00 200.00 250.00 300.00 350.00 024681012 w/c ratioStrength, LBR 2% 3% 4% 5% 6% Figure D-38. Estimated 56-day LBR strength vs. w/c ratio at fixed air content (2% through 6%) and fixed 0% mineral admixture

PAGE 253

235 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 050100150200250 Cement content, lbs/yd3Strength, psi 2% 3% 4% 5% 6% Figure D-39. Estimated 56-day compressive strength vs. cement content at fixed air content (2% through 6%) and fi xed 0% mineral admixture 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 024681012 w/c ratioStrength, psi 2% 3% 4% 5% 6% Figure D-40. Estimated 56-day compressive st rength vs. w/c ratio at fixed air content (2% through 6%) and fixed 0% mineral admixture

PAGE 254

236 0.00 50.00 100.00 150.00 200.00 250.00 300.00 050100150200250 Cement content, lbs/yd3Strength, LBR 7% 8% 9% 10% 11% Figure D-41. Estimated 56-day LBR strength vs. cement content at fixed air content (7% through 11%) and fixed 0% mineral admixture 0.00 50.00 100.00 150.00 200.00 250.00 300.00 024681012 w/c ratioStrength, LBR 7% 8% 9% 10% 11% Figure D-42. Estimated 56-day LBR strength vs. w/c ratio at fixed air content (7% through 11%) and fixed 0% mineral admixture

PAGE 255

237 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 050100150200250 Cement content, lbs/yd3Strength, psi 7% 8% 9% 10% 11% Figure D-43. Estimated 56-day compressive strength vs. cement content at fixed air content (7% through 11%) and fixed 0% mineral admixture 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 024681012 w/c ratioStrength, psi 7% 8% 9% 10% 11% Figure D-44. Estimated 56-day compressive st rength vs. w/c ratio at fixed air content (7% through 11%) and fixed 0% mineral admixture

PAGE 256

238 0.00 50.00 100.00 150.00 200.00 250.00 050100150200250 Cement content, lbs/yd3Strength, LBR 12% 13% 14% 15% Figure D-45. Estimated 56-day LBR strength vs. cement content at fixed air content (12% through 15%) and fixe d 0% mineral admixture 0.00 50.00 100.00 150.00 200.00 250.00 024681012 w/c ratioStrength, LBR 12% 13% 14% 15% Figure D-46. Estimated 56-day LBR strength vs. w/c ratio at fixed air content (12% through 15%) and fixed 0% mineral admixture

PAGE 257

239 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 050100150200250 Cement content, lbs/yd3Strength, psi 12% 13% 14% 15% Figure D-47. Estimated 56-day compressive strength vs. cement content at fixed air content (12% through 15%) and fixed 0% mineral admixture 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 024681012 w/c ratioStrength, psi 12% 13% 14% 15% Figure D-48. Estimated 56-day compressive st rength vs. w/c ratio at fixed air content (12% through 15%) and fixe d 0% mineral admixture

PAGE 258

240 0.00 50.00 100.00 150.00 200.00 250.00 300.00 050100150200250 Cement content, lbs/yd3Strength, LBR 2% 3% 4% 5% 6% Figure D-49. Estimated 56-day LBR strength vs. cement content at fixed air content (2% through 6%) and fixed 20% fly ash mineral admixture 0.00 50.00 100.00 150.00 200.00 250.00 300.00 024681012 w/c ratioStrength, LBR 2% 3% 4% 5% 6% Figure D-50. Estimated 56-day LBR strength vs. w/c ratio at fixed air content (2% through 6%) and fixed 20% fly ash mineral admixture

PAGE 259

241 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 050100150200250 Cement content, lbs/yd3Strength, psi 2% 3% 4% 5% 6% Figure D-51. Estimated 56-day compressive strength vs. cement content at fixed air content (2% through 6%) and fixed 20% fly ash mineral admixture 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 024681012 w/c ratioStrength, psi 2% 3% 4% 5% 6% Figure D-52. Estimated 56-day compressive st rength vs. w/c ratio at fixed air content (2% through 6%) and fixed 20% fly ash mineral admixture

PAGE 260

242 0.00 50.00 100.00 150.00 200.00 250.00 050100150200250 Cement content, lbs/yd3Strength, LBR 7% 8% 9% 10% 11% Figure D-53. Estimated 56-day LBR strength vs. cement content at fixed air content (7% through 11%) and fixed 20% fly ash mineral admixture 0.00 50.00 100.00 150.00 200.00 250.00 024681012 w/c ratioStrength, LBR 7% 8% 9% 10% 11% Figure D-54. Estimated 56-day LBR strength vs. w/c ratio at fixed air content (7% through 11%) and fixed 20% fl y ash mineral admixture

PAGE 261

243 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 050100150200250 Cement content, lbs/yd3Strength, psi 7% 8% 9% 10% 11% Figure D-55. Estimated 56-day compressive strength vs. cement content at fixed air content (7% through 11%) and fixe d 20% fly ash mineral admixture 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 024681012 w/c ratioStrength, psi 7% 8% 9% 10% 11% Figure D-56. Estimated 56-day compressive st rength vs. w/c ratio at fixed air content (7% through 11%) and fixed 20% fly ash mineral admixture

PAGE 262

244 0.00 50.00 100.00 150.00 200.00 250.00 050100150200250 Cement content, lbs/yd3Strength, LBR 12% 13% 14% 15% Figure D-57. Estimated 56-day LBR strength vs. cement content at fixed air content (12% through 15%) and fixed 20% fly ash mineral admixture 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 180.00 200.00 024681012 w/c ratioStrength, LBR 12% 13% 14% 15% Figure D-58. Estimated 56-day LBR strength vs. w/c ratio at fixed air content (12% through 15%) and fixed 20% fl y ash mineral admixture

PAGE 263

245 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 050100150200250 Cement content, lbs/yd3Strength, psi 12% 13% 14% 15% Figure D-59. Estimated 56-day compressive strength vs. cement content at fixed air content (12% through 15%) and fixe d 20% fly ash mineral admixture 0.00 20.00 40.00 60.00 80.00 100.00 120.00 024681012 w/c ratioStrength, psi 12% 13% 14% 15% Figure D-60. Estimated 56-day compressive st rength vs. w/c ratio at fixed air content (12% through 15%) and fixed 20% fly ash mineral admixture

PAGE 264

246 0.00 50.00 100.00 150.00 200.00 250.00 300.00 350.00 050100150200250 Cement content, lbs/yd3Strength, LBR 2% 3% 4% 5% 6% Figure D-61. Estimated 56-day LBR strength vs. cement content at fixed air content (2% through 6%) and fixed 50% ground granul ated blast-furnace slag mineral admixture 0.00 50.00 100.00 150.00 200.00 250.00 300.00 350.00 024681012 w/c ratioStrength, LBR 2% 3% 4% 5% 6% Figure D-62. Estimated 56-day LBR strength vs. w/c ratio at fixed air content (2% through 6%) and fixed 50% ground granul ated blast-furnace slag mineral admixture

PAGE 265

247 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 050100150200250 Cement content, lbs/yd3Strength, psi 2% 3% 4% 5% 6% Figure D-63. Estimated 56-day compressive strength vs. cement content at fixed air content (2% through 6%) and fixed 50% ground granulated blast-furnace slag mineral admixture 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 024681012 w/c ratioStrength, psi 2% 3% 4% 5% 6% Figure D-64. Estimated 56-day compressive st rength vs. w/c ratio at fixed air content (2% through 6%) and fixed 50% grou nd granulated blast-furnace slag mineral admixture

PAGE 266

248 0.00 50.00 100.00 150.00 200.00 250.00 300.00 050100150200250 Cement content, lbs/yd3Strength, LBR 7% 8% 9% 10% 11% Figure D-65. Estimated 56-day LBR strength vs. cement content at fixed air content (7% through 11%) and fixed 50% ground gra nulated blast-furnace slag mineral admixture 0.00 50.00 100.00 150.00 200.00 250.00 300.00 024681012 w/c ratioStrength, LBR 7% 8% 9% 10% 11% Figure D-66. Estimated 56-day LBR strength vs. w/c ratio at fixed air content (7% through 11%) and fixed 50% ground gra nulated blast-furnace slag mineral admixture

PAGE 267

249 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 050100150200250 Cement content, lbs/yd3Strength, psi 7% 8% 9% 10% 11% Figure D-67. Estimated 56-day compressive strength vs. cement content at fixed air content (7% through 11%) and fixed 50% ground granulated blast-furnace slag mineral admixture 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 024681012 w/c ratioStrength, psi 7% 8% 9% 10% 11% Figure D-68. Estimated 56-day compressive st rength vs. w/c ratio at fixed air content (7% through 11%) and fixed 50% ground granulated blast-furnace slag mineral admixture

PAGE 268

250 0.00 50.00 100.00 150.00 200.00 250.00 300.00 050100150200250 Cement content, lbs/yd3Strength, LBR 12% 13% 14% 15% Figure D-69. Estimated 56-day LBR strength vs. cement content at fixed air content (12% through 15%) and fixed 50% gr ound granulated blast-furnace slag mineral admixture 0 50 100 150 200 250 024681012 w/c ratioStrength, LBR 12% 13% 14% 15% Figure D-70. Estimated 56-day LBR strength vs. w/c ratio at fixed air content (12% through 15%) and fixed 50% ground gra nulated blast-furnace slag mineral admixture

PAGE 269

251 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 050100150200250 Cement content, lbs/yd3Strength, psi 12% 13% 14% 15% Figure D-71. Estimated 56-day compressive strength vs. cement content at fixed air content (12% through 15%) and fixed 50% ground granulated blast-furnace slag mineral admixture 0 20 40 60 80 100 120 140 024681012 w/c ratioStrength, psi 12% 13% 14% 15% Figure D-72. Estimated 56-day compressive st rength vs. w/c ratio at fixed air content (12% through 15%) and fixed 50% gr ound granulated blast-furnace slag mineral admixture

PAGE 270

252 LIST OF REFERENCES 1. Jawed, I., and Skalny, J., Hardened Mo rtar and Concrete with Fly Ash, Fly Ash in Concrete K. Wesche, ed., E&FN Spon, Great Britain, 1991. 2. Popovic, S., Concrete Making Materials Hemisphere Publishing Company, New York, NY, 1979. 3. Pons, F., Landwermeyer, J. S., and Kerns, L., Development of Engineering Properties for Regular and Quick-Set Flowable Fill, The Design and Application of Controlled Low-Strength Materials (Flowable Fill) ASTM STP 1331, A. K. Howard and J. L. Hitch, eds., American Society for Testing and Materials, West Conshohocken, PA, 1998. 4. Digioia, Jr., A. M., and Brenda, G. F., Fly Ash Design Manual for Road and Site Applications, Vol. 2: Slurried Placement EPRI Report Tr-100472, Electric and Power Research Institute, Palo Alto, CA, 1992. 5. Du, L., Folliard, K. J., and Trejo, D., Effects of Constituent Materials and Quantities on Water Demand and Compre ssive Strength of Controlled LowStrength Material, Journal of Materials in Civil Engineering, ASCE Publications, Reston, VA, November/ December 2002. 6. American Concrete Institute (AC I) Committee 229, ACI 229R-94 Report: Controlled Low Strength Materials (CLSM), Concrete International Vol. 16, No. 7, Farmington Hills, MI, July, 1994, p. 55-64. 7. Grandham, S., Seals, R. K. and Fox worthy, P. T., Phosphogypsum as a component of flowable fill, Transp ortation Research Record, No. 1546, 1996. 8. Florida Concrete and Products Association, Inc., Flowable Fill Demonstration RMC 2000, Orlando, FL, 2003. 9. Naik, T. R., Kraus, R. N., Sturzl, R. F ., and Ramme, B. W., Design and Testing Controlled Low-Strength Materials (CLSM) Using Clean Coal Ash, The Design and Application of Controlled LowStrength Materials (Flowable Fill) ASTM STP 1331, A. K. Howard and J. L. Hitch, ed s., American Society for Testing and Materials, West Conshohocken, PA, 1998.

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253 10. Webb, M. C., McGrath, T. J., and Selig, E. T., Field Test of Buried Pipe with CLSM Backfill, The Design and Application of Controlled Low-Strength Materials (Flowable Fill) ASTM STP 1331, A. K. Howard and J. L. Hitch, eds., American Society for Testing and Materials, West Conshohocken, PA, 1998. 11. Howard, A. K., Proposed Standard Pract ice for Installing Buried Pipe Using Flowable Fill, The Design and Application of Cont rolled Low-Strength Materials (Flowable Fill) ASTM STP 1331, A. K. Howard a nd J. L. Hitch, eds., American Society for Testing and Materi als, West Conshohocken, PA, 1998. 12. Riggs, E. H., and Keck, R. H., Specificat ions and Use of Controlled Low-Strength Material by State Tran sportation Agencies, The Design and Application of Controlled Low-Strength Materials (Flowable Fill) ASTM STP 1331, A. K. Howard and J. L. Hitch, eds., American Society for Testing and Materials, West Conshohocken, PA, 1998. 13. Baker, T. H. W., Frost Penetration in Fl owable Fill Used in Pipe Trench Backfill, The Design and Application of Controlled Low-Strength Materials (Flowable Fill) ASTM STP 1331, A. K. Howard and J. L. Hitch, eds., American Society for Testing and Materials, West Conshohocken, PA, 1998. 14. Hitch, J. L., Test Methods for Controlled Low-Strength Material (CLSM): Past, Present, and Future, The Design and Application of Controlled Low-Strength Materials (Flowable Fill) ASTM STP 1331, A. K. Howard and J. L. Hitch, eds., American Society for Testing and Materials, West Conshohocken, PA, 1998. 15. American Association of State Highway and Transportation Of ficials (AASHTO), Standard Specifications for Transportati on Materials and Methods of Sampling and Testing, Seventeenth Edition, Part 1 Specifications Washington, D.C., 1995. 16. Florida Department of Transportation (F DOT), Standard Specifications for Road and Bridge Construction, Flowable Fill Specifications Section 121, FDOT Map and Publication Sales, Tallahassee, FL, 2000. 17. Kendall, K., Interparticle Friction in Slurries, Tribology in Particulate Technology B. J. Briscoe and M. J. Adams Hilger, ed., Bristol, England, 1987. 18. Popovic, S., Fundamentals of Portland Ceme nt Concrete: A Quantitative Approach, Vol. 1: Fresh Concrete John Wiley & Sons, New York, NY, 1982. 19. Soroka, I., Portland Cement Paste and Concrete Chemical Publishing Co., Inc., New York, NY, 1979. 20. Rixom, M. R., and Mailvaganam, N. P, Chemical Admixtures for Concrete E&FN Spon, Great Britain, 1986. 21. Neville, A. M., Properties of Concrete, 4th edition John Wiley and Sons, Inc., New York, NY, 1998.

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254 22. Diamond, S., Cement Paste Micr ostructure in Concrete, Materials Research Society Proceedings Materials Research Society, Warrendale, PA, Vol. 85, 1987. 23. Helmuth, R., Fly Ash in Cement and Concrete Portland Cement Association, Skokie, IL, 1987. 24. Halverson, R.R., B. Boggs, J. Enyart and G. Madden., Accelerated nonpozzolanic reactions of high volume coal fl y ash concrete. Proceedings of the 14th International Symposium on Management and Use of Coal Combustion Products. Provided courtesy of the American Coal Ash Association: Alexandria, VA., 2001 25. Ledesma, R. and L.L. Isaacs., Thermal properties of coal ashes, Fly Ash and Coal Conversion By-Products: Characte rization, Utilization and Disposal VI. Robert L. Day and Fredrik Pl. Glasser, eds., Materials Research Society: Pittsburgh, Pennsylvania., 1990 26. Turner-Fairbank Highway Research Center (TFHRC)., User Guidelines for Waste and Byproduct Materials in Pavement Construction. (June 02, 2004). 27. McCarthy, G.J., J.K. Solem, O.E. Manz, a nd D.J. Hassett., Use of a database of chemical, mineralogical, and physical pr operties of North American fly ash to study the nature of fly ash and its utilizati on as a mineral admixture in concrete. Fly Ash and Coal Conversion By-Produc ts: Characterization, Utilization and Disposal VI. Robert L. Day and Fredrik Pl. Glasser, eds., Materials Research Society: Pittsburgh, Pennsylvania., 1990 28. Joshi, R. C., and Lohtia, R. P., Fly Ash in Concrete: Production, Properties and Uses, Vol. 2: Advances in Concrete Technology Gordon and Breach Science Publishers, Ontario, Canada, 1997. 29. Popovic, S., Fundamentals of Portland Cement Concrete: A Quantitative Approach, Vol. 1: Fresh Concrete John Wiley & Sons., Hoboken, NJ., 1982 30. Swanekamp, R., Disposal and reuse of coal combustion byproducts, Power Magazine 146, Houston, Texas, July 2002, p.37-41. 31. Boral Material Technologi es, Boral Class F Fly Ash, Product Brochure. San Antonio, TX., 2000 32. Stewart, B.R., Coal combustion product (CCP) production and use. Biogeochemistry of Trace Elements in Coal and Coal Combustion Byproducts Kenneth S. Sajwan, Ashok K. Alva, a nd Robert F. Keefer, eds. Kluwer Academic/Plenum Publishers: New York, NY., 1999 33. ACI Committee 233R, Ground Granulated Bl ast-Furnace Slag as a Cementitious Constituent in Concrete, American Conc rete Institute, Farmington Hills, Mich., 1995.

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255 34. Roy, D. M., and Idorn, G. M.,Hydrati on, Structure, and Properties of Blast Furnace Slag Cements, Mortars, and Concrete, ACI Journal, Proceedings V. 79, No. 6, Nov-Dec. 1982, pp. 445-457. 35. Mindess, S., and Young, J. F, Concrete Prentice-Hall Inc., Englewood Cliffs, NJ, 1981. 36. Hamilton County and the City of Cinci nnati, A Performance Specification for Controlled Low Strength Material, Cont rolled Density Fills (CLSM-CDF), Report, Cincinnati, OH, 1996. 37. Bhat, S. T, Use of Coal Combustion Residues and Foundry Sands in Flowable Fill, Ph.D. Dissertation, Purdue Un iversity, West Lafayette, IN, 1996. 38. Folliard, K. J., Trejo, D., Sabol, S. A., and Du., L., Controlled Low-Strength Material for Backfill, Utility Bedding, Void Fill and Bridge Approaches, Phase I Interim Report 24-12 National Cooperative Highway Research Program (NCHRP), 1999. 39. Najafi, F. T., and Tia, M., Use of Accelerated Flowable Fill in Pavement Section Florida Department of Trans portation, Tallahassee, FL, 2004. 40. Montgomery, D. C., Design and Analysis of Experiments, 5th edition John Wiley and Sons, Inc., New York, NY, 2001. 41. Oehlert, G. W., A First Course in Design and Analysis of Experiments, W. H. Freeman and Company, New York, NY, 2000. 42. Florida Department of Transportation (FDOT), Lime Rock Bearing Ratio Technician Certification Study Guide, 1986 Edition Tallahassee, FL, 1986. 43. Lucht, D.A., Thermal Performance of Flow able Fill Mixtures for Horizontal GSHP Systems, M.S. Thesis, Sout h Dakota State University, 1995. 44. Kosmatka, S. H., and Panarese, W. C., Design and Control of Concrete Mixtures 13th edition Portland Cement Association, Skokie, IL, 1994. 45. Bhat, S. T., and Lovell, C. W., Design of Flowable Fill: Waste Foundry Sand as a Fine Aggregate, Transportation Research Record 1546 Transportation Research Board, National Research Counc il, Washington, D.C., 1996. 46. Lerch, W., Basic Principles of AirEntrained Concrete, Portland Cement Association Special Report, Skokie, IL, 1960. 47. Natrella, M. G., Experimental Statistics, NBS Handbook 91 National Bureau of Standards, Washington, D.C., 1963.

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256 48. Draper, N. R., and Smith, H., Applied Regression Analysis 2nd edition John Wiley and Sons, Inc., New York, NY, 1981. 49. Willis, M. H., Early Assessment of Concrete Quality by Accelerating Compressive Strength Development with Heat (Results of ASTM Cooperative Test Program), Journal of Testing and Evaluation West Conshohocken, PA, Vol. 3, No. 4, July 1975. 50. Carino, N. J., Prediction of Potential Strength at Later Ages, Chapter 15, Significance of Tests and Properties of Concrete and Concrete Making Materials P. Klieger and J. F. Lamond, eds., ASTM STP 169C, West Conshohocken, PA, 1994. 51. Miller, R. G., Simultaneous Statistical Inference 2nd edition Springer-Verlag, New York, NY, 1981. 52. American Concrete Institute, Recommende d Practice for Evaluation of Strength Test Results of Concrete, ACI 21477 (97), Reported by ACI Committee 214, Farmington Hills, MI, 1997.

PAGE 275

257 BIOGRAPHICAL SKETCH Webert Lovencin was born on Monday, December 25, 1972, in Hatte Cheveux, Haiti, to Ms. Elvira Lovencin and Mr. Nicholas J. Pierre. In July 1982, he moved to the United States and attended Edison Park El ementary School, Edison Middle School, and Edison Senior High School in Miami, Florida. He graduated from Miami Edison Senior High School in June 1991. After graduating fr om high school he attended the University of Florida (UF). At UF, he earned a Bachelor of Science de gree in Civil Engineering in May 1997. He also received a Master of Engineering degree in August 1999 specializing in the area of transportation engineering. His research for this degree was titled An Investigation of Red Light Running in the City of Gainesville, Florida. Thereafter, he enrolled in a Doctor of Philosophy (Ph.D.) program specializing in public works/construction management and materials in the De partment of Civil a nd Coastal Engineering at UF. After a one-year stint of working on his P h.D. full time, Mr. Lovencin obtained a position with the Florida Department of Tran sportation (District 2) as a Professional Engineer Trainee. This two-year program consisted of various phases to provide experience in the many areas of the transportation field. After completing this program, he entered into the Senior Engineer Trai nee Program which consisted of specialized training in the area of construction mana gement. While working for the Florida Department of Transportation, he continued to pursue his graduate studies until he was

PAGE 276

258 awarded an Educational Leave with Pay by th e Department to continue his studies fulltime. Mr. Lovencin was married on July 15, 2000, to the former April Adrienne Raines. After completing his Ph.D., Webert Lovencin pl ans to continue to work for the Florida Department of Transportation.


Permanent Link: http://ufdc.ufl.edu/UFE0016580/00001

Material Information

Title: Assessment and Design of Properties for Flowable Fill Usage in Highway Pavement Construction for Conditions in Florida
Physical Description: Mixed Material
Copyright Date: 2008

Record Information

Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
System ID: UFE0016580:00001

Permanent Link: http://ufdc.ufl.edu/UFE0016580/00001

Material Information

Title: Assessment and Design of Properties for Flowable Fill Usage in Highway Pavement Construction for Conditions in Florida
Physical Description: Mixed Material
Copyright Date: 2008

Record Information

Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
System ID: UFE0016580:00001


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ASSESSMENT OF DESIGN AND PROPERTIES FOR FLOWABLE FILL
USAGE IN HIGHWAY PAVEMENT CONSTRUCTION
FOR CONDITIONS IN FLORIDA
















By

WEBERT LOVENCIN


A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY

UNIVERSITY OF FLORIDA


2007

































Copyright 2007

by

Webert Lovencin
































I would like to dedicate this dissertation to my parents, my lovely wife,
April Adrienne Raines-Lovencin, my sister, Natacha Egland,
my nieces and nephews, and to the tax payers who help fund
the public education systems in the state of Florida.














ACKNOWLEDGMENTS

I would like to acknowledge those individuals who were involved in the advance-

ment of this research and throughout my studies. First, I would like to express my most

sincere gratitude to Dr. Fazil T. Najafi, my advisor and supervisory committee chairman.

Dr. Najafi has been a mentor, a friend, and a continuous source of encouragement both

professionally and personally. I thank Dr. Mang Tia, the cochair of my committee, for

his valuable advice and suggestions throughout the research study and dissertation.

I would also like to thank the other members of my committee, Dr. Walter E.

Dukes, Dr. David J. Horhota, Mr. Timothy J. Ruelke, and Mr. Michael J. Bergin, for their

continued support, constructive comments, and recommendations during my tenure at the

University of Florida.

Many debts of gratitude go out to the folks at the Florida Department of Transpor-

tation State Materials Office (Physical Lab and Geotechnical Divisions) and District 2 -

Materials Office in Lake City, who assisted me with this research study. These

individuals include Richard Delorenzo, Craig Roberts, Terry Thomas, Tim Blanton, Mike

Davis, Glenn Johnson, Ben Watson, Willie Henderson, Chris Falade, Bobby Ivory, Scott

Clayton, and Daniel Langley.

I would also like to express my gratitude to Drs. Claude Villiers and Jonathan F.

Earle, and Mrs. Margie Williams for their continuous encouragement and support, as well

as Mrs. Candace J. Leggett for her immense patience and efficient editorial assistance

with writing this dissertation.









Finally, I want to specially thank my savior, God (Jehovah), my family in the

United States and abroad from where they have always conferred me their support and

for believing in me the way they do. But above all, I want to deeply thank my beloved

wife, April, for her immense love, indispensable help and patience. April has been the

sole person responsible for my achieving this goal. She has been the wall containing my

worry, my best critic, and my greatest supporter.
















TABLE OF CONTENTS



A C K N O W L E D G M E N T S ................................................................................................. iv

L IST O F T A B L E S .. ............ ................................................... ............... x...... .... ..x

LIST OF FIGURES ............................. .. .......... .................................. xii

ABSTRACT ..................................................................... xvii

CHAPTER

1 IN TR O D U C T IO N ........ .. ......................................... ..........................................1.

1.1 B background ............................................................................................................1
1.2 Problem Statem ent ..............................................................................................2
1.2 .1 S tren g th ................................................... ......................................... . .2
1.2.2 Shrinkage ...... ....................... ........ ....... .......... ... ..
1.3 H y p oth esis ..................................................... ............................................ . 5
1.4 O bjectiv es ...................................................... ............................................ . .6
1.5 Scope ................................................................. 6
1.6 Im portance of R research ......................................................................................6
1.7 R research A approach .............................................................................................7
1.8 O utline of the D issertation ..................................................................................9

2 LITER A TU RE REV IEW ........................................................................................10

2 .1 In tro d u ctio n ..........................................................................................................1 0
2.2 Flow able Fill Technology ..............................................................................10
2.2.1 Introduction ............................................................................................10
2.2.2 Types of Flow able Fill ............................................................................11
2.2.3 Advantages of Using Controlled Low Strength Material (CLSM)...........11
2.2.4 Engineering Characteristics of CLSM ............... .............. ..................... 13
2.2.5 U ses of Flow able Fill..............................................................................13
2.2.6 Delivery and Placement of Flowable Fill ...............................................14
2.2.7 L im its .........................................................................................................15
2.3 Specifications, Test M ethods, and Practices.....................................................15
2 .3 .1 In tro d u ctio n .................................... ...........................................................1 5
2.3.2 A STM Standard Test M ethods ..................................................................17









2.3.2.1 Standard Test Method for Preparation and Testing of
CLSM Test Cylinders (ASTM D 4832-02) ..... ................17
2.3.2.2 Standard Practice for Sampling Freshly Mixed CLSM
(A ST M D 597 1-96) ....................... ...1... ..8.. ........ .. .... .. .. .. ................ 18
2.3.2.3 Standard Test Method for Unit Weight, Yield, Cement Content
and Air Content (Gravimetric) of CLSM (ASTM D 6023-96) ................18
2.3.2.4 Standard Test Method for Ball Drop on CLSM to Determine
Suitability for Load Application (ASTM D 6024-96).............................. 19
2.3.2.5 Standard Test Method for Flow Consistency of CLSM
(ASTM D 6103-96) ........ .............................20
2.3.3 Other Currently Used and Proposed Test Methods...............................20
2.3.4 Specifications by the State Departments of Transportation ...................22
2.3.5 Use of Flowable Fill in the State of Florida ......................... ................ 24
2.3.5.1 M material Specifications (Section 121-2)..................... ................ 24
2.3.5.2 Construction Requirements and Acceptance (Section
121-5, 121-6) ................................ .. .. ... ................... 25
2.3.5.3 Guideline for Construction Requirements and Acceptance
(Section 121-5, 121-6) .......................................... ........... .. ............. 25
2.4 Early Set and Strength D evelopm ent.............................................. ................ 26
2.4.1 Introduction ......................................................................................... 26
2 .4 .2 B eh av ior of Slu rries................................................................. ............... 2 6
2.4.3 Early Hydration of Cem ent Particles.................................... ................ 27
2.4.4 Influence of Water to the Hydration of Cement...................................28
2.4.5 Effects of Set Accelerator on Hydration of Cement...............................29
2 .4 .6 Set T im e............................... .............................................................. 29
2.4.7 Strength D evelopm ent ....................................................... ................... 30
2.4.8 Use of Mineral Admixture (Fly Ash and Granulated Ground Blast
Furnace Slag) in Flow able Fill.................................................... ................ 31
2 .4 .8.1 F ly ash .................................................................................... 3 1
2 .4 .8 .2 S la g ....................................................................... .. ........... ... ............ 3 4
2.4.8.3 Difference between fly ash and slag........................... ................ 36
2.4.8.4 Specific applications .............. .. ... ................ 36
2.4.8.5 Mixture proportioning/mixture compliance...............................36
2.4.9 Effect of M oisture on Strength............................................. ................ 37
2.5 Strength Prediction M models ......................................................... 38
2.5.1 Introduction .............. ..... ............. ............... 38
2.5.2 Hamilton County-Removability Index ................................ ................ 38
2 .5.3 B hat's Study ...................................................................................... 39
2.5.4 N CH R P-Study ................. .............................................................. 40
2.6 FD O T/U F Flow able Fill Study ....................................................... ................ 42

3 MATERIALS AND LABORATORY EXPERIMENTAL PROGRAM ...................44

3 .1 In tro d u ctio n ....................................................................... ................................... 4 4
3.2 Experim ental D esign ....................................... .... ................ 44
3.2.1 Rationale for Selecting Mixture Parameters.........................................44
3.2.2 M ixture Proportioning .......................................................... ................ 46









3.2.3 Specimen Sample Collection per Batch Mix........................................49
3.2.4 Specimen Molds ........................ ......... ..... .......... .....49
3.2.5 Fabrication of Flowable Fill Specimens ..............................................50
3.2.5.1 Preparation of m olds .................................................. ................ 50
3.2.5.2 M ixing of flow able fill ............................................... ................ 50
3.2.5.3 C asting of flow able fill............................................... ................ 53
3.3 Limerock Bearing Ratio Test (Florida Test Method 5-515)...............................55
3.4 C om pressive Strength T est............................................................. ................ 60
3.5 Proctor Penetrom eter Test ........................................................ 64
3.6 D trying Oven .................... ... ........ ............................................. 65
3.7 Drying Shrinkage of Flowable Fill Mixtures..................................................65
3 .7 .1 M eth o d 1 .................................................................................................... 6 6
3 .7 .2 M eth o d 2 .................................................................................................... 6 9
3 .7 .3 M eth o d 3 .................................................................................................... 7 0
3 .8 M materials .............................................................................................................. 7 1
3 .8 .1 C e m e n t....................................................................................................... 7 1
3 .8 .2 F ly A sh ...................................................................................................... 7 2
3.8.3 B last Furnace Slag ..................................... .. ........ .......... .. .. ........ ..... 72
3 .8 .4 A ggreg ates ........................................................ .................... . ........... 73
3.8.4.1 A ggregate gradation ................................................... ................ 74
3.8.4.2 Physical properties, absorption and moisture content..................76
3.8.4.3 Storage of fine aggregates ............... ................................... 77
3.8.5 A dm ixtures ........................................................................................ 78
3 .8 .6 W after ......................................................................................................... 7 8

4 LABORATORY RESULTS AND DISCUSSIONS .............................................79

4 .1 In tro d u ctio n ....................................................................... ................................... 7 9
4.2 Laboratory R results ............................................................. ............ ................... 79
4.2.1 Lim erock B hearing R atio (LBR)............................................ ................ 79
4.2.2 C om pressive Strength (psi) .................................................. ................ 79
4.2.3 V olum e Change .................................................. .............. .... .................. .. 84
4.2.4 Proctor Penetrometer Setting Strength (psi).........................................85
4.2.5 Strength Gained Between 28 and 56 Days...........................................91
4.2.6 LBR Oven Sam ple Results.................................................... 92
4.3 F actors A affecting Strength.............................................................. ................ 96
4.3.1 W ater-to-Cem ent (w /c) R atio ............................................... ............... 96
4.3.2 C em ent C ontent .............................................. ...... ........ .. .. .. ........ .... 98
4.3.3 Effect of Air Content on Strength ........................ ........ .................... 100
4.3.4 Effect of Mineral Admixtures (Fly Ash and Blast Furnace Slag) on
Strength .................. .. .. ..... ............. ................................. 101
4.4 Comparison of Mix Using Type I/II Cement vs. Type I Cement................... 102
4.5 Drying Shrinkage (Volume Change)............... .........................105
4.6 Interpretation of Plastic Test Results........................................ 108





viii









5 STA TISTIC A L A N A L Y SIS ...................................... ........................................ 111

5 .1 In tro d u ctio n ....................................................................................................... 1 1 1
5.2 Statistical M odel D erivation ............................................................................ 111
5.3 A accelerating Strength Testing ....... ......... ........ .....................1... 18
5.3.1 B background ................................................................................. 118
5.3.2 A accelerated C during ....................................................... ............... 119
5.3.3 A nalysis...................................................................................................119
5.3.4 Confidence Band for Regression Line ....... ................. ................... 124
5.3.5 Estimate of Later Strength............... ... ......................... 124
5.3.6 Analysis on Other Samples ....... ... ....................... 125
5.4 Model Validation and Evaluation of Accuracy ...................... ...................128
5.4.1 Varying Strength Prediction Models for Trend..................................128
5.4.2 Comparison of Strength Prediction Models ................. ...................145
5.4.3 Mixture Design Examples to Validate Models ..................................150
5.5 Summary of Model Equations and Limitations...................... ...................157

6 SUMMARY, CONCLUSIONS AND RECOMMENDATIONS ......................... 164

6 .1 S u m m a ry ............................................................................................................ 1 6 4
6 .2 C o n clu sio n s........................................................................................................ 16 6
6.3 R ecom m endations ................................................................... ............... 167

APPENDIX

A FLOWABLE FILL STUDY BATCH MIX DESIGN MATRIX .............................169

B LBR AND COMPRESSIVE STRENGTH DATA OBTAINED IN THE
LABORATORY ..................................... .............................185

C ANALYSIS OF VARIANCE (ANOVA), PARAMETERS, AND
STANDARD ERROR FOR MODELS .......... .........................200

D ESTIMATED 28- AND 56-DAY STRENGTH...... ......................................215

LIST O F R EFEREN CE S ... ................................................................... ................ 252

BIOGRAPH ICAL SKETCH .................. .............................................................. 257















LIST OF TABLES


Table page

2-1. Current ASTM standards on controlled low strength material (CLSM)................... 16

2-2. States surveyed and their specification on flowable fill.......................................22

2-3. Specified acceptance strengths and ages .............................................. ................ 23

2-4. Suggested m ixture proportions, lb/yd3 ................................................ ................ 23

2-5. FDOT materials specification requirements.........................................................24

2-6. FD O T flow able fill m ix design ............................................................ ................ 25

2-7. R em ovability m odulus (R E) ....................................... ....................... ............... 39

3-1. Mixture parameters .................................. ......... ...... ............... 45

3-2. Summary of sample specimens collected per mix................................................49

3-3. Properties of fresh flowable fill (Experiment 1)...................................................56

3-4. Properties of fresh flowable fill (Experiment 2)...................................................57

3-5. Specifications for LBR test equipment.....................................................59

3-6. Chemical composition of cement used.....................................................71

3-7. Physical characteristics of cem ent........................................................ ................ 72

3-8. Chem ical and physical analyses of fly ash........................................... ................ 73

3-9. Chemical and physical analyses of blast furnace slag..........................................73

3-10. Fine aggregate location source ........................................................... ................ 74

3-11. ASTM C33-02A and FDOT specifications for fine aggregate gradation ...............75

3-12. Physical properties of fine aggregates (silica sand)............................................76

4-1. LBR strength results for Experim ent #1 ............................................... ................ 80









4-2. LBR strength results for Experim ent #2............................................... ............... 81

4-3. Compressive strength results for Experiment #1.................................. ................ 82

4-4. Compressive strength results for Experiment #2.................................. ................ 83

4-5. V olum e change results for Experim ent #1 .............................................. ................ 86

4-6. Volum e change results for Experim ent #2 ........................................... ............... 87

4-7. Mix proportions and proctor penetrometer results for Experiment #1 ......................88

4-9. Two-day oven LBR strength results for Experiment #1 ................. ..................... 93

4-10. Two-day oven LBR strength results for Experiment #2.................................... 94

4-11. Comparison of mixture components and their influence on accelerated
2-day oven and 28-day LBR strength ................................................. ................ 95

4-12. Comparison of mixture components and their influence on percent
v olu m e ch an g e ........................................................................................................ 10 6

5-1. Standard error of regression coefficients for equations relating mixture
constituents to LBR, compressive strength and percent volume change .............116

5-2. Estimation of confidence interval for 28-day strength................. ...................122

5-3. Summary of regression equations for accelerated (oven) 28-day
and 56-day LBR strength .................. ......................................................... 127

5-4. NCHRP's CLSM mixture proportions and fresh properties [38]............. 146

5-5. Comparison of the NCHRP measured and predicted 28-day strength
for air-entrained mixtures strength prediction model.................. ...................147

5-6. Comparison of estimated 28-day compressive strength................ ...................149

5-7. Summary of materials required for validation mixtures................ ...................154

5-8. Summary of plastic properties of validation mixture models............................... 155

5-9. Comparison of estimated and experimental results for
batch m ixes lv through 6v .................. ....................................................... 158

5-10. Comparison of estimated and experimental results for
batch m ixes 7v through 1 lv ........................................................ 159

5-11. Summary of recommended strength prediction equations listed
w ith variables and range...................................... ........................ ............... 162
















LIST OF FIGURES


Figure page

1-1. Laboratory task process .................................................................. 8

2-1. Influence of water/cement (w/c) ratio on the setting of Portland cement paste ........28

2-2. Bhat's strength prediction m odel.................. .................................................... 40

3-1. C concrete m ixer used in study ...................................... ...................... ................ 51

3-2. Pressure m eter test for air content ........................................................ ................ 52

3-3. Cast flow able fill in LBR sam ples.................. .................................................. 53

3-4. Cast flowable fill in 4-in. x 8-in. compressivee strength) samples.........................54

3-5. Cast flowable fill in 6-in. x 12-in. (volume change) samples ...............................54

3-6. Cross section of seated LBR penetration piston [30] ...........................................58

3 -7 L B R m ach in e ............................................................................................................. 5 9

3-8. Graph example showing typical load penetration curve that
requires no correction ........................................................................ 61

3-9. Graph example showing correction of typical load penetration
curve for sm all surface irregularities................................................... ................ 62

3-10. Typical set-up for compressive strength test......................................................63

3-11. Typical proctor penetrom eter ............................................................. ................ 64

3-12. Test set-up for measuring shrinkage using LVDTs...........................................68

3-13. Schematic of test set-up for measuring shrinkage using LVDTs ......................... 68

3-14. Three-dial gauge reading m ethod ...................................................... ................ 69

3-15. D ial gauge shrinkage reading being taken.......................................... ................ 70

3-16. Gradation of fine aggregates-ASTM specs.......................................................... 75









3-17. Gradation of fine aggregates-FDOT specs ........................................ ................ 76

3-18. Storage and rem oval of fine aggregates ............................................. ................ 77

4-1. Load deformation responses for batch mix #4, at 3-, 28- and 56-day duration.........84

4-2. Percent increase in 56-day strength as compared to 28-day strength (LBR) ............91

4-3. Percent increase in 56-day strength as compared to 28-day strength (psi) ...............92

4-4. Relationship between 28-day bearing strength (LBR) and w/c ratio at 7.5%
d esig n air content ..................................................................................................... 9 6

4-5. Relationship between 28-day bearing strength (LBR) and
w /c ratio at 17.5% design air content.................................................. ................ 96

4-6. Relationship between 28-day compressive strength (psi) and
w /c ratio at 7.5% design air content.................................................... ................ 97

4-7. Relationship between 28-day compressive strength (psi) and
w /c ratio at 17.5% design air content.................................................. ................ 97

4-8. Relationship between 28-day bearing strength (LBR) and
cem ent content at 7.5% design air content.......................................... ................ 98

4-9. Relationship between 28-day bearing strength (LBR) and
cem ent content at 17.5% design air content........................................ ................ 98

4-10. Relationship between 28-day compressive strength (psi) and
cem ent content at 7.5% design air content.......................................... ................ 99

4-11. Relationship between 28-day compressive strength (psi) and
cem ent content at 17.5% design air content........................................ ................ 99

4-12. Relationship between 28-day LBR strength and cement content.........................99

4-13. Relationship between 28-day compressive strength (psi) and cement content .....100

4-14. Effect of mineral admixtures on 28-day LBR strength ............... ...................101

4-15. Effect of mineral admixtures on 56-day LBR strength ............... ...................102

4-16. Compressive strength (psi) of Type I/II vs. Type I cement for BM15................103

4-17. LBR strength of Type I/II vs. Type I cement for BM15 ..................................103

4-18. Compressive strength (psi) of Type I/II vs. Type I cement for BM 25...........103

4-19. LBR strength of Type I/II vs. Type I cement for BM 25 .............................104









4-20. Compressive strength (psi) of Type I/II vs. Type I cement for BM 48............... 104

4-21. LBR strength of Type I/II vs. Type I cement for BM 48 .............................104

4-22. Compressive strength (psi) of Type I/II vs. Type I cement for BM 54.............. 105

4-23. LBR strength of Type I/II vs. Type I cement for BM 54 ..................105

4-24. Effect of w/c ratio on volume change...... .... ........................ 107

4-25. Effect of cement content on volume change ....... ... ................................... 107

4-26. Effect of mineral admixtures on volume change...... .................. .................. 108

4-27. Flow diameter vs. sand-to-water ratio........... ... ........................................ 110

5-1. Residuals versus fitted values plot (28-day LBR)...... .................. ................... 116

5-2. Residuals versus fitted values plot (28-day psi)....... .................. ................... 117

5-3. Residuals versus fitted values plot (% volume change) ............... ...................117

5-4. Accelerated curing vs. 28-day normal curing strength................. ...................123

5-5. Accelerated curing vs. 28-day normal curing strength for all mixtures ................126

5-6. Accelerated curing vs. 56-day normal curing strength for all mixtures ................126

5-7. Estimated 28-day LBR strength vs. cement content at fixed air (15%)
and fixed 0% mineral admixture ....... ........ ........ ..................... 130

5-8. Estimated 56-day LBR strength vs. cement content at fixed air (15%)
and fixed 0% mineral admixture ....... ........ ........ ..................... 130

5-9. Estimated 28-day compressive strength vs. cement content at
fixed air (15%) and fixed 0% mineral admixture...... .................. ................... 131

5-10. Estimated 28-day compressive strength vs. cement content at
fixed air (15%) and fixed 0% mineral admixture...... .................. ................... 131

5-11. Estimated volume change vs. cement content at fixed air (15%) and
fixed 0% m mineral adm ixture........................................................ ............... 132

5-12. Estimated 28-day LBR strength vs. w/c ratio at fixed air (15%) and
fixed 0% m mineral adm ixture.................................. ...................... ............... 132

5-13. Estimated 56-day LBR strength vs. w/c ratio at fixed air (15%) and
fixed 0% m mineral adm ixture.................................. ...................... ............... 133









5-14. Estimated 28-day compressive strength vs. w/c ratio at fixed air (15%)
and fixed 0% mineral admixture ....... ....... ........ ..................... 133

5-15. Estimated 56-day compressive strength vs. w/c ratio at fixed air (15%)
and fixed 0% mineral admixture ....... ....... ........ ..................... 134

5-16. Estimated volume change vs. w/c ratio at fixed air (15%) and
fixed 0% m mineral adm ixture........................................................ ............... 134

5-17. Estimated 28-day LBR strength vs. cement content at fixed air (8%) and
fixed 20% fly ash mineral admixture ........................................ 135

5-18. Estimated 56-day LBR strength vs. cement content at fixed air (8%) and
fixed 20% fly ash mineral admixture ........................................ 135

5-19. Estimated 28-day compressive strength vs. cement content at
fixed air (8%) and fixed 20% fly ash mineral admixture..................................136

5-20. Estimated 56-day compressive strength vs. cement content at
fixed air (8%) and fixed 20% fly ash mineral admixture..................................136

5-21. Estimated volume change vs. cement content at fixed air (8%) and
fixed 20% fly ash mineral admixture ........................................ 137

5-22. Estimated 28-day LBR strength vs. w/c ratio at fixed air (8%) and
fixed 20% fly ash mineral admixture ........................................ 137

5-23. Estimated 56-day LBR strength vs. w/c ratio at fixed air (8%) and
fixed 20% fly ash mineral admixture ........................................ 138

5-24. Estimated 28-day compressive strength vs. w/c ratio at fixed air (8%)
and fixed 20% fly ash mineral admixture ....... ........ ....................................... 138

5-25. Estimated 56-day compressive strength vs. w/c ratio at fixed air (8%)
and fixed 20% fly ash mineral admixture ....... ........ ....................................... 139

5-26. Estimated volume change vs. w/c ratio at fixed air (8%) and
fixed 20% fly ash mineral admixture ........................................ 139

5-27. Estimated 28-day LBR strength vs. cement content at fixed air (10%)
and fixed 50% ground granulated blast-furnace slag mineral admixture.............140

5-28. Estimated 56-day LBR strength vs. cement content at fixed air (10%)
and fixed 50% ground granulated blast-furnace slag mineral admixture.............140

5-29. Estimated 28-day compressive strength vs. cement content at fixed air (10%)
and fixed 50% ground granulated blast-furnace slag mineral admixture.............141









5-30. Estimated 56-day compressive strength vs. cement content at fixed air (10%)
and fixed 50% ground granulated blast-furnace slag mineral admixture.............141

5-31. Estimated volume change vs. cement content at fixed air (10%) and
fixed 50% ground granulated blast-furnace slag mineral admixture .................142

5-32. Estimated 28-day LBR strength vs. w/c ratio at fixed air (10%) and
fixed 50% ground granulated blast-furnace slag mineral admixture .................142

5-33. Estimated 56-day LBR strength vs. w/c ratio at fixed air (10%) and
fixed 50% ground granulated blast-furnace slag mineral admixture .................143

5-34. Estimated 28-day compressive strength vs. w/c ratio at fixed air (10%) and
fixed 50% ground granulated blast-furnace slag mineral admixture .................143

5-35. Estimated 56-day compressive strength vs. w/c ratio at fixed air (10%) and
fixed 50% ground granulated blast-furnace slag mineral admixture .................144

5-36. Estimated volume change vs. w/c ratio at fixed air (10%) and fixed
50% ground granulated blast-furnace slag mineral admixture.............................144

5-37. Comparison of measured and predicted 28-days strength................................147

5-38. Comparison of estimated 28-day compressive strength for Bhat,
NCHRP, and dissertation models....... ...... ..... ..................... 150

5-39. Comparison of estimated 28-day compressive strength for NCHRP
and dissertation m odels .................. ............................................................ 150

5-40. Comparison of measured and predicted 28-day LBR strength of validation
m ixtures of m odel ... .. .................................. .......................................... 160

5-41. Comparison of measured and predicted 28-day compressive strength of
validation m fixtures of m odel....................................................... ............... 160

5-42. Comparison of measured and predicted 28-day (oven) LBR strength of
validation m fixtures of m odel....................................................... ............... 161















Abstract of Dissertation Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Doctor of Philosophy

ASSESSMENT OF DESIGN AND PROPERTIES FOR FLOWABLE FILL
USAGE IN HIGHWAY PAVEMENT CONSTRUCTION
FOR CONDITIONS IN FLORIDA

By

Webert Lovencin

May 2007

Chair: Fazil T. Najafi
Cochair: Mang Tia
Major Department: Civil and Coastal Engineering

Flowable fill, also known as controlled low-strength material (CLSM), is a self

compacting cementitious material primarily used as a backfill in lieu of compacted soil.

Flowable fill is an extremely versatile construction material that has been used in a wide

variety of applications. There are two types of flowable fill, excavatable and

nonexcavatable. An excavatable flowable fill mixture is considered excavatable when

the 28-day compressive strength is 100 psi. Nonexcavatable mixtures are mixes in which

the minimum design strength is at 125 psi or greater. The ability to control and predict

the strength and volume change (shrinkage) is an important aspect to consider when

designing a flowable fill mixture. Various studies have been conducted to better

understand and predict quality control measures such as the strength and the occurrence

of shrinkage in flowable fill.









The aim of this research was to vary components of excavatable flowable fill

mixtures. A 4 x 3 x 2 x 3 factorial design (i.e., 4 levels of cement, 3 levels of mineral

admixtures, 2 levels of air content, and 3 levels of water/cement ratio) was applied to

evaluate the compressive strength, limerock bearing ratio (LBR) strength, and shrinkage.

With this study's objective in mind, a total of 58 mixtures were selected from the

factorial design matrix and batched in a laboratory. The strength of the mixtures was

evaluated at 6 hours, 1 day, 2 days oven cured, 3 days, 28 days and 56 days.

Mathematical models were developed to predict the LBR, compressive strength,

and volume change. An accelerated curing method, along with prediction models, was

developed to help estimate long-term strength of flowable fill. Based on the performance

of the statistical analysis, it was found that the models developed from this study

provided good correlations for estimating strength and volume change of excavatable

flowable fill mixture. Though the models were found to provide good correlations, the

formula developed for estimating the volume change was found to be unacceptable for

design application. This study provides a rational method for engineers to utilize when

designing flowable fill mixture.


xviii














CHAPTER 1
INTRODUCTION

1.1 Background

The construction industry searches for the most cost and time efficient means for

completing its projects. Many of these projects include cutting and backfilling trenches

for structure and drainage pipe installation. Often cutting and backfilling trenches

disrupts major traffic arteries. Standard practice for backfilling trenches includes soil

being placed in 6-inch lifts and compacted until a minimum density threshold is achieved.

The soil tests required to set and verify the density threshold in the field require several

days to complete. To help in this matter, newer forms of construction material have been

introduced. The most common is called controlled low strength material (CLSM), also

known as flowable fill. The use of flowable fill negates the need for placing the 6-inch

lifts and eliminates the need for practically all tests, excluding a simple in-place soil test.

Flowable fill is an extremely versatile construction material that has been used in a

wide variety of applications. Among the many successful applications of flowable fill are

slurried backfill for walls, culverts, pipe trenches, bridge abutments and retaining walls;

backfill for abandoned underground structures (including mines) or tanks; and floating

slab foundation for lightweight structures [1,2]. Flowable fill offers a number of

advantages over conventional earthfill materials that require controlled compaction in

layers [2]. The advantages include ease of mixing and placement, the ability to flow into

hard-to-reach places, and the self-leveling characteristic of the fill.









1.2 Problem Statement

1.2.1 Strength

Flowable fill answers the need for a fill that allows prompt return to traffic flow,

does not settle, does not require vibration or other means of compaction, can be

excavated, is fast to place, and safer than other forms of fill. One requirement typically

encountered with flowable fill is the need to limit the maximum compressive strength [3].

This requirement is necessary in cases where future excavation may be required for

maintenance and repair of embedded utilities. To predict the long-term strength and the

excavatability of flowable fill using conventional excavating equipment, many

approaches are employed. One approach for predicting whether or not a flowable fill mix

is excavatable is to develop a correlation using its early age strength and long-term

strength. For example, a mixture exhibiting strength that is less than 100 psi would be

classified as being excavatable. Mixtures resulting in strengths higher than 100 psi would

be very difficult to excavate and would be termed nonexcavatable.

According to Digiola and Brenda [4], the proper control of strength in flowable fill

is an important criterion used to develop a mix design. Despite this known criterion, a

review of literature shows few studies published in proper control of strength in flowable

fill. In using flowable fill, not only is it required to meet minimal strengths to maintain

and provide suitable structural support, but the maximum strength development must also

be controlled to allow for future excavation. A study by Pons et al. [3] shows that in

1994, about 80% of the concrete producer market producing flowable fill carried the

understanding or expectation for excavatability. For these reasons, design strengths often

must be assigned a range of strengths from "minimally acceptable" to "maximum

allowable."









Many state agencies specify acceptance strengths at a curing age of 28 days, while

others include 56-day strength in their specifications [5]. In some cases, the maximum

strengths are listed to enable excavation for a later date. Some state agencies, however,

list the target strengths instead of maximum strengths which causes some concrete plants

to produce flowable fill mixes with minimum strength, as they would normally for

Portland cement concrete. In general, the desired strength is the maximum hardness that

can be excavated at a later date using conventional excavating equipment. The existing

Florida Department of Transportation (FDOT) flowable fill specification requires field

tests to verify that a minimum penetration resistance is achieved.

Flowable fill mixtures are usually designed on the basis of compressive strength

development. Little information is available in which the terminology used for

describing the strength of flowable fill is something other than compressive strength.

This method of describing the quality of flowable fill is conventional throughout the

ready mix industry. Because flowable fill is used as a backfill material similar to soil, a

suitable unit instead of compressive strength, such as limerock bearing ratio (LBR), is

needed to describe the in-place bearing strength of the flowable fill mixture. Making

such a change would alter the state-of-the-art for relating the quality of strength for

flowable fill mixtures.

1.2.2 Shrinkage

To understand why shrinkage occurs, one must first understand the materials in

flowable fill. Just as shrinkage occurs in concrete, it also occurs in flowable fill.

Cement, a key ingredient in flowable fill, when mixed with water forms a paste and a

chemical reaction called "hydration" occurs. The hardened cement paste is what binds all

the other ingredients together to create flowable fill.









During the process of hydration, tiny voids filled with water and air form in the

paste. The more porous the cement paste is in a mixture, the weaker the mixture. Studies

have shown that voids in concrete play a vital role in shrinkage. After pouring, concrete

will change volume as moisture levels change. In flowable fill this phenomenon also

takes place. Another condition playing a key role in concrete shrinkage is temperature.

Expansion and shrinkage due to changes in temperature can put stress on flowable fill,

resulting in cracks.

Studies have shown that high water/cement (w/c) ratio and high water content are

the two factors known to cause unwarranted drying-shrinkage in concrete. Although

flowable fill has a higher w/c ratio and higher water content than concrete, studies on

drying shrinkage have indicated that flowable fill exhibits shrinkage to a lesser extent

than concrete. Typical reports of linear-shrinkage values on flowable fill are in the range

of 0.002 to 0.05 percent (6). These values are similar to concrete with low drying

shrinkage. The shrinkage and expansion of flowable fill tend to continue varying

throughout testing. A study by Grandham et al. (7) found that the maximum shrinkage

and expansion values of flowable fill were generally less than the acceptable limit

established for concrete (7).

Since flowable fill is often placed underneath roadways as a road base, varying

volume change is an important attribute to investigate. In various parts of Florida

moisture is greatly abundant. Because this is so, when flowable fill is used in these areas,

it is affected, forcing the flowable fill volume to alter. From the volume change

activities, cracks are often created, leading to water seepage through the cracks causing









roadbed damage and deficiencies in the roadway. The final result may include pavement

depressions or pavement humps.

Various problems encountered while using flowable fill arise from the lack of

documented procedures to measure or determine long-term strength for future excava-

tion. Some areas that need further investigation and documentation are as follows:

* A practical method for designing flowable fill mixtures.

* A thorough investigation of the effects of shrinkage in flowable fill.

* A developed flowable fill design method that utilizes commonly used units for
describing the strength of backfill materials, such as limerock bearing ratio (LBR)
instead of compressive strength.

* A study identifying long-term performance of flowable fill, particularly how the
plastic properties of flowable fill affect its long-term strength and excavatability.

It is critical that research be conducted at this time given there is a large number of

roadway construction, maintenance, and rehabilitation projects taking place throughout

Florida.

1.3 Hypothesis

Several factors in flowable fill are found to be similar to those identified in concrete

as a controlled measure for predicting strength. The factors include w/c ratio, cement

content, fly ash content, and plastic properties. The following hypothetical questions

may be asked: (1) Is it possible to get target strength (100 LBR) for flowable fill if

quantities of its mixture components are known? (2) If so, can varying the components of

flowable fill mix help target strength and shrinkage?

Laboratory experiments can be conducted to identify key components to help lay a

foundation for developing rational methods to approach development of flowable fill

mixture design for construction. In addition, models can be developed to employ known









component parameters to produce reliable results for predicting strength and field

performance (i.e., shrinkage) of flowable fill.

1.4 Objectives

The primary objectives of this research are as follows:

* Vary mixture components of flowable fill, to help predict strength using prediction
models.

* Vary mixture components to predict shrinkage in flowable fill using a prediction
model.

* Develop mix design procedures utilizing fine aggregate materials commonly used
for flowable fill in the state of Florida.

* Identify setting behavior of flowable fill.

* Provide recommendations where warranted from findings.

1.5 Scope

This is a continuance of a preliminary study in which the key goal was to evaluate

the performance of flowable fill in pavement sections using accelerated and nonacceler-

ated mixtures. Using knowledge acquired from the findings of the preliminary study, the

scope of the current research will focus on developing strength prediction models that

incorporate flowable fill mix parameters. It is critical to vary known components (i.e., air

content, cementitious content, etc.) for establishing the framework and creating the

database to use for prediction models. Thus, this research will focus on the effects of the

following:

* strength in LBR for flowable fill mixtures; and
* change in flowable fill volume due to shrinkage.

1.6 Importance of Research

The proper control of strength development in flowable fill applications is an

important criterion in developing a design mixture. Very few studies have been









published evaluating the long-term strength of flowable fill in LBR. This research will

help to develop mix design procedures for concrete producers using flowable fill and will

benefit the construction industry.

The volume changes due to shrinkage are of considerable importance. If the

amount of volume change in flowable fill due to shrinkage is derivable, producers will be

able to modify their mixes for obtaining optimal mixtures. Also, contractors can

compensate as necessary.

1.7 Research Approach

To meet the research objectives, this study was conducted utilizing the process

categorized as tasks provided below.

* Task 1 Literature search:
Examine existing ideas, theories and results published about flowable fill
reviewing various properties affecting its mixtures
Review work done on concrete and geotechnical engineering practices
Review past and current flowable fill practices materials, design mixes,
properties, and testing practices to measure performance.

* Task 2 Data collection:
Prepare laboratory design mixtures
Design the experiment for laboratory mixtures
Use factorial design
Vary mixture components (i.e., cement, fly ash/slag, and
water/cement ratio)
Prepare mixture proportions and samples
Run small-scale design mixes obtained from the study's factorial design
Obtain test results from all design mixes performed.

* Task 3 Data analysis:
Analyze experimental results obtained from laboratory tests carefully to meet
the objectives of the study.

* Task 4 Model development using empirical approach:
Develop model using SAS and Minitab.

* Task 5 Model interpretation:
Evaluate reliability and effectiveness of models.











* Task 6 Final dissertation writing process:
After completing Tasks 1 through 5, prepare a final report in the form of a
dissertation to highlight the achievements and original contributions of the
research.

The flowchart presented in Figure 1-1 gives a schematic view of the laboratory task

process to be conducted as part of the research.


Assessing the design and properties for
controlled low strength materials (CLSM)
usage in highway pavement


Randomly select mixtures




Run batch mixtures


Make
modifications


Attain target air content
and plastic properties


Are the
No analyzed Yes
results viable Y


,, Determine
performance



Develop model and
framework


Figure 1-1. Laboratory task process









1.8 Outline of the Dissertation

This dissertation is comprised of six chapters. A brief summary of each chapter is

provided below.

Chapter 1 describes the background, problem statement, hypothesis, objectives,

scope, and importance of this research and the approach used to conduct the research.

Chapter 2 presents a literature review of basic information relating to flowable fill.

The review focuses on flowable fill technology, current practices, strength development,

and strength prediction models.

Chapter 3 explains information pertaining to the materials and experimental testing

program evaluated in the study. The method of preparation of the flowable fill mixtures,

design mix selection, mixture proportions, test specimens, testing procedure, testing

equipment and testing procedures utilized in this study are also presented.

Chapter 4 provides the laboratory results of the flowable fill mixtures. Detailed

discussions on the results are included, along with influencing strength factors affecting

the long-term behavior of flowable fill.

Chapter 5 discusses the results and statistical analysis performed on the laboratory

data. Models predicting strength and volume change are provided. An accelerated

strength testing method is presented for estimating the long-term strength of flowable fill.

Chapter 6 summarizes the research and its conclusions and offers recommendations

for further research.














CHAPTER 2
LITERATURE REVIEW

2.1 Introduction

A comprehensive literature search was conducted to identify and examine existing

publications dealing with the following subject matter:

* strength
* set time
* cement; and
* admixtures.

2.2 Flowable Fill Technology

2.2.1 Introduction

Flowable fill, also referred to as controlled low strength material (CLSM), is a

relatively new technology whose use has grown over the years. It describes a fill

technology that is used in place of compacted backfill. Flowable fill is self-leveling with

a consistency similar to pancake batter; it can be placed with minimal effort and no

vibration or tamping is required.

Flowable fill, or CLSM, is a highly flowable cementitious slurry typically

comprised of water, cement, fine aggregates, and often fly ash and chemical admixtures,

including air-entraining agents, foaming agents, and accelerators. Other names used for

this material are "flowable mortar" and "lean-mix backfill" [8].

Flowable fill is defined by the ACI Committee 229 as a "self compacting

cementitious material that is in a flowable state at the time of placement and that has a

specified compressive strength of 200 lb/in2 or less at 28 days" [6, p. 56]. Flowable fill









has a low cementitious content for reduced strength development, which makes future

excavation a possibility. This mixture is capable of filling all voids in irregular

excavations and hard-to-reach places (such as under and around pipes) and hardens in a

matter of a few hours without the need for compaction in layers.

2.2.2 Types of Flowable Fill

There are a variety of CLSM types available for various engineering purposes. The

most obvious distinction between types is the possible need for future removal. Thus, the

current FDOT specification divides flowable fill into two main classes: (i) excavatable

fill; and (ii) nonexcavatable fill.

Controlled low strength material (CLSM) excavatability is dependent on many

factors including binder strength, binder density, aggregate quantity, aggregate gradation,

and the excavating equipment used. The National Ready Mixed Concrete Association

(NRMCA) recommends that excavatable CLSM mixes have a 20+ psi compressive

strength at 3 days, a 30+ psi compressive strength at 28 days, and ultimate compressive

strength less than 150 psi. Compliance with these recommendations is typically

established with cylinder compressive strength tests [2].

2.2.3 Advantages of Using Controlled Low Strength Material (CLSM)

There are various inherent advantages of using CLSM over compacted soil and

granular backfills. Some of these are listed below [8].

1. It has a fast setup time.

2. It hardens to a degree that precludes any future trench settlement.

3. The extra cost for the material, compared to compacted backfill, is offset by the fact
that it eliminates the costs for compaction and labor, reduces the manpower
required for close inspection of the backfill operation, requires less trench width,
and reduces the time period and costs of public protection measures.









4. There are no problems due to settlement, frost action, or localized zones of
increased stiffness.

5. Flowable fill mix designs can be adjusted to meet specific fill requirements, thus
making the fill more customized and efficient.

6. Flowable fill is stronger and more durable than compacted soil or granular fill.

7. During placement, soil backfills must be tested after each lift for sufficient
compaction. Flowable fill self-compacts consistently and does not need this
extensive field testing.

8. It allows fast return to use by traffic.

9. Flowable fill does not form voids during placement nor settle or rut under loading.

10. Since it reduces exposure to possible cave-ins, flowable fill provides a safer
environment for workers.

11. It reduces equipment needs.

12. It makes storage unnecessary because ready-mix trucks deliver flowable fill to the
jobsite in the quantities needed.

13. Flowable fill containing fly ash benefits the environment by making use of this
industrial waste by-product.

These benefits also include reduced labor and equipment costs (due to self-leveling

properties and absence of need for compaction), faster construction, and the ability to

place material in confined spaces. The relatively low strength of CLSM is advantageous

because it allows for future excavation, if required. Another advantage of CLSM is that

it often contains by-product materials, such as fly ash and foundry sand, thereby reducing

the demands on landfills, where these materials might otherwise be deposited.

Despite these benefits and advantages over compacted fill, the use of CLSM is not

currently as widespread as its potential might warrant. CLSM is somewhat a hybrid

material; it is a cementitious material that behaves more like a compacted fill. As such,

much of the information and discussions on its uses and benefits are lost between

concrete materials engineering and geotechnical engineering. Although there is









considerable literature available on the topic, CLSM is often not given the level of

attention it deserves by either group.

2.2.4 Engineering Characteristics of CLSM

When a CLSM mixture is designed, a variety of engineering parameters needs to be

evaluated prior to, during, and after placement in the field. Optimum conditions for each

parameter depend on the application. Typically, blends will be proportioned and the

desired characteristics will be tested according to the appropriate standard procedures.

Although not all parameters need to be evaluated, the following are of major consequence

to the effectiveness of the CLSM mixture [9]:

1. strength development
2. time of set
3. flowability and fluidity, or consistency of the mixture
4. permeability
5. consolidation characteristics
6. California bearing-ratio test; and
7. freeze-thaw durability.

The performance criteria for flowable fills are outlined in ACI 229R-94. Flowable

fill is a member of the family of grout material. ACI Committee 229 calls it "controlled

low strength material," and does not consider it concrete. If it is anticipated or specified

that the flowable lean-mix backfill may be excavated at some point in the future, the

strength must be much lower than the 1200 psi that ACI uses as the upper limit for

CLSM. The late-age strength of removable CLSM materials should be in the range of 30

to 150 psi as measured by compressive strength in cylinders [8].

2.2.5 Uses of Flowable Fill

CLSM is typically specified and used as compacted fill in various applications,

especially for backfill, utility bedding, void fill and bridge approaches. Backfill includes

applications such as backfilling walls, sewer trenches, bridge abutments, conduit









trenches, pile excavations, and retaining walls. As structural fill, it is used in foundation

subbase, subfooting, floor slab base, and pipe bedding. Utility bedding applications

involve the use of CLSM as a bedding material for pipes, electrical and other types of

utilities, and conduits. Void-filling applications include the filling of sewers, tunnel

shafts, basements or other underground structures such as road base, mud jacking,

subfooting, and floor slab base. CLSM is also used in bridge approaches, either as a

subbase for the bridge approach slab or as backfill with other elements. Other uses of

flowable fill include abandoned underground storage tanks, wells, abandoned utility

company vaults, voids under pavement, sewers and manholes, and around muddy areas

[8,10].

Conventional backfill in trenches and around small structures usually involves

placement of aggregate material in thin layers with labor-intensive compaction. Poorly

constructed backfill or lack of control of compaction often creates excessive settlement of

the road surface and may produce unacceptable stresses on buried utilities and structures.

Use of CLSM removes the necessity for mechanical compaction with the associated

safety hazards for workers. It can also provide more efficient placement and may permit

reduced trench dimensions [10].

2.2.6 Delivery and Placement of Flowable Fill

CLSM can be delivered in ready-mix concrete trucks and placed easily by chute in

a flowable condition directly into the cavity to be filled or into a pump for final

placement. For efficient pumping, some granular material is needed in the mixture [8].

CLSM can even be transported as a dry material in a dump truck. It can be proportioned

to be self-leveling thus not requiring compaction, and so can be placed with minimal









effort without vibration or tamping. It hardens and develops strength, and can be

designed to meet specific strength criteria or density requirements.

Precautions against the following need to be taken into account while working with

flowable fill [8]:

1. Fluidized CLSM is a heavy material and during placement (prior to setting) will
exert a high fluid pressure against any forms, embankment, or wall used to contain
the fill.

2. Placement of flowable fill around and under tanks, pipes, or large containers such
as swimming pools, can cause the container to float or shift.

2.2.7 Limits

Although CLSM mixtures provide numerous advantages compared to conventional

earth backfilling, some limitations must be considered when these materials are used.

Limitations include the following [11]:

1. Requires lighter-weight pipes to be anchored.

2. Needs to undergo confinement before setting.

3. May not allow higher-strength mixtures to be excavated.

4. Forms or pipes used must resist lateral pressures (lateral pressure is applied while
in the fluid condition).

2.3 Specifications, Test Methods, and Practices

2.3.1 Introduction

The Environmental Protection Agency (EPA) recommends that procuring agencies

use ACI229R-94 and the ASTM standards listed in Table 2-1 when purchasing flowable

fill or contracting for construction that involves backfilling or other fill applications.

More than 20 states have specifications for flowable fill containing coal fly ash. They

include California, Colorado, Delaware, Florida, Georgia, Illinois, Indiana, Kansas,

Kentucky, Maryland, Massachusetts, Michigan, Minnesota, Nebraska, New Hampshire,









New Mexico, North Carolina, Ohio, Texas, Washington, West Virginia, and Wisconsin.

The history of the current standard test methods for CLSM is rather short but quite

important [12].

Table 2-1. Current ASTM standards on controlled low strength material (CLSM)
ASTM
Specification Title
Number
D 4832-02 Standard Test Method for Preparation and Testing of Controlled Low
Strength Material (CLSM) Test Cylinders
D 5971-01 Standard Practice for Sampling Freshly Mixed Controlled Low Strength
(PS 30) Material
D 6023-02 Standard Test Method for Unit Weight, Yield, Cement Content and Air
(PS 29) Content (Gravimetric) of Controlled Low Strength Material (CLSM)
D 6024-02 Standard Test Method for Ball Drop on Controlled Low Strength Material
(PS 31) (CLSM) to Determine Suitability for Load Application
D 6103-97 Standard Test Method for Flow Consistency of Controlled Low Strength
(PS 28) Material

One or more of the following ASTM test methods listed in Table 2-1 are used

primarily as a quality measure during backfilling and construction in the following areas

[8,12]:

1. Sampling-Obtaining samples of the flowable fill for control tests shall be in
accordance with Practice D 5971.

2. Unit weight, yield (ASTM C 138) and air content (ASTM C 231)-Determining the
unit weight, yield, or air content of a flowable fill mixture shall be in accordance
with Test Method D 6023.

3. Flow consistency-Measuring the flowability of the flowable fill mixture shall be in
accordance with Test Method D 6103.

4. Compressive strength-Preparing compressive strength cylinders and testing the
hardened material for compressive strength shall be in accordance with Test
Method D 4832. In addition to comparing to specification requirements, the
compressive strength can provide an indication of the reliability of the mix
ingredients and proportions.

5. Load application-Determining when the hardened mixture has become strong
enough to support load, such as backfill or pavement, shall be done in accordance
with Test Method D 6024 [5].









6. Penetration resistance-Tests such as ASTM C 403 may be useful in judging the
setting and strength development up to a penetration resistance number of 4000
(roughly 100 psi compressive cylinder strength).

7. Density tests-These are not required since it becomes rigid after hardening.

8. Setting and early strength-These may be important where equipment, traffic, or
construction loads must be carried. Setting is judged by scraping off loose
accumulations of water and fines on top and seeing how much force is necessary to
cause an indentation in the material. ASTM C 403 penetration can be run to
estimate bearing strength.

9. Flowability of the CLSM-Flowability is important, so that the mixture will flow
into place and consolidate.

Many states have developed specifications governing the use of CLSM. In some

cases, these are provisional. However, specifications differ from state to state, and

moreover, a variety of different test methods are currently being used to define the same

intended properties. This lack of conformity, both on specifications and testing methods,

has also hindered the proliferation of CLSM applications. There are also technical

challenges that have served as obstacles to widespread CLSM use. For instance, it is

often observed in the field that excessive long-term strength gain makes it difficult to

excavate CLSM at later stages. This can be a significant problem that translates to added

cost and labor. Other technical issues deserving attention are the compatibility of CLSM

with different types of utilities and pipes, and the durability of CLSM subjected to

freezing and thawing cycles [13].

2.3.2 ASTM Standard Test Methods

2.3.2.1 Standard Test Method for Preparation and Testing of CLSM Test Cylinders
(ASTM D 4832-02)

Cylinders of CLSM are tested to determine the compressive strength of the

material. The cylinders are prepared by pouring a representative sample into molds,

curing them, removing the cylinders from the molds, and capping the cylinders for









compression testing. The cylinders are then tested by machine to obtain compressive

strengths by applying a load until the specimen fails. Duplicate cylinders are required

[14].

The compressive strength of a specimen is calculated as follows:

P
/f =- (2-1)
A

where fc = compressive strength in pounds per square inch (lb/in2);
P = maximum failure load attained during testing in pounds (lb); and
A = load area of specimen in square inches (in2).

This test is one of a series of quality control tests that can be performed on CLSM

during construction to monitor compliance with specification requirements.

2.3.2.2 Standard Practice for Sampling Freshly Mixed CLSM (ASTM D 5971-96)

This practice explains the procedure for obtaining a representative sample of the

freshly mixed flowable fill as delivered to the project site for control and properties tests.

Tests for composite sample size shall be large enough to perform so as to ensure that a

representative sample of the batch is taken. This includes sampling from revolving-drum

truck mixers and from agitating equipment used to transport central-mixed CLSM [14].

2.3.2.3 Standard Test Method for Unit Weight, Yield, Cement Content and Air
Content (Gravimetric) of CLSM (ASTM D 6023-96)

This practice explains the procedure for obtaining a representative sample of the

freshly mixed flowable fill (as delivered). The density of the CLSM is determined by

filling a measure with CLSM, determining the mass, calculating the volume of the

measure, then dividing the mass by the volume. The yield, cement content, and air

content of the CLSM are calculated based on the masses and volumes of the batch

components [14].









a) Yield:

Y = W (2-2)
W

where Y = volume of CLSM produced per batch in cubic feet (ft3);
W = density of CLSM in pounds per cubic foot (lb/ft3); and
W1 = total mass of all materials batched, lb.

b) Cement content:


N = N (2-3)
Y

where N = actual cement content in pounds per cubic yard (lb/yd3);
N, = mass of cement in the batch, lb; and
Y = volume of CLSM produced per batch in cubic yards (yd3).

c) Air content:

T-W
A = *100 (2-4)
T

where A = air content (percent of voids) in the CLSM;
T = theoretical density of the CLSM computed on an air free basis, lb/ft3;
and
W = density of CLSM, lb/ft3.

2.3.2.4 Standard Test Method for Ball Drop on CLSM to Determine Suitability for
Load Application (ASTM D 6024-96)

This test method is used primarily as a field test to determine the readiness of the

CLSM to accept loads prior to adding a temporary or permanent wearing surface. A stan-

dard cylindrical weight is dropped five times from a specific height onto the surface of

in-place CLSM. The diameter of the resulting indentation is measured and compared to

established criteria. The indentation is inspected for any free water brought to the surface

from the impact [14].









2.3.2.5 Standard Test Method for Flow Consistency of CLSM (ASTM D 6103-96)

This test method determines the fluidity and consistency of fresh CLSM mixtures

for use as backfill or structural fill. It applies to flowable CLSM with a maximum

particle size of 19.0 mm (3/4 in.) or less, or to the portion of CLSM that passes a

19.0-mm sieve. An open-ended cylinder is placed on a flat, level surface and filled with

fresh CLSM. The cylinder is raised quickly so the CLSM will flow into a patty. The

average diameter of the patty is determined and compared to established criteria [14].

2.3.3 Other Currently Used and Proposed Test Methods

The American Concrete Institute (ACI) classifies CLSM as a mixture design

having a maximum 28-day compressive strength of 1200 lb/in2. A CLSM mixture that is

considered to be excavatable at a later age using hand tools should have a compressive

strength lower than 101.5 psi at the 28-day stage [14]. This is used to minimize the cost

of excavating a mix at a later stage. Two field requirements that should be specified to

ensure quality control and ease of placement are a minimum level of flowability or

consistency and a specified method of measuring it. Measuring flowability utilizing the

flow cone method is most applicable for grout mixtures that use no aggregate filler. A

maximum flow cone measurement of 35 seconds or a minimum slump of 9 in. would be

two practical design parameters. Other methods to specify CLSM consistency have also

been suggested. One such method is very similar to the ASTM standard test

specification, "Flow Table for Use in Tests of Hydraulic Cement" (C 230), for deter-

mining the consistency or flow of mortar mixtures [14].

Permeability of the CLSM mixtures has been measured using the ASTM "Test

Method for Measurement of Hydraulic Conductivity of Saturated Porous Materials Using

a Flexible Wall Permeameter" (D 5084). Loss on ignition of CLSM mixtures, and









mineralogy of the hardened CLSM has been determined on the basis of similar tests for

cement. It has been determined that aggregate containing up to 21% finer than 0.075 mm

could be used to produce a flowable fill mix meeting National Ready Mixed Concrete

Association (NRMCA) performance recommendations [14].

The gradation has been determined per ASTM C 136-01, "Standard Test Method

for Sieve Analysis of Fine and Coarse Aggregates" and ASTM C 117, "Standard Test

Method for Materials Finer than 75 [tm (No. 200) Sieve in Mineral Aggregates by

Washing." Also, AASHTO M43 #10 screening aggregate specifications [15] has been

used to determine the suitability of utilizing the compliance of aggregates used with these

standards [14].

A new ASTM standard, "Standard Practice for Installing Buried Pipe Using

Flowable Fill" has been proposed, which describes how to use flowable fill for installing

buried pipe. ASTM Committee C 3 on Clay Pipe has already initiated mentioning the use

of flowable fill in the Standard C 12 that covers installation of clay pipe [14].

A summarized overview of the test standards currently in use and that of provi-

sional test methods is as follows [14]:

* Provisional methods of testing

1) AASHTO Designation: X7 (2001)-"Evaluating the Corrosion Performance
of Samples Embedded in Controlled Low Strength Material (CLSM) via
Mass Loss Testing"

2) AASHTO Designation: X8 (2001)-"Determining the Potential for
Segregation in Controlled Low Strength Material (CLSM) Mixtures"

3) AASHTO Designation: X9 (2001)-"Evaluating the Subsidence of Controlled
Low Strength Materials (CLSM)."









* Other ASTM test methods used in CLSM technology

1) ASTM C231-97-" Standard Test Method for Air Content of Freshly Mixed
Concrete by the Pressure Method"

2) ASTM C403/C 403M-99-"Standard Test Method for Time of Setting of
Concrete Mixtures by Penetration Resistance"

3) ASTM D560-96-"Standard Test Methods for Freezing and Thawing
Compacted Soil-Cement Mixtures"

4) ASTM D5084-90 (Reapproved 1997)-"Standard Test Method for Measure-
ment of Hydraulic Conductivity of Saturated Porous Materials Using a
Flexible Wall Permeameter"

5) ASTM G51-95 (Reapproved 2000)-"Standard Test Method for Measuring
pH of Soil for Use in Corrosion Testing."

2.3.4 Specifications by the State Departments of Transportation

From a survey of six southeastern states (shown in Table 2-2) carried out by Riggs

and Keck [12], it is apparent that all of the specifications were issued after 1990, and so

the use of CLSM is relatively new to standard transportation road construction. Tables

2-3 and 2-4 show the comparison of similarities and differences for various requirements

based on the survey.

Table 2-2. States surveyed and their specification on flowable fill
State Specification and Title of Section Issue Date
Alabama Section 260, Low Strength Cement Mortar 1996
Florida Section 121, Flowable Fill" (revised 1996) 1997
Georgia Section 600, Controlled Low Strength Flowable Fill 1995
North Carolina Controlled Low Strength Material Specification 1996
South Carolina Specification 11, Specification for Flowable Fill 1992
Virginia Special Provisions for Flowable Backfill 1991

According to the survey, the general acceptance age is 28 days with two states

having 56-day requirements (Table 2-3). As a result of the high levels of pozzolans in

many CLSM mixtures, there can be significant strength increases after 28 days. Several









states have both excavatable and nonexcavatable mixtures. If the CLSM is to be

removed at a later date, its strength must be limited to less than 300 psi, which can be

assured only if later age strengths are evaluated [12].

Table 2-3. Specified acceptance strengths and ages

State Age Strength, psi (MPa in parentheses)
State ( s ----------------
(days) Minimum Maximum
Alabama 28 80 (0.55) 200 (1.4)
Florida 28 100 (0.7) 125 (0.9)
Georgia 28 100 (0.7) 125 (0.9)
North Carolina 28; 56 125 (0.9) 150 (1.0)
South Carolina 28; 56 80 (0.55) 125 (0.86)
Virginia 28 30 (0.2) 200 (1.4)
Note: Maximum strengths are restricted to enable excavation at later stages, if desired or
needed.

Table 2-4. Suggested mixture proportions, lb/yd3 (values in kilograms per cubic meter,
kg/m3, are in parentheses)
Fine
State Cement Pozzolan Aggregate Water Air Range
Aggregate
Alabama 61 (36) 331 (196) 2859 (1696) 509 (302) Not given
185 (110) 0 2637(1586) 500(297)
195(116) 572(339) 2637(1586) 488(290)
195(116) 572(339) 2673(1586) 488(290)
517(307) 0 413 (245) 341(202)
Florida 75-100 (44-89) 0 (a) (b) 5-35
75-150 (44-89) 150-600 (89-356) (a) (a) (b) 15-35
Georgia 75-100 (44-89) 0 (a) (b) 15-35
75-150 (44-89) 150-600 (89-356) (a) (a) (b) 5-15
N. Carolina 40-100 (24-59) (a) (a) (b) 0-35
100-150 (59-89) (a) (a) (a) (b) 0-35
S. Carolina 50 (30) 600 (356) 2500 (1483) 458 (272) None (c)
50 (30) 600 (356) 2500 (1483) 541 (321) None (c)
Virginia Contractor must submit his own mixture ("mix design")


Note:


(a) Proportion to yield 1 yd3 (1 min3)
(b) Proportion to produce proper consistency
(c) Air up to 30% may be used if required.









2.3.5 Use of Flowable Fill in the State of Florida

Flowable fill has been used throughout the state of Florida as a construction

material. The FDOT has used the material for bedding, encasements, tank enclosures,

pipes, and general backfill for trenches. Occasionally, the use of flowable fill has been

specified for placement under a base with a set time of four hours or more prior to the

placement of the base materials [16].

The current specification divides the flowable fill into two classes: excavatable and

nonexcavatable. The maximum allowable 28-day compressive strength of excavatable

flowable fill is 100 psi. The minimum compressive strength for nonexcavatable flowable

fill is 125 psi. The suggested range of cement and fly ash has been specified for each

class of excavatable and nonexcavatable fill. Prior to use on projects, flowable fill mix

designs must be approved by FDOT. The approval of the mix design is based on the

specified range of material and laboratory test data, such as air content, compressive

strength, and unit weight [16].

2.3.5.1 Material Specifications (Section 121-2)

According to Section 121 of the FDOT "Standard Specifications for Roadway and

Bridge Construction," the material requirements a flowable fill mix design must meet in

order to be approved by FDOT are noted in Table 2-5 below [16].

Table 2-5. FDOT materials specification requirements
Fine aggregatea ................................................ ......... ...... ........... Section 902
Portland cement (Types I, II, or III).................. ..................... Section 921
Fly ash, slag and other pozzolanic materials .............................. Section 929
Air-entraining admixturesb .............. ..................... Section 924
W ater................................................................. ... ........... Section 923
aAny clean fine aggregate with 100% passing a 3/8-in. (9.5-mm) mesh sieve and not more than
15% passing a No. 200 (75 .im) sieve may be used.
bHigh air generators or foaming agents may be used in lieu of conventional air-entraining
admixtures and may be added at jobsite and mixed in accordance with manufacturer's
recommendation.










All materials used should meet other specification requirements on a consistent

basis (see Section 2.3.5.3 below).

2.3.5.2 Construction Requirements and Acceptance (Section 121-5, 121-6)

FDOT specifications require the ambient air temperature to be 400 F (40 C) or

higher and the mix be delivered at a temperature of 500 F (100 C) or higher. FDOT does

not permit placement during rain or when the temperature is below 400 F. Specification

requires the material to remain undisturbed until it reaches a penetration resistance of 35

psi or higher. A soil penetrometer (ASTM C 403, "Standard Test Method for Time of

Setting of Concrete Mixtures by Penetration Resistance") is used to measure setting time

[16].

2.3.5.3 Guideline for Construction Requirements and Acceptance (Section 121-5,
121-6)

To assist in designing a flowable fill mix, Section 121 of the specifications

provides a guideline shown in Table 2-6 for one to use in preparing a mix design [16].

Table 2-6. FDOT flowable fill mix design
Excavatable Nonexcavatable
Cement, Type I 75-100 lb/yd3 75-150 lb/yd3
(45-60 kg/m3) (45-90 kg/m3)
Fly ash None 150-600 lb/yd3
(90-335 kg/m3)
Water a a
Airb 5-35% 5-15%
28-day compressive strengthb Maximum 100 psi Minimum 125 psi
(690 kPa) (860 kPa)
Unit weight (wet) 90-110 lb/yd3 100-125 lb/yd3
(1440-1760 kg/m3) (1600-2000 kg/m3)
aMix design shall produce a consistency that will result in a flowable self-leveling product
at a time of placement.
bThe requirements for percent air, compressive strength and unit weight are for laboratory
designs only and are not intended for jobsite acceptance requirements. Fine aggregate
shall be proportioned to yield 1 yd3 (1 m3).









2.4 Early Set and Strength Development

2.4.1 Introduction

The early strength of flowable fill in a plastic state comes primarily from the

friction of particles of its constituents. This theory originates from the behavior of

particles in slurry flow, powder technology, and tribology (the science and technology of

interacting surfaces in relative motion and all related practices, including friction,

lubrication, and wear). Although slurry flow does not have any cementing agents, an

explanation of the role of particle friction in slurry is an important base to fully

understanding the early strength of flowable fill.

The end of the plastic state is indicated by hydration of cement particles and the

role of cohesion appears to begin in this stage. The hydration process in flowable fill can

be explained based on the chemical reaction of cement and fly ash in the concrete.

2.4.2 Behavior of Slurries

The behavior of slurries as described by Kendall is similar to that of coulomb

materials, with a flow stress dependent on the high friction between the solid grains [17].

Three simple tests were conducted by Kendall, a plastimeter test, an extrusion test, and a

bubble collapse test. The result was that the slurries became unmoldable, nonextrudable

or noncompactable when the solid grains in the slurry became frictionally locked

together. However, this effect can be prevented by addition of a polymer lubricant which

reduces friction between the grains thereby improving slurry flow.

According to an experiment by Kendall involving wet concrete slurry, if the slurry

is truly plastic, then at a pressure equal to the yield pressure, one's foot would sink into

the slurry (as in the Bingham model) [17]. In that experiment, the foot did not sink

because the cement grains under the foot were pushed together, experienced friction, and









so resisted flow. However, when some polymer lubricant is mixed into the slurry, the

friction between the grains is reduced and the foot does sink through the material. This is

similar to the addition of fly ash particles in flowable fill.

Reynolds, in 1885, conducted an experiment in which a rubber balloon was filled

with sand and water. When the water was excessive, the material was plastic. However

when water was withdrawn from the balloon, the material suddenly became rigid or

dilatant. The rigidity resulted from the higher friction of sand particles since the particles

were pushed closer together, similar to the disappearance of bleeding water in CLSM.

2.4.3 Early Hydration of Cement Particles

In the reaction between cement and water, setting is caused by a selective hydration

of cement compounds. The two compounds first to react are tricalcium aluminate (C3A)

and tricalcium silicate (C3S). However, the addition of gypsum delays the formation of

calcium aluminate hydrate, and instead, ettringite precipitates first from the reaction of

C3A and gypsum, then calcium silicate hydrate (C-S-H) forms from the C3S reaction.

Apart from the rapidity of formation of crystalline products, the development of film

around cement grains and a mutual coagulation of paste components have also been

suggested as factors in the development of setting.

According to Jawed and Skalny, once the nucleation and crystallization of

hydration products end the dormant period, hydration is accelerated by the presence of fly

ash [1]. Fly ash particles provide additional surfaces for the precipitation of the hydration

products, which would otherwise be formed on the surface of the C3S and hinder its

interaction with water. By this account, the jump in early strength development in

flowable fill would occur at the end of the induction period.









2.4.4 Influence of Water to the Hydration of Cement

Popovic concluded that the primary factors that influence the times of setting of a

given cement are curing temperature, water/cement (w/c) ratio, and fineness of cement

[2,18]. The times required to set based on the w/c ratio are illustrated in Figure 2-1

below from Soroka [19]. This figure shows that the higher the w/c ratio, the longer the

time required to set up. However, this is only valid for a small range of w/c ratios, which

is 0.25 to 0.85.

16.00
14.00 -
12.00 -
o 10.00 -
S8.00 Initial Set
a 8.00 -
f m Final Set
6.00 *
E 4.00 *
2.00
0.00 -
0.00 0.20 0.40 0.60 0.80
w/c ratio, by weight

Figure 2-1. Influence of water/cement (w/c) ratio on the setting of Portland cement paste
[19]

A study by Soroka shows that initially the w/c ratio does not significantly affect the

rate of hydration as indicated by the constant amount of water combined for all mixes

with different w/c ratios [19]. Later, as the w/c ratio lowers, the rate of hydration

decreases, indicated by the smaller amount of water combined in the reactions. Soroka

stated that the lower the w/c ratio, the lower the degree of hydration and the average rate

of hydration. Soroka suggested that this slower rate of hydration may be attributed to the

decrease in the space available for the hydration product at a lower w/c ratio.









2.4.5 Effects of Set Accelerator on Hydration of Cement

In the case of calcium chloride accelerator, Rixom and Mailvaganam concluded

that there is no chemical reaction between C3S or dicalcium silicate (C2S) with calcium

chloride, although their rate of reaction is increased [20]. They added that calcium

chloride does not react significantly with cement paste for a period of 2 to 6 hours after

mixing, although rapid setting can occur in this period. Formations of new hydration

products between C3A, gypsum, and calcium chloride may be present. These hydration

products influence the setting behavior of the mix and contribute to higher strength

because more hydration products are formed.

2.4.6 Set Time

In practice, knowledge of the rate of reaction is important because the rate

determines the time of setting and hardening. The initial reaction must be slow enough to

allow time for the flowable fill to be transported and placed. Once it has been placed,

rapid hardening is desirable. In the setting of cement paste, Neville indicates that setting

refers to a change from a fluid to a rigid state and hardening refers to gain of strength

[21]. Although during setting the paste acquires some strength, for practical purposes it

is convenient to distinguish setting from hardening.

Recently, only hardening time has been recognized. Some studies reported that

hardening time refers to the time period required for flowable fill to go from a plastic

state to a hardened state with sufficient strength to sustain loading [21]. These studies

also pointed out that the hardening process is influenced by excess water leaving the

mixture. Excess water leaving the mixture makes the aggregate particles come into

surface contact and the mixture becomes rigid. Also, the cement content has a major

influence on the hardening time.









Some research reports that hardening time takes about 3 to 5 hours under normal

conditions. In practice, the extent of hardening is judged by the ability to withstand foot

traffic without surface depression [21].

2.4.7 Strength Development

According to Diamond, the local packing of flocs of cement particles near surfaces

of aggregates or other solids in concrete is poor, and much solution-filled space remains

in the vicinity despite general consolidation of the concrete [22]. Concrete contains little,

if any, bulk uninterrupted cement paste. Diamond pointed out that when water is mixed

with cement, the formation of definite shells of hydration product around cement grains is

the first micro structure development. This occurs after several hours. The shells are

typically of the order of 1 micron in thickness and are usually composed of C-S-H with

some local areas rich in calcium hydroxide (CH) and occasional inward or outward

extensions of ettringite needles or thin calcium monosulfate plates.

A function of fly ash in flowable fill is to provide flowability and fill interparticle

voids if sand is in the mixture. However, when fly ash reacts with cement and water, the

micro structural development is affected. Shells are not only formed around the cement

particles but also around fly ash grains. The shells become tied into a developing skeletal

structure induced by the growth of the cement hydration product. The rate of shell

development around the fly ash particles varies with chemistry and reactivity in the fly

ash. With a fly ash that is low in calcium such as class F fly ash, the shell formation is

followed by a slow reaction on the surface of the fly ash sphere inside the shell.

According to Helmuth in 1987, there has been disagreement concerning the time

the Pozzolanic reaction begins [23]. Some previous workers reported no important

reaction before 28 days but some reported very early reaction. Helmuth said that the









reaction appears to begin at an early age, but it does not contribute strength until later.

However, there are conflicting reports about the effect of fly ash in cement hydration.

Some reports indicate an acceleration of C3S hydration, but Jawed and Skalny reported a

pronounced delay of the main heat evolution peak of C3S in the presence of fly ash [1].

The same situation also occurred for C3A.

2.4.8 Use of Mineral Admixture (Fly Ash and Granulated Ground Blast Furnace
Slag) in Flowable Fill

A review of the relationship of fly ash and slag as an integral component of the

flowable fill mixture was investigated. Both materials are considered to be mineral

admixtures.

2.4.8.1 Fly ash

Fly ash is a pozzolanic material. Pozzolan is defined as a siliceous or alumino-

siliceous material that possesses little or no cementitious value. Fly ash is a powder

residue that comes from the combustion of pulverized coal in electric power generating

plants. Fly ash is primarily silicate glass containing silica alumina, iron, and calcium.

The minor constituents are magnesium, sulfur, sodium, potassium, and carbon.

According to research by Halverson et al., fly ash is the term generally used to

describe the ash and non-combustible minerals that are released from coal during

combustion and that "fly" up and out of the boiler with the flue gases [24]. The main

constituents in fly ash are oxides, sulfates, phosphates, partially converted dehydrated

silicates, and other inorganic particulate matter residue from coal combustion [25].

Physically, fly ash is made up of fine, powdery particles, which are predominantly

spherical, solid or hollow, and generally in an amorphous state, although uncombusted

carbon in fly ash is usually in the form of angular solid particles [26]. Fly ash has a









specific gravity between 2.1 to 3.0 and a specific surface area ranging from 170 to 1000

m2/kg, as determined by the Blaine air permeability test. The Blaine air permeability test,

in accordance to ASTM C 204, measures fineness of a material based on its permeability

to air under specified conditions.

Chemical properties of fly ash are much less consistent than physical properties, as

fly ash is an inherently variable material. Fly ash variability is due to widespread

differences in inorganic chemical constituents of the source coal, methods of coal

preparation, combustion conditions, furnace type, and the ash collection, handling, and

storage conditions at each utility site [27]. Since utilities may not have all these factors in

common, fly ash from different facilities is likely to vary significantly. Even within one

power plant, however, fly ash characteristics can change greatly over time based on load

and operating conditions over a 24-hour period [28]. Consequently, lack of fly ash

consistency is a serious disadvantage in utilizing ash for extensive and economic

beneficial uses.

Despite the uncertainty and variability of fly ash properties, some ash character-

istics can be correlated to the physical and chemical characteristics of the fuel source,

particularly coal. For example, bituminous coal fly ash is predominantly composed of

silica, alumina, iron oxide, and calcium, as well as a variable amount of unburned carbon.

On the other hand, sub-bituminous and lignite coal fly ashes exhibit higher concentra-

tions of calcium and magnesium oxide and lower amounts of silica and iron oxide. These

coals also usually produce fly ash with lower carbon content than that of anthracite [26].

Fly ash color generally varies from tan to gray and black, as a direct function of the

carbon content remaining in the ash [29]. Ash from lignite or sub-bituminous coal is









generally tan to beige in color, indicating a low carbon content and the presence of lime

or calcium. Bituminous coal fly ash contains higher unburned carbon and is therefore a

shade of gray. Lighter tints of gray can indicate higher quality ash [26]. Indicated by the

fly ash color, the quantity of unburned carbon carried over from combustion into the fly

ash is measured by the loss on ignition (LOI). High LOI values are undesirable, as they

indicate that the combustion of the source coal is incomplete and raw material is being

carried through to a waste stream rather than being utilized for energy production. LOI is

also a significant chemical property of fly ash and serves as a primary indicator to

whether the ash will make a suitable replacement for cement in concrete production. Fly

ash used as a cement replacement is required by ASTM C618 to have below 6% carbon

content, however, it is preferred to have at or below 3% carbon by members of the

cement and concrete industry [30].

ASTM C618 groups pozzolanic material into three classes: N, F, and C. Class N

refers to natural pozzolans, classes F and C differentiate fly ash of different chemical and

physical properties. Class F is composed of ash produced from burning lignite or

bituminous coal [31]. This class exhibits pozzolanic reactivity but seldom shows any

self-cementitious behavior. Class F fly ash is also termed "low calcium ash," as it

contains less than 6% calcium oxide (CaO) weight. On the other hand, Class C fly ash is

generated from burning lignite or sub-bituminous coal and typically has higher

concentrations of CaO, generally above 15% by weight [28]. Class C fly ash also

exhibits both pozzolanic and self-cementitious behavior. The function of fly ash in

flowable fill is to provide flowability and to fill interparticle voids for sands in the

mixture.









2.4.8.2 Slag

The full correct name for slag is ground granulated blast-furnace slag. In mixtures

of flowable fill and concrete, slag is considered as a cementitious material that can set

and harden in the presence of water. Slag is the heavy, coarse, granular, incombustible

particles remaining in the bottom of coal-fired boilers [32]. Slag is ash, a residue from

combustion in a dry-bottom furnace, consisting of fused ash particles with a size

distribution typically between 75 [im and 2 mm and a composition that depends heavily

on the coal source [28]. Essentially, this product is a waste product from the blast

furnace process for manufacturing of steel and iron. Granulated blast-furnace slag

particles have very porous surface textures that create potential for deterioration during

collection, storage, handling, and use [26]. It is primarily made up of silica, alumina, and

iron, as well as low amounts of calcium, magnesium sulfates, and other inorganic

materials [26]. The chemical characteristics are derived from its coal source and not

operating parameters. Based on its chemical composition and wide range of sizes, slag is

not pozzolanic like fly ash, and therefore, has more limited applications in the cement and

concrete industry [28]. Additionally, its corrosivity, conferred by high salt content and

potentially low pH, limits its use in embankments, road base, subbase, or backfill, where

potential contact with metal structures exists [26].

Slag is often used in the construction industry as a replacement for ordinary

Portland cement. Since slag is a by-product of the iron production process and contains

calcium silicates and aluminosilicates, its cementitious material has been touted for both

its strength and durability-enhancing characteristics when used in concrete. Ground

granulated blast furnace slag also has a lower heat of hydration and, hence, generates less

heat during concrete production and curing. As a result, slag is a desirable material to









utilize in concrete placements where control of temperature is an issue. Percentage

replacements by weight of slag for cement have ranged from 10 to 90%.

During the early hydration of the slag, the cement releases alkali metal ions and

calcium hydroxides. The glassy slag structure is broken down and dissolved by the

hydroxyl ions. Initially, the reaction of the slag is with alkali hydroxide; later, the

reaction is primarily with calcium hydroxide [33]. As hydration continues long-term, the

cement continues to precipitate calcium hydroxide and grow rings of C-S-H inward from

the original grain surface. Slag, on the other hand, develops more C-S-H, contributing to

strength, density, and chemical resistance [34].

ASTM C 989 divides ground granulated blast-furnace slag into three strength

grades in accordance with their Slag Activity Index (SAI) values: Grade 80, 100, and

120, with Grade 120 being the most active. The SAI is the ratio of the strength of a 50/50

blend of slag and cement to the strength of a plain cement mix at 7 and 28 days. The SAI

is the criterion used for assessing the relative cementitious potential of slag [33]. How-

ever, the cement used as a reference material must meet minimum requirements of

compressive strength and alkali content. The cement used in a particular project may be

less reactive. In general, the early strengths of Grade 120 slag mixes are lower than other

cement mixtures, but usually catch up and then surpass at 7 days and beyond. It is

commonly believed that the other two grades typically exhibit lower strengths. Factors

which affect slag mix performance and strength development are as follows: 1) propor-

tions of cementitious materials, 2) physical and chemical characteristics of the slag,

3) curing conditions, 4) presence and dosage rate of admixtures, 5) characteristics of the

aggregate, and 6) characteristics of the cement.









2.4.8.3 Difference between fly ash and slag

Unlike fly ash which is a pozzolanic, granulated blast-furnace slag is self

cementing. However, when it hydrates by itself, the amount of cementitious products

formed and the rate of formation are insufficient to give adequate strengths for structural

applications. When slag is used in combination with Portland cement, the hydration of

the slag is accelerated in the presence of calcium hydroxide and gypsum. The calcium

hydroxide is also consumed by the slag in a pozzolanic reaction. Proportionally, slag

chemical properties are contain more sulfur trioxide and sulfide sulfur. Thus physically,

slag and fly ash improve the strength gain in flowable fill.

2.4.8.4 Specific applications

Specific applications for both slag and fly ash vary. Both are used extensively in

concrete and flowable fill mixtures. Both materials help to improve the qualities of

flowable fill. One of those qualities involves the workability of flowable fill. For

specific applications involving void filling and backfilling of utility pipes, workability

plays a vital role in flowability of mix and for the complete filling of utility trenches.

2.4.8.5 Mixture proportioning/mixture compliance

According to the review of literature, there is no standard mixture proportioning

adopted by the concrete industry involving mineral admixtures for flowable fill. Many

studies indicate the proportioning of flowable fill is normally specified based on past

experience and the availability of local materials.

A key indicator on a construction jobsite for compliance in a mixture is accom-

plished through visual inspection of the mixture. Excavatable and non-excavatable

flowable fill are distinguishable through mix texture. For example, non-excavatable









mixes contain high amounts of cement and fly ash/slag. On the other hand, excavatable

mixes typically contain low amounts of cement and fly ash.

2.4.9 Effect of Moisture on Strength

In concrete, most of the specifications require that it be maintained and tested in a

saturated state. It has been found that dry concrete has higher strength. Mindess and

Young have indicated that the reasons are not completely understood [35]. It is possibly

due to the change in structure of the C-S-H upon drying. Also, a change in internal

friction and cohesion may cause a lubricating effect due to moisture allowing particles to

more easily slip by each other in shear. In addition, the lower compressive strength of

wet concrete may also occur because of the development of internal pore pressures as a

load is applied.

According to Mindess and Young, the ease and extent of slip depends on the forces

of attraction between particles [35]. If the particles are chemically bonded, no slip can

occur, but if only Van der Waals interactions are operating, slip is theoretically possible.

It appears that measurable slip occurs only when sufficient thickness of water exists

between the particles. The water can reduce the Van der Waals forces sufficiently to

allow slippage more readily; it can be thought of as an analogy to lubrication.

Soroka analyzed the decrease of compressive strength of cement paste based on

Griffith's theory [19]. According to that theory, strength is expected to decrease with an

increase in the moisture content of a material because the presence of absorbed water

reduces specific surface energy. Soroka added that another explanation of the decrease in

strength is the decrease in cohesive forces which results from the presence of absorbed

water. A decrease in the cohesive forces involves weaker bonds between particles.









2.5 Strength Prediction Models

2.5.1 Introduction

Past research done on flowable fill has focused on finding ways to better predict the

long-term strength of flowable fill. This section reviews literature published regarding

methods or models developed to predict the strength of flowable fill.

2.5.2 Hamilton County-Removability Index

Specifications developed by Hamilton County, Ohio, and the City of Cincinnati's,

"Performance Specification for Trench Backfilling Consisting of the Use of Flowable

Fill," uses the removability index for predicting long-term strength of flowable fill [36].

The removability index, used by Hamilton County, takes into consideration the dry

unit weight (w) in conjunction with the 30-day compressive strength (C'). Both are used

to determine removability (excavatability) of a material. A flowable fill mixture is

considered removable if the removability modulus (RE), calculated by the following

equation, is equal to 1.0 or less.

w15 104 r. 0.5
RE 1-- < 1.0 (2-5)
106

where w = dry unit weight (hardened material) (lb/ft3); and
C' = 30-day unconfined compressive strength (lb/in2).

Table 2-7 below shows the removability modulus (RE) values for various combi-

nations of compressive strengths (C') and unit weights (w) calculated by the above

equation. This method of predicting long-term strength is dependent on two variables,

namely, unit weight and the 30-day compressive strength.









Table 2-7. Removability modulus (RE)
Compressive Strength (C')
w (psi)
(lb/ft3)
25 50 75 100 125 150 175 200

50 0.18 0.26 0.32 0.37 0.41 0.45 0.49 0.52
70 0.30 0.43 0.53 0.61 0.68 0.75 0.81 0.86
90 0.44 0.63 0.77 0.89 0.99 1.09 1.17 1.26
110 0.60 0.85 1.04 1.20 1.34 1.47 1.59 1.70
130 0.77 1.09 1.33 1.54 1.72 1.89 2.04 2.18
150 0.96 1.35 1.65 1.91 2.14 2.34 2.53 2.70
Note: RE = 1.15 lb/in2 for hard clay
RE = 1.00 lb/in2 for very stiff clay
RE = 10.26 for 3000 lb/in2 Portland cement concrete
Values in shaded area would not meet the material removability requirement

2.5.3 Bhat's Study

Some studies utilize parameters involved in mix design for predicting compressive

strength for excavatability. A study by Bhat relates the compressive strength of flowable

fill with the mix w/c ratio [37]. Bhat's equation shown below uses a single parameter for

predicting strength at 28 days.

126,905
S, 374 + (2-6)



where Sc = 28-day unconfined compressive strength (KPa); and
w/c = water/cement ratio.

According to Bhat, this model is able to correlate strength to w/c ratio (see Figure

2-2). Using Bhat's equation, the water cement ratios corresponding to a 28-day

compressive strength of 1035 KPa (150 psi) and 690 KPa (100 psi) are approximately 5.8

and 7.4, respectively. The resulting coefficient of determination (R-squared value, R2) is

approximately 80%. This formula used only nonair-entrained flowable fill mixtures

when it was developed.











600

5 400 -

: 300 -



O0
0 C) 0 \
(D 300 -
200 -




0 5 10 15
w/c ratio
Figure 2-2. Bhat's strength prediction model

2.5.4 NCHRP-Study

A study sponsored by the National Cooperative Highway Research Program

(NCHRP), developed two models that predict compressive strength for flowable fill [38].

Equation 2-7, shown below, was developed for predicting strength for air-entrained

mixtures. Equation 2-8 was developed for predicting strength for nonair-entrained

mixtures.

* Prediction equation for air-entrained mixtures

f' = a eb(w/c) (2-7)

a = 0.31 ln(t) + 0.23
b = 0.01 ln(t) 0.27

where f' = compressive strength (Mpa); and
t = age (days).









Equation 2-7 was developed using high air content mixtures. It uses w/c ratio as

the predictive factor. Using this formula, one can predict the long-term strength gain

(i.e., beyond a 91-day curing period).

To improve the accuracy of Bhat's equation, the NCHRP study developed Equation

2-8. Equation 2-8 incorporates the following variables:

1. water/cement (w/c) ratio
2. aggregate type
3. fly ash type; and
4. fly ash content.

* Prediction equation for nonair-entrained mixture


S(t) = bg (t) (k ky ash ytypp )b2f (/c)b3(t) ()kWy ash content (2-8)


where bo(t) = -0.0007 t2 + 0.13 t- 0.76
bi(t)= -0.0001 -t2 + 0.013 t 0.42
b2(t) = -0.00008- t2 + 0.015 t 0.094
b3(t) = -0.003 t- 1.03
b4(t) = 0.75 0.018 then t_< 30 days
b4(t) = 0.22 when t > 30 days
S(t) = compressive strength (Mpa); and
t = age (days).

The critical aspect to the approach of the NCHRP model was to assign values to the

nonnumerical variables used in the formula. Through a trial-and-error process, the

following constants (k) were recommended for the materials used in the study's

investigation.

knver sand = 1.0

k foundry sand = 0.2
bottom ash 1.0
kcash = 2.2

kF ash = 1.0
kHC ash = 0.75









Constants are assigned to aggregate type, fly ash type, and fly ash content

variables. The empirical formula developed by the NCHRP study is an equation that is

readily available for one to use as a guide for designing flowable fill mixes. The formula

employs the variables that are of significance for predicting strength.

2.6 FDOT/UF Flowable Fill Study

A study titled "Use of Accelerated Flowable Fill in Pavement Section" was

conducted for the FDOT at the University of Florida (UF) investigating the usage of

flowable fills in the pavement section [39]. The objective of that study was to evaluate

performance of flowable fill in pavement sections using accelerated and nonaccelerated

mixtures. This evaluation included determination of strength, set time, and flow

applicable to conditions in Florida. The objective was accomplished by replicating

approved FDOT flowable fill mixtures in a laboratory setting. A comprehensive review

of the literature applicable to the research topics was conducted, followed by a survey of

municipalities and counties regarding the use of flowable fill. The unit weight, air

content, and compressive strength were analyzed to establish the conformity of the

contractor-provided mixes and those produced in the lab to FDOT specifications. A

relationship was revealed between the limerock-bearing ratio (LBR) and penetrometer

readings for different mix designs that will help measure the strength of underlying mix

in the field. Unit weights of the mixes depicted substantial variability amongst different

mix designs as well as amongst different districts within the same mix design. However,

a majority of the readings did not comply with FDOT specifications. Similar conclusions

were drawn for the air content of different mixes. The air content for a majority of the

districts were not within the FDOT specified range for both excavatable, as well as

nonexcavatable design mixes. The strength of the flowable fill mixture performance in









the laboratory and the strength obtained from collected samples of flowable fill from the

field were evaluated. For the mixtures that were replicated in the laboratory and field

samples being collected, the test yielded better insight and understanding of the

compressive strength of flowable fill at various curing times. The compressive strength

observed was typically above the FDOT specified range for excavatable mixes. For the

nonexcavatable mixes, the compressive strength complied with FDOT specifications,

however its value was considerably high. The relationship between LBR readings and

penetrometer readings was established through regression models. The models were

checked for adequacy.

The previous flowable fill research was successfully completed; however, further

research is necessary to yield a solution for producing flowable fill mixtures capable of

being reproduced and replicated with state DOT's specifications. This research will

concentrate on developing models for strength and shrinkage prediction, and will

establish a process, define procedures, and create guidelines for future flowable fill

mixtures.














CHAPTER 3
MATERIALS AND LABORATORY EXPERIMENTAL PROGRAM

3.1 Introduction

This chapter describes detailed information pertaining to the materials and experi-

mental design evaluated in this study. The method of preparation of the flowable fill

mixtures, design mix selection, mix proportions, fabrication of the test specimens and

testing procedures used in this study are also presented.

3.2 Experimental Design

The objective of this research was to evaluate flowable fill by varying mixture

components to help predict 28-day strength using prediction models. This involves using

excavatable flowable fill.

3.2.1 Rationale for Selecting Mixture Parameters

To meet the research objectives, mixture parameters with ranges were reviewed and

discussed. Particular interest was placed on evaluating parameters affecting flowable fill

strength. Table 3-1 shows the parameters (factors) selected for designing the laboratory

flowable fill mixtures.

A factorial design was employed to acquire insight into the effects of various

mixture parameters on LBR, compressive strength and shrinkage values of excavatable

flowable fill material. According to Montgomery [40], the purpose of a factorial design

is to study the effects of two or more factors. This is an experimental strategy in which

factors are varied together, instead of one at a time. In general, factorial designs are most

efficient for this type of experiment. By factorial design, we mean that in each complete









trial or replication of an experiment, all possible combinations of the levels of the factors

are investigated. For example, if there are a levels of factor A and b levels of factor B,

each replicate contains all ab treatment combinations. The mixture parameters, provided

in Table 3-1, include 4 factors. The factors are cement content, air content, mineral

admixtures, and water to cementitious (w/c) ratio. The laboratory study consists of a

4 x 3 x 2 x 3 factorial design. This design summed up to a total of 144 mixtures

including replicates.

Table 3-1. Mixture parameters
Mixture Parameters with Ranges
Cement content (4 levels): Air content (2 levels):
50 lb/yd3 7.5 % 2.5%
100 lb/yd3 17.5 % + 2.5%
50 lb/vd3
200 lb/yvd3
Mineral admixtures (3 levels): w/c ratio (3 levels):
No admixtures: 0% (1 level) 2.0
Fly ash class F: 20% (1 level) 4.5
Granulated ground blast furnace slag: 50% (1 level) 9.0
Slag: 50/50 or 50% slag and 50% Type I cement
Fly ash class F: 20/80 or 20% slag and 80% Type I cement

As seen in Table 3-1, the mineral admixtures factor is varied at three levels,

namely, 0%, 20% fly ash, and 50% slag. The 0% indicates a mix with no mineral

admixtures, 20% fly ash indicates a mix containing a 80% cement to 20% fly ash ratio,

and 50% slag indicates a 50% cement to 50% slag ratio.

Appendix A provides the full factorial design matrix along with tables showing the

design of flowable fill batch mix combinations for the experiments. The tables show the

order of the batches categorized into two experiments, Experiment 1 and Experiment 2.

Experiment 1 indicates the treatment combinations and Experiment 2 represents the

replicates. For each experiment, a total of 72 mixtures was generated.









The order in which the flowable fill was batched involves the use of numerical

randomization. According to Oehlert [41], randomization is one of the most important

elements of a well-designed experiment. Typically, the process of randomizing involves

the usage of numbers taken from a table of "random" numbers or generated by a

"random" number generator in computer software. The random numbers obtained for the

study were generated using computer software. The spreadsheet software used was

Microsoft Excel. Random numbers were generated for both experiments separately.

After the numbers were obtained for each batch, they were then sorted into increasing

order.

3.2.2 Mixture Proportioning

The design procedure used in this research project was based on the Absolute

Volume Method (SSD).

Steps in the mixture design calculations are:

1. Calculate absolute volume of cement in cubic feet per cubic yard (ft3/yd3) of
flowable fill.

C, = (3-1)
s, + 62.4

2. Calculate absolute volume of fly ash in ft3/yd3 of flowable fill.

F
100
(3-2)

F Fx 62.4
sf x 62.4









3. Calculate absolute volume of slag in ft3/yd3 of flowable fill.

S S
S -- x C
100
(3-3)

s, x 62.4

4. Calculate absolute volume of water in ft3/yd3 of flowable fill.

W =n (3-4)
62.4

5. Calculate absolute volume of air content in ft3/yd3 of flowable fill.

A, x 27
A, = (3-5)
100

6. Calculate absolute volume of saturated-surface-dry (SSD) for fine aggregate in
ft3/yd3 of flowable fill.

FA,, = 27 (C, + F, + + A,) (3-6)

7. Calculate weight of saturated-surface-dry in pounds per yard (lb/yd) of flowable
fill.

FA,,, = FA,, x Sag x 62.4 (3-7)

8. Calculate weight of fine aggregate base on natural moisture content in pounds per
cubic yard (lb/yd3 ) of flowable fill.

FAwn = FA, x 1 + N (3-8)
1 + L

9. Correct the weight of water due to percentage of moisture difference in lb/yd3 of
flowable fill.

AW = FA, FA
(3-9)
W= W +AW

where Cv = absolute volume of cement, ft3/yd3
Cw = weight of cement, lb/yd3









Sc = specific gravity of cement
Fw = weight of fly ash, lb/yd3
Fp = percent of fly ash by weight of cement
Fv = absolute volume of fly ash, ft3/yd3
Sf = specific gravity of fly ash
Sw = weight of slag, lb/yd3
Sp = percent of slag by weight of cement
Sv = absolute volume of slag, ft3/yd3
S, = specific gravity of slag
W, = absolute volume of actual water, ft3/yd3
Ww = weight of actual water, lb/yd3
A, = absolute volume of air, ft3/yd3
Ap = percent of air content
FAQ, = absolute volume of saturated-surface-dry fine aggregate, ft3/yd3
FAw, = weight of saturated-surface-dry fine aggregate, lb/ft3/yd3
Sag = specific gravity of aggregate
FAwn = weight of fine aggregate base on natural moisture content, lb/yd3
N = percent of natural moisture content
L = percent of absorption
AW = weight of water due to percentage of moisture different, lb/yd3;
and
W = water requirement, lb/yd3.

Typical computations are presented in Appendix A. Appendix A also provides

tables showing the volume computation results per combination of batch mix. The tables

provide computation results for both 1 yd3 and 5.5 ft3 mix volumes. A sand-to-water

ratio column is provided within the tables. The sand-to-water ratio was found beneficial

throughout the research for helping to determine whether a mixture is feasible or non-

feasible prior to mixing. Mixtures with a sand-to-water ratio range of 1.73 to 7.20 were

deemed feasible and those out of that range were classified as non-feasible.

This type of classification system was defined at the early stages of the research

study through trial mixing and from the early part of batch mixing. It was important to

see whether a mix was feasible or non-feasible for the purpose of time constraint.









3.2.3 Specimen Sample Collection per Batch Mix

The size and test samples to be collected from each batch are summarized below.

Table 3-2 summarizes the overall specimen samples required for each batch mix. As

shown, the total number of samples required for collection per mix is 33. The number of

samples needed per mix and the type of specimen samples (i.e., 18 LBR and 15 plastic

cylinder molds) helped determine the design of the experiment. The 33 samples collected

per mix provided the basis for total volume of flowable fill needed for each mix.

Table 3-2. Summary of sample specimens collected per mix
Curing Period No. of Samples (LBR) No. of Samples
(4-in. x 8-in. cylinders)
6 hrs 3 --
24 hrs 3 3
3 days 3 3
28 days 3 3
56 days 3 3
Oven cured, 2 days 3 --
Total 18 15 a
Number of samples per mixtures = 33
Volume of each LBR mold = 169.65 in3 = 0.10 ft3
Volume of each 4 x 8 cylinders = 100.53 in3 = 0.0582 ft3
Volume of each 6 x 12 cylinders = 339.29 in3 = 0.1963 ft3
Total volume required to fill samples per batch mix:
Volume = (18 x 169.65 + 12 x 100.53 + 3 x 339.29) in3
= 5277.93 in3 = 3.0544 ft3
aTotal includes three 6 x 12 cylinder samples produced for shrinkage testing.

Table 3-2 also shows the curing durations used for all the samples collected per

batch of mix. The volume of mix per batch was based on the total number of samples

needed per mix. As illustrated, an approximate volume of 3.0544 ft3 of flowable fill was

determined to be the required amount per batch of mix.

3.2.4 Specimen Molds

The specimen molds employed for the research can be categorized as cylindrical

LBR molds, either 4-in. x 8-in. or 6-in. x 12-in. test cylinders. The cylindrical LBR









molds were used to carry flowable fill samples for LBR testing. Eighteen LBR molds

were used in each batch mix. The mold samples were cured for varying periods: 6 hrs, 1

day, 2 days, 28 days, and 56 days. The test cylinders were of ASTM C 192-02 design.

3.2.5 Fabrication of Flowable Fill Specimens

Each mix required several steps to be undertaken before specimens could be

prepared. These are explained below.

3.2.5.1 Preparation of molds

The test cylinder molds and the circular molds were always prepared two days prior

to the start of the mix to be performed. The process of preparing for a mix required

proper cleaning of each LBR mold, and greasing them with mineral oil. The oil was used

to help prevent the molded sample from sticking to the molds, after casting the flowable

fill sample. This practice was necessary in order to promote best practice and to reuse the

molds after casting. A quarter-inch hole was drilled at the bottom end of each test

cylinder. This was done, in order to allow for drainage of water from specimen samples.

3.2.5.2 Mixing of flowable fill

All mixes were made during early morning hours. All flowable fill mixtures were

prepared using an 8-ft3 rotating concrete mixer with a 42-in. drum diameter. A picture of

the mixer is shown in Figure 3-1. The mixer is a 5.5-hp electric power mixer manu-

factured by Crown Equipment. The following procedures were followed:

* Two days prior to the start of each mix, all constituent materials (i.e., fine aggre-
gate, cement, fly ash, ground blast furnace slag) were carefully weighted and
placed into buckets with sealed lids. In addition, a 30-lb sample of fine aggregate
was obtained and placed into a moisture-drying oven to use for moisture correction.

* On the day of each mix, the moisture correction sample was removed from the
oven, weighted and the result used for making the moisture correction to the
weighted fine aggregates and water.




























Figure 3-1. Concrete mixer used in study

The watching sequence consisted of placing the sand into the mixer and making

sure that it was spread evenly inside the mixer. After the fine aggregate was placed into

the mixer, the mixer was turned on to homogenize the fine aggregate, then 80% of the

mixing water was added followed by the addition of cement, and any other dry materials

(i.e., fly ash, blast furnace slag). After placement of the dry materials into the mixer, the

mixer was kept rotating for three minutes, followed by a two-minute rest period. After

the rest period, the remaining mixing water was added along with any required air-

entraining admixtures (AEA). The mixing was resumed for three additional minutes. At

the end of the three minutes, a small sample of flowable fill was poured into a bin for

measuring the target air content (see Figure 3-2). The ASTM C 231 pressure method

procedure was used. After testing the air content, if the mix did not satisfy the target air

content, additional AEA would be added and the mix would be re-mixed for three

additional minutes. At the end of the three minutes, another air test would be performed

to check if the target air had been reached. This procedure would be repeated until the




























Figure 3-2. Pressure meter test for air content

target or acceptable level of air content was achieved. It was often found to be challeng-

ing to obtain both the desired air and water contents. For relatively dry flowable fill,

adding AEA would increase the air content. For mixtures that were very fluid or had

high flow, it was found to be very difficult to obtain 1 to 2% air content or air content

near the target. The experience gained from trial mixing allowed more efficient

converging to the target air content for each flowable fill mixture.

Immediately after mixing, flowable fill was poured into a large bin container for

transportation and subsequent transfer into specimen molds. Prior to pouring into

specimen molds, a sample of the fresh mix was taken so that other plastic property

measurements, such as unit weight, temperature, and flow tests could also be performed

on the mix. Each specimen mold was properly marked and labeled for identification and

testing purposes.









3.2.5.3 Casting of flowable fill

The casting of the specimen molds, shown in Figures 3-3 through 3-5, involved

placing them on a hard, flat and level surface. The surface used was a wooden palette.

Placing the specimens on a wooden palette allowed for the specimens to be easily

transported to a designated area for curing. Flowable fill was cast or poured into LBR

specimens without the need for compaction, as is normally needed for testing soils.

Casting the cylinder molds involved placing the flowable fill in equal layers. Each layer

was rodded and hand tapped to help release any trapped air. The same rodded and hand-

tapped procedure was also applied to the LBR specimens. After the sample was filled, it

was struck off with a tamping rod and the surface was troweled smooth. A plastic lid was

placed on top of the specimen molds while excess flowable fill material was washed off

the sides of the specimen and wooden palette. After specimens were collected, they were

transported to a safe area, to be cured at room temperature without disturbance.


Figure 3-3. Cast flowable fill in LBR samples
































Figure 3-4. Cast flowable fill in 4-in. x 8-in. compressivee strength) samples


Figure 3-5. Cast flowable fill in 6-in. x 12-in. (volume change) samples









The tests run on fresh flowable fill followed the ASTM standards shown in Table

2-1. These ASTM test methods are used primarily as a quality measure. Temperature of

the fresh flowable fill was determined in accordance with the ASTM C 1064 standard.

This test was used to ensure that the temperature of the fresh flowable fill was within

normal range and to ensure no unexpected conditions in the mix. A digital thermometer

was used to monitor mix temperature during plastic test.

The measured plastic properties for each flowable fill mixture are summarized in

Tables 3-3 and 3-4, shown below. The results of the mixtures are presented in the order

in which they were batched. As previously specified, the order of the mix is based on

their assigned random number. Note that mixtures marked with a superscript "a"

represent mixtures batched for a third time due to equipment malfunctions during

watching or testing. In Table 3-4 mixture numbers ending in "R" denote mixtures that

were replicated for statistical purposes; mixtures denoted with the term "Type I" are

mixes batched using ASTM Type I Portland cement.

3.3 Limerock Bearing Ratio Test (Florida Test Method 5-515)

The Limerock Bearing Ratio (LBR) test was adopted by the Florida Department of

Transportation (FDOT) as a standard strength test for subgrade and base materials in the

1960's [42]. The LBR test is a modified version of the California Bearing Ratio (CBR)

test. This test defines the ability of a soil to support a load. As part of this test, the

maximum density of the soil is determined by the standard ASTM D-1557 method. CBR

was renamed LBR because the standard strength for the CBR test was changed to more

closely represent Florida materials. Some minor procedural changes to the LBR test have

also evolved over the years. The LBR test, as used in flexible pavement design in

Florida, is a measure of the bearing capacity of soil. The test consists of measuring the











Table 3-3. Properties of fresh flowable fill (Experiment 1)

Batch Mix AEAa Flow Air Content (%) Unit Weight
XT 1T,1 11,/+ 3


4
25
15
23
50
16
61
34
24
59
58
51
69
26
40
16b
14
8
30
18
20
44
65
54
55
12
22
33
19
48
4b
69b
Note: aNR


um er (m) (m.)


NR 4.25
NR 0.00
NR 0.00
NR 0.00
100 5.25
1600 4.25
200 6.50
500 4.50
1000 0.00
1000 6.00
100 5.50
1000 10.50
200 7.00
500 4.00
200 7.00
500 7.00
10 0.00
250 5.00
500 0.00
25 0.00
500 0.00
75 5.50
75 8.00
25 0.00
500 7.00
25 0.00
25 0.00
25 0.00
500 9.00
175 6.75
25 0.00
25 4.25
= Not recorded


Target
7.5 + 2.5
7.5 + 2.5
7.5 2.5
7.5 2.5
17.5 2.5
7.5 2.5
17.5 2.5
7.5 2.5
7.5 2.5
17.5 2.5
17.5 2.5
17.5 2.5
17.5 2.5
7.5 2.5
17.5 2.5
7.5 2.5
7.5 2.5
7.5 2.5
7.5 2.5
7.5 2.5
7.5 2.5
17.5 2.5
17.5 2.5
17.5 2.5
17.5 2.5
7.5 2.5
7.5 2.5
7.5 2.5
7.5 2.5
17.5 2.5
7.5 2.5
17.5 2.5


Achieved
22.00
5.20
7.60
5.50
17.00
1.30
20.00
1.00
1.20
4.80
18.00
7.80
40.00
1.40
20.00
0.80
15.00
21.00
2.00
13.00
0.60
15.20
15.00
16.00
7.40
15.00
18.00
18.50
4.50
25.00
16.00
17.00


100.80
120.32
121.04
122.24
107.04
126.80
103.28
124.76
127.84
125.92
111.52
121.04
111.52
129.20
106.00
132.08
112.24
103.12
128.08
114.24
129.52
111.60
110.16
109.84
124.24
110.08
106.72
107.84
125.44
106.64
110.32
115.44


bmixtures batched for a third time due to malfunctions during watching or testing


Mixture
Temperature
(0o F)
68.00
68.40
70.00
69.00
76.00
71.00
70.00
70.00
70.00
72.00
73.00
76.00
71.00
72.00
70.00
72.00
72.00
78.00
71.00
70.00
72.00
79.00
76.00
78.00
78.00
78.00
77.00
73.10
73.20
73.00
71.00
70.50










Table 3-4. Properties of fresh flowable fill (Experiment 2)

Batch Mix AEAb Flow Air Content (%) Unit Mixture
Number (ml) (in.) Weight Temperature
Number (ml) (in.) Target Achieved (lb/t3) (0 F)


8R
16R
30R
18R
14R
22R
33R
23R
15-Type I
54-Type I
25-Type I
48-Type I
25R
34R
69R
26R
40R
19R
44R
48R
55R
54R
4R
58R
12R
15R
20R
65R
61R
59R
51R
24R
50R
25Rc
48Rc
55RC


250
500
500
NR
NR
NR
25
600
300
25
25
50
25
500
50
500
125
500
75
25
500
NR
25
75
25
550
500
75
150
1000
1000
1000
100
25
25
500


7.50
0.00
0.00
0.00
0.00
0.00
0.00
7.75
0.00
0.00
0.00
6.00
0.00
5.25
6.00
6.25
6.50
10.00
5.00
0.00
8.50
0.00
0.00
5.00
0.00
7.50
0.00
6.00
8.50
9.00
7.50
6.50
6.50
0.00
0.00
5.50


7.5 2.5
7.5 2.5
7.5 2.5
7.5 2.5
7.5 2.5
7.5 2.5
7.5 2.5
7.5 2.5
7.5 2.5
17.5 2.5
7.5 2.5
17.5 2.5
7.5 2.5
7.5 2.5
17.5 2.5
7.5 2.5
17.5 2.5
7.5 2.5
17.5 2.5
17.5 2.5
17.5 2.5
17.5 2.5
7.5 2.5
17.5 2.5
7.5 2.5
7.5 2.5
7.5 2.5
17.5 2.5
17.5 2.5
17.5 2.5
17.5 2.5
7.5 2.5
17.5 2.5
7.5 2.5
17.5 2.5
17.5 2.5


24.50
0.50
2.00
15.50
13.00
19.50
17.50
7.10
7.00
15.00
20.00
20.00
17.00
2.50
20.00
1.00
24.00
6.10
18.00
15.00
3.20
14.50
15.00
16.50
12.00
5.20
1.10
17.00
21.00
6.30
8.00
1.70
19.00
17.00
14.50
5.70


99.92
129.36
129.12
116.88
116.88
109.68
107.44
123.44
123.68
115.28
107.52
108.16
108.24
127.76
105.12
127.84
102.40
124.96
108.72
112.24
128.88
115.12
117.04
110.08
117.52
125.36
127.6
108.8
101.76
123.52
120.24
127.76
105.60
108.72
111.84
123.12


70.00
72.00
72.00
71.00
75.00
76.00
76.00
74.50
75.00
76.00
75.00
75.00
75.00
75.00
74.00
75.00
79.00
74.50
78.00
75.00
75.00
75.50
75.00
74.50
75.00
75.00
75.00
75.00
76.00
78.00
71.00
69.00
70.00
70.00
80.00
75.00


Note: aR in mixture number = mixtures that were replicated for statistical purposes; Type I in
mixture number = mixes batched using ASTM Type I Portland cement
bNR = Not recorded
Mixtures batched for a third time due to malfunctions during watching or testing










load required to cause a standard circular plunger (an area of 3 in2) to penetrate the soil

specimen at a specified rate (refer to Figures 3-6 and 3-7). The specifications for the

LBR test equipment are included in Table 3-5. The LBR test measures the unit load (in

lb/in2) required to force the plunger into the soil 0.1 in., expressed as a percentage of the

unit load in lb/in2, required to force the same plunger to the same depth in a standard

sample of crushed limerock.


10-lb seating load


Surcharge weights
(as required)


No. 4, 15-cm
filter paper _


.001 in. indicating dial
measuring penetration







Mold 6 in. internal dia.






Soil sample
- 6 in. dia. x 4.59 in. high


Figure 3-6. Cross section of seated LBR penetration piston [42]












































Figure 3-7. LBR machine


Table 3-5. Specifications for LBR test equipment


Equipment


Specifications


LBR Press


LBR Recording Device


System Calibration Device


Rainhart Company, Model 762
Rate of loading: .050 in./minute
Load cell capacity: 10,000 lbs

GPE, Inc., Model DMP-12A
Digital LBR readout
Proprietary plot program
RS 232 communications port
Download to computer: Windows XP

Steel spring soil simulator at 100 LBR +5 LBR









The average penetration unit load for a typical crushed limerock found in Florida

has been standardized to 800 lb/in2. The resulting ratio multiplied by 100 is known as the

Limerock Bearing Ratio (with percentage omitted). The test results are intended to

provide the relative bearing value of base and stabilized materials [42].

Samples are tested by penetrating the specimens. This is accomplished with an

automatic compression device equipped with a load measuring system. A typical test is

shown and the penetration curve is plotted in Figures 3-8 and 3-9, respectively. The

corrected unit load obtained at 0.1-inch penetration is divided by 800 lb/in2, the standard

strength of limerock. This ratio is then multiplied by 100, and the resulting value is the

LBR in percent, as shown in equation below.


LBR = Corrected Unit Load (3-0)
800

The load penetration relationship curve will usually be convex upwards although

the initial portion of the curve may be concave upwards. The concavity is assumed to be

due to surface irregularities (Figure 3-9). A correction is applied by drawing a tangent to

the curve at the point of greatest slope. The corrected curve then becomes the tangent

plus the convex portion of the original curve with the origin moved to the point where the

tangent intersects the horizontal axis. Methods of correcting typical curves are illustrated

in Figures 3-8 and 3-9.

3.4 Compressive Strength Test

Although there is an existing standard method for measuring the unconfined

compressive strength of flowable fill (ASTM D 4832), a different method was utilized for

this research. Compressive strength tests were performed according to ASTM method

D-2166-00 (AASHTO T 208-05). This test covers the determination of the unconfined






61



1600 i --

|,00o -------------. ----------'- ------






1200




c 1000
Unit Load at 0.1 Inch
Penetration -
c 800 lbs/in


LBR = x 100 100%


f 600
C



4oo




200

S No Correction Required


0 0.1 0.2 0.3 0.4 0.5
Penetration (in.)


Figure 3-8. Graph example showing typical load penetration curve that requires no
correction [42]










1600


1200


1COo




800




600


0 0.1


Figure 3-9. Graph example showing correction of typical load penetration curve for
small surface irregularities [42]


Penetration (in.)









compressive strength of cohesive soil in the undisturbed, remolded, or compacted

condition, using strain-controlled application of the axial load. The test method provides

an approximate value of the strength of cohesive soils in terms of total stresses. The

method of testing was selected due to the low strength of flowable fill and the

resemblance of its properties to cohesive soils. The compression tests were performed

using a computerized testing machine with a relatively low-load capacity machine with

displacement control. For this research the compression machine used was equipped

with a 2000-lb load cell. The apparent strain rate was set at 0.015 inches per minute.

The linear voltage displacement transducer (LVDT) used was a 2-inch MPE type HS.

The load frame was a 5-ton compression machine, manufactured by Wykeham Farrance.

Figure 3-10 shows the set up for the compressive strength test. The compressive strength

of the test specimen is calculated by dividing the maximum load attained from the test by

the cross-sectional area of the specimen.


Figure 3-10. Typical set-up for compressive strength test









Before testing the flowable fill specimen, it was removed from its plastic cylinder

mold. Removing the specimen from the mold involved careful handling due to its low

strength (as compared to hardened concrete cylinders). The cylinders were cut length-

wise, using a box cutter. Specimens were kept in molds until the day of testing.

3.5 Proctor Penetrometer Test

Penetration resistance of the LBR mold specimens were obtained using the proctor

penetrometer testing method outlined in ASTM D 1558-99. In this test, a cylindrical

needle tip is pressed one inch into the flowable fill at a constant rate, and the resistance

offered by the flowable fill is measured in pounds. This value (in pounds) is divided by

the cross sectional area of the tip in square inches, and is taken as the penetration

resistance in pounds per square inch (psi). Since different needle tip diameters exist, the

choice of needles selected depended on the strength of the material being tested. Figure

3-11, shown below, depicts the proctor penetrometer device in its carrying case with a

complete set of penetrometer needles. The needles have end areas of 1 in2, 3/4 in2, 1/2

in2, 1/3 in2, 1/5 in2, 1/10 in2, 1/20 in2, 1/30 in2, and 1/40 in2. The psi values obtained


Figure 3-11. Typical proctor penetrometer









from the proctor penetrometer are not equivalent to the psi values obtained from

unconfined compressive strength tests.

3.6 Drying Oven

A standard laboratory oven with approximately 6 ft3 of capacity was used for

curing of oven specimen samples. LBR samples were stored inside the oven at a set

temperature of 1100 F. The oven is equipped with a thermostat and sensor to control the

temperature of the oven. Prior to the start of every mix, the oven was turned on to ensure

that it would be warm enough to place specimens inside. Information acquired from

specimens cured in the oven would help predict in-service aging.

3.7 Drying Shrinkage of Flowable Fill Mixtures

For each flowable fill mixture batched, three 6-in. x 12-in. cylinders were made to

evaluate its shrinkage behavior due to volume change. The cylinders were cured under

normal conditions.

Currently, no standard test methods exist for the measurement of drying shrinkage

in flowable fill. As a result, a review of published studies was done to identify standard

methods of testing of drying shrinkage in flowable fill. Most of the published studies

reviewed showed the use of the conventional concrete method to measure shrinkage of

flowable fill specimens (7). This method specifies embedding gage studs at both ends of

a specimen and measuring the length change. Careful handling of the shrinkage prisms

during form removal and subsequent measurements is required. Flowable fill specimens

could be damaged when using this approach because of the lower strengths of flowable

fill. Thus, this approach may not be appropriate for flowable fill. Another approach

found for measuring shrinkage in flowable fill was used by Lutcht (43). In his study,









Lutcht used the shrinkage ring method to measure shrinkage in flowable fill. Typically, a

shrinkage ring is used to measure the cracking of concrete cast around a steel ring. The

approach utilized by Lutcht is not an adopted standard and thus represents 100% restraint

and is used for assessing different materials and mixtures. Using the knowledge gained

from other research studies, various attempts and methods were devised to measure the

volume change that occurs in flowable fill.

3.7.1 Method 1

The first method used to measure the drying shrinkage in flowable fill was

somewhat similar to the ASTM C157 standards used for measuring drying free shrinkage

in concrete. ASTM C157 standards call for using square prism specimen molds with

dimensions of 3 x 3 x 11.25 inches. All of procedures of the ASTM C157 standards

were followed, with the exception of the specimen molds. Instead of using square prism

molds, 6-in. x 12-in. cylinders were used.

The amount of shrinkage was measured with a linear voltage displacement

transducer (LVDT) of an accuracy of 0.00039 in., which measured displacement. The

LVDTs used for this project were made of AISI 400 series stainless steel. They are

complete and ready-to-use displacement transducers with a sleeve bearing structure on

one end that supports a spring-loaded shaft attached to the core. The bearing is threaded

externally to facilitate mounting. By using a spring loaded LVDT, the need for core rods

or core support structures is eliminated. All LVDTs are hermetically sealed to operate in

harsh environments such as a moist room and have an operating temperature range of

0 F to 1600 F (-17.80 C to 71.1 C) to facilitate testing of temperature effects.










The data acquisition system used was an Agilent 34970A unit (by Agilent

Technologies) with a HP 34901A (20-channel armature multiplexer) plug-in module.

The data acquisition unit can be set up to take readings at specified time intervals and for

a specified length of time. The HP 34901A multiplexer module can read up to 20

channels of AC or DC voltages with a maximum capacity of 300 V. It has a switching

speed of up to 60 channels per second. It also has a built-in thermocouple reference

junction for use in temperature measurement by means of thermocouples. Thus, the

Agilent 34970A data acquisition unit with one HP 34901A multiplexer module will be

adequate for the job of recording load and displacement readings from ten testing

apparatuses. The Agilent 34970A unit can take up to three plug-in modules. Thus, if

needed, it can be expanded to take up to 60 channels of output.

The test setup for measuring the free shrinkage using LVDT is shown in Figures

3-12 and 3-13. Figure 3-12 is a photograph of several test set-ups that were used,

simultaneously, while Figure 3-13 is the schematic of these test set-ups. Three sets of

measurements were taken from each specimen. A total of nine sets of measurements

were taken from the three replicate specimens for each flowable fill mixture. Shrinkage

measurements were taken at 1-, 3-, and 7-day intervals.

The setup for the ASTM C 157 free shrinkage test consisted of a DC-powered

LVDT connected to a shrinkage test frame that held the specimen. The output from the

LVDT was connected to a Data Acquisition System (DAS). A laptop computer was used

to download the data from the DAS. The data downloaded from the Data Acquisition

System was in readable form with Microsoft Excel "Comma Separated Variable" format.







68































Figure 3-12. Test set-up for measuring shrinkage using LVDTs


CF-fpltr

/-i Plug-in-Modules
DAI ----


Specimens Specimens Specimens


Figure 3-13. Schematic of test set-up for measuring shrinkage using LVDTs


LVDT









3.7.2 Method 2

The second method for measuring drying shrinkage in the flowable fill specimen

utilized a dial gauge. The process involved filling the cylinder mold with flowable fill,

finishing the surface, and then leveling it off with the cylinder top. This provided a 12-in.

gauge length and 0.000-in. initial reading. When the readings were taken, the plunger of

the dial gauge was placed in the center of the cylinder and then lowered until the bridge

set on top of the cylinder mold. A total of three readings were taken at 1-, 4-, and 7-day

intervals.

Figures 3-14 and 3-15 provide images of flowable fill specimen cylinders with the

gauge being used. For this method, the gauge is used to measure the change in the

specimen height which occurs as the flowable fill specimen volume changes or shrinks

(final height, hf, of flowable fill specimen). The dial gauge used has an accuracy reading























Figure 3-14. Three-dial gauge reading method (gauge placed on level flowable fill
surface)

























Figure 3-15. Dial gauge shrinkage reading being taken


of 0.00039 inch. After the final height of the flowable fill specimens was taken, the

results were used to compute the percent volume change by using Equation 3-11,


% volume change = x 100 (3-11)


where h, = initial specimen height
hf = final specimen height
V, = initial volume
V, = area of specimen x initial height of specimen = rr2 x h,
Vf = final volume
Vf = area of specimen x final height of specimen = 7r2 x hf

3.7.3 Method 3

The third method used for measuring shrinkage involves measuring the height

difference of the 4-in. x 8-in. specimens. This method is more straightforward than the

previous two and not much lab work is involved. The height difference is measured by

subtracting the final specimen height (hf) from the initial specimen height (h,), as shown

in the equation below.


Ah = h, h(


(3-12)









The final specimen height was measured after the flowable fill specimens were cured for

24 hours and demolded from the plastic cylinders.

3.8 Materials

This section details information about the materials that were used in the

preparation of mixes in the laboratory for this study. The materials used were adequately

tested to ensure that they conformed to their manufacturer's specifications.

3.8.1 Cement

The cement used was Type I/II and Type I Portland cement. The Type I/II Portland

cement is manufactured by Florida Rock Company. The Type I cement is manufactured

by Rinker Materials. Chemical and physical analyses of cements were conducted by

FDOT State Materials personnel. The results can be seen in Tables 3-6 and 3-7. The

cements procured met the specifications for Type I cement as given by C-1 14, C-109,

C-151, C-187, C-204, and C-266.

Table 3-6. Chemical composition of cement used

Portland Cement Type
Chemical Composition
I I/II
(%) (%)
Loss of ignition (LOI) 1.40 1.90
Insoluble residue 0.13 0.40
Sulfur trioxide (SO3) 2.59 2.60
Magnesium oxide (MgO) 2.01 0.60
Tricalcium aluminate (Ca3Al) 4.02 7.00
Total alkali as (Na20) 0.29 0.28
Silicon dioxide (SiO2) 20.91 21.20
Aluminum oxide (A1202 4.08 5.10
Ferric oxide (Fe203) 4.01 3.80
Tricalcium silicate (Ca3Si2) 62.29 50.00









Table 3-7. Physical characteristics of cement
Compressive Strength Setting Time
e Average (psi) Fineness (Gilmore) (minutes) Soundness Normal
(m2/kg) Autoclave Consistency
3 Days 7 Days Initial Final

I 3310 4280 397 159 205 +0.03% -
I/I 2720 3820 410 145 200 2720 3820

Table 3-6 provides the results of chemical analysis on the Portland cement used for

the mixtures. According to the analysis, all cement met FDOT specifications passing the

required chemical analysis tests in order to be considered for use in FDOT concrete mix.

3.8.2 Fly Ash

Strength of flowable fill can be improved by adding fly ash to the mixture. The fly

ash acts to improve workability, and is a cementing agent that improves long-term

strength. The silica glass in fly ash reacts with the free lime liberated during hydration of

Portland cement to form a more stable cementing compound [44].

Fly ash was procured in a manner similar to that of cement. Class F fly ash was

acquired from different manufacturers, which included JTM and others. The testing

performed on the fly ash conforms to the required specifications for fly ash as given by

C-114 and C-311 (see Table 3-8 for results). The Class F fly ash used had a unique color,

light gray, very close to that of silica fume.

3.8.3 Blast Furnace Slag

Ground blast furnace slag (ASTM C 989) was procured in a manner similar to the

fly ash. Chemical and physical analyses were carried out by FDOT State Materials per-

sonnel (see results in Table 3-9). Samples conformed to required specifications C-989,

C-114, C-109, and C-430.










Table 3-8. Chemical and physical analyses of fly ash
ASTM C 618
Parameter Value ASTM C 618
Class F Specifications
Chemical Analysis:
Sum of SiO2, A1203, & Fe203, % 84.20 min 70.0
Sulfur trioxide (SO3), % 1.00 max 5.0
Moisture content, % 0.10 max 3.0
Loss on ignition, % 4.90 max 6.0
Alkalis as Na20 equivalent, % max 1.5
Calcium oxide (CaO), % -
Physical Analysis:
Fineness, amount retained on No. 325 sieve, % 29.00 max 34
Strength activity index-7 days, % 66.00 min 75
Strength activity index-28 days, % 81.00 min 75
Water requirement, % 98.00 max 105

Table 3-9. Chemical and physical analyses of blast furnace slag

Parameter Value ASTM C 989
Grade 100 Specifications
Chemical analysis:
Sulfide sulfur (S), % 0.60 max 2.5
Sulfate ion reported as SO3, % 1.60 max 4.0
Physical analysis:
Fineness, amount retained on No. 325 sieve, % 5.00 max 20
Air content, % max 12
Slag activity index-7 days, % 108.00 min 90
Slag activity index-28 days, % 142.00 min 110
Specific gravity 2.92 NA

3.8.4 Aggregates

Procurement of aggregates was done in a manner similar to that of the cement.

Table 3-10 provides information concerning the location where fine aggregates were

obtained. The fine aggregate used was silica sand. Throughout the study, two loads of

sand were used. The first load is designated as sand #1 and the second load as sand #2.









Table 3-10. Fine aggregate location source
Fine Aggregate Type Representative FDOT Approved Aggregate Location
FDOT District Source Pit No.
Silica sand 2 76-349 Melrose, Florida

Both loads came from the same sand mine. Tests on the aggregates were

performed according to ASTM and FDOT specifications. The type of tests performed

included the colorimetric and gradation tests. The colorimetric test was carried out to

provide information on whether the aggregates contain impurities [21]. The tests were

conducted in accordance to AASHTO T21 and AASHTO T71. Impurities interfere with

the process of hydration of cement; coatings would prevent the development of a good

bond between aggregate and the hydrated cement paste as well as other individual

particles which are weak.

The silica sand used in this study varied in color from light gray to sandy white. As

specified by FDOT, the silica sands used were composed of naturally occurring hard,

strong, durable, uncoated grains of quartz and graded from coarse to fine. This type of

sand is the same used for concrete mixes.

3.8.4.1 Aggregate gradation

Gradation is perhaps the most important property of an aggregate. It affects almost

all the important properties for a mix, including the relative aggregate proportions, as

well as the cement and water requirements, workability, pumpability, economy, porosity,

shrinkage, and durability. Therefore, gradation is a primary concern in concrete/flowable

fill mix design. Aggregate gradation is the distribution of particle sizes expressed as a

percent of the total weight. The gradation as a percent of the total volume is also

important, but expressing gradation as a percent by weight is much easier and is a

standard practice. Gradation analyses were performed on all fine aggregates used for all









the mixtures created. The gradation was then compared using the ASTM and FDOT's

upper limit (UL) and lower limit (LL) sieve analysis for fine aggregate as shown below in

Table 3-11. ASTM and FDOT upper/lower limits shall be graded within the limits

indicated in Table 3-11.

Table 3-11. ASTM C33-02A and FDOT specifications for fine aggregate gradation
Percent Passing
Sieve Sizes
ASTM C33 FDOT
9.50 mm (3/8 in.) 100 100
4.75 mm (No. 4) 95 to 100 95 to 100
2.36 mm (No. 8) 80 to 100 85 to 100
1.18 mm (No. 16) 50to 85 65 to 97
600 pm (No. 30) 25 to 60 25 to 70
300 pm (No. 50) 5 to 30 5 to 35
75 pm (No. 200) 0 to 10 4

Figure 3-16 illustrates the upper and lower limits of the ASTM C33-02A gradation

for fine aggregates. Figure 3-17 shows the gradation for fine aggregates in accordance

with the FDOT fine aggregates specification. Unlike the ASTM C33-02A higher sieve


2
Sieve Sizes (mm)


0.25


-*--ASTM LL -m-ASTM UL ---sand #1 -*-sand #2


Figure 3-16. Gradation of fine aggregates-ASTM specs










100 ,.,

S80
70_ _
'* 60- V--
C 50- -__-
4 40-
30 -
20
10

19.1 9.5 2 0.25
Sieve Sizes (mm)

-- -FDOT- LL -u- FDOT- UL -a--sand #1 --sand #2


Figure 3-17. Gradation of fine aggregates-FDOT specs


gradation boundaries, the FDOT higher sieve gradation boundaries allow for both loads

of sand to fall within the required specification gradation limits. Table 3-11 gives fine

aggregate gradation variation that starts from sieve no. 16 down to sieve no. 200 between

ASTM C33-02A and Florida specification.

3.8.4.2 Physical properties, absorption and moisture content

The physical properties for the aggregates were provided by FDOT State Materials

Geotechnical Laboratory. The physical properties for these aggregates are summarized in

Table 3-12.

Table 3-12. Physical properties of fine aggregates (silica sand)
Sand #1 Sand #2

Fineness modulus 2.23 2.05
Dry bulk specific gravity 2.63 2.62
Bulk specific gravity (SSD) 2.64 2.63
Apparent specific gravity 2.65 2.65
Absorption 0.44
- = No data available









Absorption is defined as the amount of water retained within the pores of the coarse

or fine aggregate after saturation and removal of the excess surface moisture. The

aggregates were maintained in a saturated condition and the moisture content of the

aggregates were determined regularly before casting, using ASTM C 566-97. The

aggregate absorption was subtracted from the moisture content to yield the surface

moisture, which was counted as part of the mixing water for the design mix. The actual

weights of the wet aggregates and water used were determined using Equation 3-9.

3.8.4.3 Storage of fine aggregates

As fine aggregates were obtained from their aggregate source location, they were

brought to the lab facility where mix was prepared and stored in an area designated for

aggregate storage. The photograph shown in Figure 3-18 depicts the area where the fine

aggregates were stored prior to being used in a mix.


Figure 3-18. Storage and removal of fine aggregates









3.8.5 Admixtures

The admixtures used were air-entraining admixture (AEA). It is classified as a

Darex AEA, and manufactured by W.R. Grace & Co. Darex AEA is a liquid used as an

air-entraining admixture, providing freeze/thaw durability. It contains a catalyst used for

forming a rapid and complete hydration of Portland cement. As it imparts workability

into the mix, Darex AEA is particularly effective with slag, lightweight, or manufactured

aggregates. The AEA used meets all the requirements of ASTM C494.

3.8.6 Water

According to Kosmatka and Panarese, the presence of excessive impurities in

mixing water is known to affect strength and durability of Portland cement concrete (44).

It is believed that concrete and other cementitious mixtures containing mixing water

having high levels of impurities may impact strength development. In this study, potable

water is used as mixing water for production of the flowable fill mixtures.














CHAPTER 4
LABORATORY RESULTS AND DISCUSSIONS

4.1 Introduction

This chapter presents the laboratory results of the flowable fill mixtures. The

laboratory tests were conducted at the Florida Department of Transportation State

Materials Office in Gainesville, Florida. Detailed discussions on the results are included,

along with influencing strength factors affecting the long-term behavior of flowable fill.

In Chapter 5, a comprehensive statistical analysis of all data is discussed.

4.2 Laboratory Results

4.2.1 Limerock Bearing Ratio (LBR)

Tables 4-1 and 4-2 provide the LBR results for the mixtures performed in the

laboratory for Experiments 1 and 2. LBR results are shown for 6-hour, 1-, 3-, 28- and

56-day durations. The data shown were found to be repeatable in comparison to their low

coefficient of variation values. From the tables it can be seen that no clear pattern exists

among the individual batch mixes. Statistical analyses of the LBR results are presented

in Chapter 5.

4.2.2 Compressive Strength (psi)

The compressive strength results along with mixture proportions are shown in

Tables 4-3 and 4-4 for each laboratory experiment. Strength results are provided for 1-,

3-, 28- and 56-day durations. Like the LBR data, the compressive strength results were

found to be repeatable. The coefficients of variation for data obtained for both

experiments range from 0% to 45.69%.











Table 4-1. LBR strength results for Experiment #1
Batch 6-hr Coeff. 1-day Coeff. 3-day Coeff. 28-day Coeff. 56-day Coeff.
Mix Strength ofVar. Strength ofVar. Strength ofVar. Strength ofVar. Strength ofVar.


Number (LBR) (%)
4 0 --
25 1 0.00
15 1 0.00
23 3 0.00
50 0 --
16 0 --
61 0 --
34 1 0.00
24 1 0.00
59 0 --
58 0 --
51 0 --
69 0 --
26 1 0.00
40 1 0.00
16a 2 0.00
14 1 0.00
8 1 0.00
30 1 0.00
18 1 0.00
20 1 0.00
44 1 0.00
65 0 --
54 1 0.00
55 0 --
12 2 0.00
22 1 0.00
33 1 0.00
19 1 11.93
48 0 --
4a 1 0.00
69a 1 0.00


(LBR) (%) (LBR)
1 0.00 10
6 39.74 15
22 47.24 37
14 4.23 34
4 15.75 10
33 5.25 75
1 0.00 3
5 47.30 18
14 21.43 28
10 31.11 31
2 49.49 12
28 32.79 35
8 24.98 1
7 37.80 25
23 11.27 42
32 0.00 53
13 11.15 28
17 8.81 39
13 12.00 24
8 24.98 21
24 18.79 55
18 3.15 38
2 0.00 3
7 7.87 18
21 42.01 43
14 8.45 44
4 25.00 12
3 17.32 5
20 12.80 31
6 16.67 35
20 17.27 49
2 0.00 6


(%) (LBR) (%) (LBR)
11.18 52 7.72 49
20.96 45 33.68 70
19.49 140 12.88 200
21.86 148 6.01 223
11.18 56 14.17 62
4.81 242 16.36 337
0.00 17 9.09 15
33.71 103 15.59 117
8.15 190 13.03 266
38.21 230 33.90 270
9.36 77 32.21 81
9.27 219 44.51 190
0.00 6 18.23 6
0.00 110 14.25 126
7.48 142 9.82 118
9.74 281 11.95 223
18.91 90 14.76 80
2.56 120 4.41 123
23.37 67 14.88 110
22.15 81 9.30 99
29.22 131 30.27 192
4.56 112 5.06 142
33.33 12 9.90 16
5.56 36 30.24 73
32.81 123 20.74 220
30.29 188 7.16 237
9.36 60 8.27 81
20.00 21 20.76 31
11.45 111 3.74 198
11.66 173 30.65 173
1.19 192 24.02 168
20.38 32 8.27 35


Note: mixtures batched for a third time due to malfunctions during watching or testing


(%)
10.80
14.50
19.03
32.88
6.14
13.50
35.28
11.35
22.89
23.76
6.12
4.56
9.12
8.83
2.07
4.35
16.56
7.79
26.83
13.14
4.45
8.14
16.54
28.68
29.16
4.66
14.48
10.48
34.18
17.67
2.98
6.54










Table 4-2. LBR strength results for Experiment #2
Batch 6-hr Coeff. 1-day Coeff. 3-day Coeff. 28-day Coeff. 56-day Coeff.
Mix Strength ofVar. Strength ofVar. Strength ofVar. Strength ofVar. Strength ofVar.
Number (LBR) (%) (LBR) (%) (LBR) (%) (LBR) (%) (LBR) (%)


8r
16r
30r
18r
14r
22r
33r
23r
15-Type I
54-Type I
25-Type I
48-Type I
25r
34r
69r
26r
40r
19r
44r
48r
55r
54r
4r
58r
12r
15r
20r
65r
61r
59r
51r
24r
50r
25r
48r
55r


-- 8
-- 45
0.00 10
0.00 8
0.00 9
0.00 7
5.06 3
0.00 13
33.30 36
34.60 10
0.00 6
-- 17
0.00 5
-- 12
-- 2
0.00 23
0.00 23
2.47 24
19.38 32
0.00 28
0.00 18
0.00 16
0.00 39
-- 3
21.65 23
0.00 29
0.00 35
-- 3
-- 2
-- 9
0.00 18
-- 12
-- 4
0.00 4
0.00 15
-- 15


15.06
15.73
24.35
37.65
22.30
14.29
43.30
26.65
9.67
5.59
9.12
6.66
12.37
13.09
34.64
21.57
15.49
12.20
6.25
16.30
24.60
9.35
16.81
17.32
12.74
10.07
26.21
43.30
34.64
16.37
19.25
17.84
25.00
13.32
10.42
16.41


10.66
14.18
18.65
28.20
31.77
4.56
17.32
4.88
4.09
1.82
10.83
8.54
14.78
34.51
15.75
37.40
6.52
13.56
16.15
2.86
17.77
9.93
19.04
9.90
16.15
25.08
16.21
12.37
33.00
18.23
8.17
14.32
8.66
27.71
9.93
12.61


58
268
55
40
50
53
34
156
145
57
30
173
26
87
15
101
121
117
161
254
164
52
202
42
242
184
143
16
12
151
181
207
42
19
225
158


21.96
27.11
15.56
6.61
30.54
9.44
7.29
8.52
5.39
3.51
10.07
1.33
15.75
13.37
13.33
39.46
8.63
12.64
4.03
3.16
9.86
17.13
26.41
4.12
12.20
1.96
32.23
16.54
24.74
24.43
13.61
9.55
11.84
19.58
5.64
5.87


2.26
26.18
2.87
19.97
24.05
4.68
10.54
15.08
18.02
11.73
6.57
2.90
7.61
12.70
10.66
20.09
14.84
10.67
1.19
2.36
8.64
3.09
25.66
7.92
14.31
6.39
23.94
0.00
26.06
20.89
16.82
32.01
9.66
8.09
10.51
29.93


Note: r = mixtures that were replicated for statistical purposes; and
Type I = mixtures batched using ASTM Type I Portland cement
mixtures batched for a third time due to malfunctions during watching or testing











Table 4-3. Compressive strength results for Experiment #1
Batch 1-day Coeff. 3-day Coeff. 28-day Coeff. 56-day Coeff.
Mix Strength ofVar. Strength of Var. Strength of Var. Strength of Var.
Number (psi) (%) (psi) (%) (psi) (%) (psi) (%)
4 2 7.90 6 21.19 50 4.23 41 14.69
25 2 0.00 4 24.06 17 15.90 29 5.15
15 4 1.43 13 22.87 58 3.93 93 10.18
23 2 6.38 11 3.81 80 19.56 124 7.74
50 3 4.82 7 7.05 45 9.39 39 3.34
16 6 0.00 19 1.31 89 13.49 133 10.01
61 1 0.00 2 10.59 14 16.26 17 26.19
34 2 3.27 3 35.25 30 14.55 44 9.25
24 2 4.35 8 25.75 79 23.01 155 9.28
59 2 7.16 9 19.32 89 9.03 111 9.02
58 1 3.94 6 6.13 66 5.73 72 6.62
51 2 5.59 15 18.63 67 12.98 108 17.85
69 1 0.00 1 17.84 9 17.78 8 18.39
26 2 0.00 7 0.00 22 0.00 34 15.17
40 10 2.67 32 3.29 138 7.42 114 9.67
16 a 6 0.00 12 0.00 70 7.96 148 7.58
14 2 18.18 8 15.02 58 16.72 69 15.08
8 8 12.08 32 4.76 100 13.40 129 6.02
30 1 18.41 1 0.00 14 22.57 34 18.22
18 2 20.00 5 12.92 33 15.45 43 7.36
20 4 13.12 11 15.84 86 21.76 132 43.98
44 5 25.56 22 5.48 107 1.16 114 9.67
65 1 0.00 1 0.00 3 20.03 8 18.97
54 3 28.67 6 21.31 39 3.80 46 11.64
55 4 7.28 10 0.00 81 2.60 81 38.04
12 13 36.82 34 8.28 143 10.79 139 5.99
22 4 16.22 7 15.15 42 9.38 37 11.47
33 1 15.75 2 27.78 13 11.44 15 14.48
19 5 31.66 16 13.60 56 15.92 132 43.98
48 9 7.84 40 17.95 109 11.96 135 7.77
4a 14 12.70 34 3.25 115 4.09 105 14.86
69a 1 0.00 4 10.26 19 7.77 24 10.88
Note: mixtures batched for a third time due to malfunctions during watching or testing