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Evaluating Limerock-Base Thick Lift


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EVALUATING LIMEROCK-BASE THICK LIFT By JEONGSOO KO A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLOR IDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF ENGINEERING UNIVERSITY OF FLORIDA 2005

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Copyright 2005 by Jeongsoo Ko

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To my family, especially my lovely wife.

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iv ACKNOWLEDGMENTS I would like to express my sincere gratitude to Dr. Michael C. McVay for the opportunity to do this project and for my i nvaluable guidance during the research. I also wish to express my thanks to Dr. Frank C. Townsend and Dr. Bjorn Birgisson for teaching the basic concept on which my study is based. I appreciate their time and efforts they devoted to serving on my supervisory committee. I also wish to express my gratitude to Dr. Putcha of the FDOT for his financial support. For supporting installation and measurin g of soil properties, I also thank to Mr. Werner of Ardaman & Associates, Orlando, FL and the Florida State Materials Office. I deeply appreciate the interest and overall support received from Mr. Tim Relke from District 2 and Mr. Jack Banning. I thank the geotechnical group of the Civil and Coastal Engineering Department, at the University of Florida. I would like to say thank Scott for his help for recommending this project and for my friendship with Zihong and Lila. Finally, I thank my wife, Yookyeong for her patience, encouragement, and sacrifice for 2 years of my graduate study, and I thank my family for their endless love and support.

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v TABLE OF CONTENTS page ACKNOWLEDGMENTS.................................................................................................ivLIST OF TABLES............................................................................................................viiLIST OF FIGURES...........................................................................................................ixABSTRACT......................................................................................................................x ii CHAPTER 1 INTRODUCTION........................................................................................................11.1 General.................................................................................................................... 11.2 Objective.................................................................................................................21.3 Scope...................................................................................................................... .31.3.1 Task 1...........................................................................................................31.3.2 Task 2...........................................................................................................41.3.3 Task 3...........................................................................................................42 COMPACTION BACKGROUND...............................................................................52.1 Field Vibratory Compaction...................................................................................52.2 Strength, Moisture and Compactive Effort.............................................................62.3 Intelligent Compaction.........................................................................................103 TEST SITE AND INSTRUMENTATION................................................................143.1 Materials, Site Layout, and Equipment................................................................143.2 Embedded Instrumentation...................................................................................153.2.1 Accelerometers...........................................................................................173.2.2 LVDT.........................................................................................................183.2.3 Stress Cell...................................................................................................184 RESULTS AND DISCUSSION.................................................................................204.1 Stress Measurements............................................................................................204.2 Compactive Energy vs. Depth..............................................................................224.3 LVDT Strains & Measured Densities...................................................................264.4 Measured Dry Densities and Moistures vs. FDOT Specified Values..................30

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vi 4.5 Base Stiffness........................................................................................................334.6 Base Strength vs. Depth........................................................................................385 SUMMARY, CONCLUSION AND CONCLUSIION..............................................445.1 Summary...............................................................................................................445.2 Conclusion............................................................................................................465.3 Recommendation..................................................................................................47 APPENDIX A SIEVE ANALYSIS RESULTS..................................................................................48B MOISTURE CONTENT MEASURED BY NUCLEAR DENSITY PROBE...........58C OVEN MOISTURE CONTENT RESULTS..............................................................62D DATA REDUCING....................................................................................................63D.1 Calculation for Reducing Data............................................................................63D.1.1 Stress..........................................................................................................63D.1.2 Strain..........................................................................................................63D.1.3 Acceleration...............................................................................................64D.1.4 Velocity and Displacement from Acceleration Data.................................64D.1.5 Dynamic Stiffness......................................................................................64D.2 Using Worksheet after 3 Passes with Vi bratory Padfoot Roller in Section 2......65D.2.1 Raw Data...................................................................................................65D.2.2 Reduced Data.............................................................................................66E RESULTS OF SSG.....................................................................................................70F RESULTS OF FWD...................................................................................................72G RESULTS OF ADCP.................................................................................................76LIST OF REFERENCES...................................................................................................82BIOGRAPHICAL SKETCH.............................................................................................83

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vii LIST OF TABLES Table page 4-1. Measured Dry Densities from Nu clear Device within Section 1...............................294-2. Measured and Computed Dry Densities from Nuclear Device within Section 2.......314-3. Measured and Computed Dry Densities from Nuclear Device within Section 3.......324-4. FWD Mean and Standard Deviation on Each Section...............................................364-5. SSG Mean and Standard Deviation on Each Section.................................................384-6. Summary ADCP Results for Section 1.......................................................................414-7. Summary of ADCP Results for Section 2..................................................................414-8. Summary of ADCP Results for Section 3..................................................................415-1. Test Sections and Compactors....................................................................................45A-1. Sample # vs. Location #.............................................................................................48B-1. Data from Nuclear Density Measurement for Section 1............................................59B-2. Data from Nuclear Density Measurement for Section 2............................................60B-3. Data from Nuclear Density Measurement for Section 3............................................61C-1. Data from Oven Moisture Measurement...................................................................62D-1. Factor for Reduci ng of Strain Data............................................................................63D-2. Factor for Reducing of Acceleration Data.................................................................64D-3. Example of Raw Data................................................................................................65D-4. Example of Reduced Data.........................................................................................66E-1. SSG Data for Section 1..............................................................................................70

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viii E-2. SSG Data for Section 2..............................................................................................71E-3. SSG Data for Section 3..............................................................................................71G-1. Slope Summary..........................................................................................................77G-2. DCPI Summary..........................................................................................................78

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ix LIST OF FIGURES Figure page 2-1. Relationships between Density, Co mpaction Energy and Strength vs. Moisture Content. A) Strength vs. Water cont ent for 25% Strain. B) Strength vs. Water content for 5% Strain. C) Dry Density vs. Water Content (Seed & Chan, 1959).......................................................................................................................... .8 2-2. Relationships between Strength Pa rameter (CBR) vs. Moisture Content and Density vs. Various Compaction En ergies (Turnbull & Foster, 1956)......................9 2-3. The LBR vs. Moisture Content Compacted to Dry Density of 123pcf.................10 2-4. Conventional Vibratory Roller.................................................................................11 2-5 Variocontrol Vibratory Rollers..................................................................................12 2-6. One Dimensional Model of Compactor and Subsoil................................................12 3-1. Limerock Grain Size Distribution............................................................................14 3-2. Plan Views of Test Strips at SR-826........................................................................16 3-3. Test Section Compactors..........................................................................................17 3-4. Section 1 Instrumentation Two 6-inch Lifts..........................................................18 3-5. Section 2 Instrumentation 12-inch Thick Lift.......................................................19 3-6. Section 3 Instrumentation 12-inch Thick Lift.......................................................19 4-1. Measured Stress as Function of Ti me Due to a Passing Vibratory Roller...............20 4-2. Stress vs. Number of Passes in two 6-inch lift on Section 1....................................21 4-3. Stresses vs. Number of Passes in the 12-inch Lift of Section 2...............................23 4-4. Stresses vs. Number of Passes in the 12-inch Lift of Section 3...............................24 4-5. Stress vs. Particle Displacemen ts at Bottom of Section 1 during 4th Pass...............25 4-6. Forces on the drum and associated loading loop......................................................25

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x 4-8. Stress vs. Displacement after 7th pass on Section 3.................................................27 4-9. Density Calculations with Depth..............................................................................28 4-10. Strain from LVDT vs. Dry density from NDP for Section 1.................................29 4.11 Strain from LVDT vs. Dry de nsity from NDP for Section 2...................................31 4-12 train from LVDT vs. Dry de nsity from NDP for Section 3.....................................32 4-13. Dry densities and Moistu re Contents in Section 1.................................................33 4-14. Dry Densities and Moistu re Contents in Section 2.................................................34 4-15. Dry Densities and Moistu re Contents in Section 3.................................................35 4-16. Stiffness Measured with FWD in All Sections.......................................................36 4-17. Stiffness measured by SSG in All Sections............................................................38 4-18. Stiffness from FWD & SSG vs. Dynamic Modulus from Vario-System...............39 4-19. Stiffness and Evib Moduli as Function of Depth and Number of Passes................40 4-20 ADCP Data for Section 1 After 2nd Layer...............................................................41 4-21. ACDP Data for Section 2.......................................................................................42 4-22. ACDP Data for Section 3.......................................................................................42 4-23. Comparison ADCP Data from Section 1 and 2......................................................43 4-24. Comparison ADCP Data from Section 1 and 3......................................................43 A-1. Sieve Analysis for S1 and S2...................................................................................49 A-2. Sieve Analysis for S3 and S4...................................................................................50 A-3. Sieve Analysis for S5 and S6...................................................................................51 A-4. Sieve Analysis for S7 and S8...................................................................................52 A-5. Sieve Analysis for S9 and S10.................................................................................53 A-6. Sieve Analysis for S11 and S12...............................................................................54 A-7. Sieve Analysis for S13 and S14...............................................................................55 A-8. Sieve Analysis for S15 and S16...............................................................................56

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xi A-9. Sieve Analysis for S17 and S18...............................................................................57 D-1. Stress from Stress Cell vs.Time...............................................................................67 D-2. Displacement from LVDT vs. Time........................................................................68 D-3. Acceleration vs. Time..............................................................................................69 F-1. D0 Impulse Stiffne ss Modulus for Section 1...........................................................73 F-2. D0 Impulse Stiffne ss Modulus for Section 2...........................................................74 F-3. D0 Impulse Stiffne ss Modulus for Section 3...........................................................75 G-1. Depth vs. Number of Blows for Section 1...............................................................79 G-2. Depth vs. Number of Blows for Section 2...............................................................80 G-3. Depth vs. Number of Blows for Section 3...............................................................81

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xii Abstract of Thesis Presen ted to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Engineering EVALUATING LIMEROCK-BASE THICK LIFT By Jeongsoo Ko August 2005 Chair: Michael C. McVay Major Department: Civil and Coastal Engineering Current Florida Department of Trans portation practice allows maximum lift thickness of 6-inch with no sp ecific controls on moisture. Furthermore, most limerock base courses are compacted with either single or dual steel roller w ith vibratory dynamic forces less than 50,000 lbf. The object of our study was replacement and compaction of a single 12-inch limerock-base lift using a co mpactor with a 63,000 lbf pad-foot roller and an 85,000 lbf heavy smooth roller, instead of two c onventional 6-inch limerock-base lifts. To judge achievement of the replacement, we compared results from one 12-inch and two 6-inch limerock-base lift. The single 12inch limerock-base lift compaction in construction can be achieved under specific c onditions based on sufficient strength and stiffness compared with two conven tional 6-inch limer ock-base lifts.

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1 CHAPTER 1 INTRODUCTION 1.1 General Mechanical compaction of earthen materials has been used for thousands of years. In the US, static/dynamic smooth, pad or sh eep-foot rollers are common in construction of roadway embankments, bases, dams, a nd so on. Generally, field compaction is controlled through dry density and water content establishe d in the laboratory (e.g., Proctor test). In the latter, multiple layers of soil are compacted with constant energies at different moisture content to identify the hi ghest dry density. The higher the dry density and the lower the water content of the de posit, the higher the expected strength and stiffness of the compacted placed backfill. In the field, the contractor has many wa ys to achieve a specific dry density for a specific material and gradation: Different compaction Equipment (vibra tory, static, smooth, pad, etc.) Number of passes Lift thickness Moisture content Stiffness of subgrade soil and base course materials In Florida, most if not all limerock-bas e courses (FDOT Specification 200) have a maximum particle size of 3 and minimum per centage of fines (i.e., passing 200 sieve) of 35%. Current FDOT practice (Specificati on 200) allows maximum lift thickness of 6inch with no specific controls on moisture. Generally, moisture contents vary widely

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2 based on location (5% south Florida to 14% cen tral Florida and north) of mine-material, humidity, and so on. Most, if not all limero ck-base courses are compacted with either single or dual steel rollers with vibrator y dynamic forces less than 50,000 lbf. Of strong interest is the feasibility of co mpacting thicker lifts (e.g., a single 12-inch lift instead of conventional two 6-inch lifts for roadway base courses). The compacting single 12-inch lift appeals to contractors because it reduces costs (especially time). For two conventional 6-inch lifts, the contractor mu st transport the material, grade it, compact it and perform quality control (density, moisture, etc.) twice vs. once with a 12-inch lift. 1.2 Objective Our object was placement and compaction of a single 12-inch limerock-lift instead of two 6-inch lifts over competent subgr ade. We focused on compaction equipment readily available to contractors, and mate rials with no special gradation. Successful placement was judged on similarities of stiffn ess and strength between the thick lift (12inch) and two 6-inch lifts c onstructed using the same mate rial, conditions, and subgrade conditions. To identify the appropriate compaction equi pment, passes, moisture, and so on, we used instrumentation in the base (i.e., st ress cells, LVDTs, and accelerometers). The LVDTs were used to validate densities meas ured with nuclear devices, and the stress cells and accelerometers measured stiffness a nd energies within the compacted fill. Since thick lift limerock compaction has had minimal application in Florida, we decided to select a site, materials, and e quipment with the potential for success. The following were selected: 1) vi bratory pad foot roller or heavy smooth wheel vibratory roller; 2) well graded limerock with limited fines at moisture content on dry of optimum (higher stiffness & strength) and 3) stiff/strong subgrade (LBR > 100).

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3 1.3 Scope The site selected for th ick lift compaction study by the FDOT was SR 826 in Miami Florida, District 4. Located near Mi ami International Airpor t, SR 826 has Oolitic limestone near the surface (i.e., a strong subgrade, LBR>100), with ongoing placement of conventional 6-inch limerock lifts that were we ll graded, low fine content, and moisture content varying from 5 to 9% from the source (i.e., dry of optimum). After discussion with FDOT, Ardaman & Associates and UF personnel, we decided to compact three 100-foot test sections. The first section was to be compacted by conventional means (i.e., two 6-inch lifts using a typical smooth-wheel vibratory compactor). The second 100-foot test section used a 12-inch lift, and the vibratory padfoot roller (55,000 lbf). The th ird 100-foot test section also used a 12-inch lift, but compacted with a heavier smooth-wheel vibratory compactor using intelligent compaction control. The latter roller can meas ure soil stiffness, and can vary the applied vertical dynamic force depending on th e preset stiffness (modulus). For all three sections, we measured verti cal stress, acceleration, and strain for each pass of the roller. We measured nuclear density and moisture content after three or four passes of the compactor on each section. To measure strength and stiffness, we used dynamic cone penetration, falling weight deflec tometer, and the soil stiffness gauge test at ten locations along each section. In addi tion, multiple bag samples were collected both pre and post compaction from each section, a nd sieved to identify particle breakage due to compaction. The following three tasks were completed by FDOT, Ardaman & Associates, and University of Florida to complete the scope of services. 1.3.1 Task 1 The FDOT District CEI performed laborat ory proctor results identifying optimum

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4 moisture content and dry densities. Th e FDOT State Materials Office personnel performed Falling Weight Deflection (F WD) Testing, Automatic Dynamic Cone Penetrometer Testing (ADCPT), Soil Stiffne ss Gage (SSG) testing, bag sampling, and laboratory sieve analysis of pre and post comp acted limerock for the three test sections. 1.3.2 Task 2 Ardaman and Associates placed the instrument ation at multiple depths in each test section, recorded the data for each pass of compactor, and collected nuclear density, and moisture measurements for each test section. 1.3.3 Task 3 University of Florida collected all of the measured data (stresses, strains, accelerations, FWD, ADCP, SSG, etc.) for each section, reduced it (stiffness, moduli, energies, etc.) and compared sections (i.e., 6-inch lift vs. 12-inch).

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5 CHAPTER 2 COMPACTION BACKGROUND 2.1 Field Vibratory Compaction Typical vibratory compaction equipment in cludes hand-held plates (i.e., tampers), and single, and multiple-wheels drum rollers. Our study tested vibrating smooth and padfoot rollers. The basic concept of vibratory roller is to use unbalanced weights to develop sinusoidal forces. In addition all vibratory ro llers (i.e., towed, self-propelled, and/or tandem) have the static weight (motor, fram e, etc.) separated from the vibratory mass through shock absorbers. The total force impart ed to the ground is given in Eq. 2-1. The first term is inertia (dynamic) force due to th e static weight of the drum. The second term is the varying dynamic force due to the rota ting masses within the drum, and the third term is the static weight of both the drum and the rotating masses. Note that the second term is a function of the freque ncy, f, of the rotating masses. .. 2cos()()d Bduufd F mxmrtmmg (2-1) where md = mass of the drum (kg) xd = vertical displacement of drum (m) .. d x = acceleration of drum (m/s2) mf = mass of the frame (kg) mu = unbalanced mass (kg) ru = radial distance at which mu is attached (m) muru = static moment of th e rotating shaft (kg.m) = 2 f t = time elapsed (sec) g = acceleration due to gravity (m/sec2)

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6 f = frequency of the rotating shaft (Hz) Generally, the contribution from the sec ond term is much less than that from the first and third terms. For instance, Forssblad (1965) studied the effect of the vibratory masses on a vibratory rollers compaction. By ad ding 24% of the total roller weight to the frame, a considerable increase in a soils co mpacted density occurred; however, a similar change in the drums weight did not result in an analogous increas e in soil density. Parsons et al. (1962) focused on acceler ating of the vibratory motion (i.e., .. d x in Eq. 2-1). Besides increasing the dynamic force (Eq. 2-1), Parsons et al. found little effect in typical 6 to 9-inch thick lifts that could not be accomplished with more passes of the roller. Yoo (1978) improved field instrumentati on by using inductance coil strain gages for field compaction studies. Their experiment s also varied compactor weight and layer thickness for gravel-sand mixtures compacted dry (4%) of optimum moisture content. Both 12-inch and 36-inch thick fills were co mpacted under various energies and moisture content. They concluded that the maximum compact layer thickness should be limited to 12-inch (vs. 36-inch) from stiffness and dens ities measurements with depth. Similarly, WES (USACE-WES, 1976) carried out compac tion on lean clay (PI=13) with various water contents using a sheep-foot roller. Based on that study, they recommended a limitation of lift thickness of 7-inch. 2.2 Strength, Moisture and Compactive Effort Even though field compaction is generally controlled by dry density and moisture contents, the stiffness and strength of the placed backfill are the properties of interest. For instance, deflection, rutti ng, and bearing failure of a ba se course control its design

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7 (i.e., AASHTO 2002). Since stiffness and strengt h measurements are difficult to perform on a routine basis in field, they have been equated to a materials density and moisture content. Seed and Chan (1959) were one of the first to study the relationship between material strength, compaction effort and moisture for fine-grained soils. Their experiments were performed with Harvard Compaction setup (62.4 cm3 specimen, 0.5inch compacting rod with variable spring sti ffness). Figure 2-1 shows the change in dry density (bottom), small strain stiffness (middle) and large strain stiffness (top figure) vs. moisture content for different compaction energi es. Evident from the figure, stiffness, and density increase with compaction energy for a moisture content dry of optimum. Note the significant reduction in stiffness for a given compactive effort as the moisture content passes wet of optimum. Turnbull and Foster (1956) studied the infl uence of moisture and compactive effort on granular soils in Figure 2-2. Instea d of performing triaxial compression, they conducted California Bearing Ratio (CBR). Sim ilar results as shown in Figure 2.1 are seen in Figure 2.2. Ping et al (1996) has suggested a correlation of 1.25 between the Florida Limerock Bearing Ratio Test (LBR) and CBR results. The FDOT State Materials Office (SMO) co mpacted the Florida limerock to meet LBR requirements. As part of this research, SMO agreed to compact additional specimens to a constant dry density (123 pc f) at different moisture contents with subsequent LBR testing. Figure 2-3 shows vari ation of LBR value with moisture content for both soaked and un-soaked samples. Evident is the higher stiffness/strength of the unsoaked samples dry of optimum (10.5% from st andard proctor). The latter agrees with

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8 A B C Figure 2-1. Relationships between Dens ity, Compaction Energy and Strength vs. Moisture Content. A) Strength vs. Water content for 25% Strain. B) Strength vs. Water content for 5% Strain. C) Dry Density vs. Water Content (Seed & Chan, 1959)

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9 Figure 2-2. Relationships between Strength Parameter (CBR) vs. Moisture Content and Density vs. Various Compaction En ergies (Turnbull & Foster, 1956)

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10 Seed & Chan, and Turnbull & Foster that compaction dry of optimum for a specific dry density would ensure a higher strength and stiffness. Figure 2-3. The LBR vs. Moisture Conten t Compacted to Dry Density of 123pcf 2.3 Intelligent Compaction To perform thick lift placement, one of the Compactor manufacturers, Bomag, recommended the use of their Intelligent Compaction Control (ICC) devices. Conventional vibratory steel wheel rollers, Figure 2.4 em ploy rotating eccentric masses to develop vertical dynamic forces, Eq. 2.1. Moreover, circular motions of the masses are aligned such that the dynamic forces are always vertical. In addition, conventional vibratory rollers operate at either high fre quency and low amplitude or low frequency and high amplitude to prevent damage to the equipment. Recently, a number of manufacturers have implemented more control or feedback

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11 Figure 2-4. Conventional Vibratory Roller between the instrumentation (accelerometer) on the compactors drum, and the force delivered to the ground. One such unit is Bo mags variocontrol Ro ller, shown in Figure 2.5. Assuming a one-degree of freedom model for the compacted backfill, Figure 2.6, the static stiffness, kB, of the base is computed from BBdBd F kxdx (2-2) where kB = stiffness of soil (F/L) xd = vertical displacement of soil dB = damping coefficient (value of 0.2 assumed) d x = velocity of soil mass (measured at drum) Next using Lundbergs (1939) work, the Youngs Modulus, Evib of the compacted soil is found from the soil stiffness, kb, Eq. 2.3: 3 2 21 212.14ln 2 116vib B vib fdEL k LE mmRg (2-3)

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12 Figure 2-5 Variocontrol Vibratory Rollers Figure 2-6. One Dimensional Mo del of Compactor and Subsoil where L = length of roller R = radius of roller = poissons ratio of the soil The variocontrol unit in the manual m ode will automatically display the Evib measurements of the compacted base material, which may be used as quality assessment. In the automatic mode, the user identifies a target Evib value as potential specification; the unit then alters the orientation of rotating masses, automatically directing more or less

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13 dynamic force into the ground. One of Boma gs variocontrol units, BW 225BV-3 was tested at the SR-826 site.

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14 CHAPTER 3 TEST SITE AND INSTRUMENTATION 3.1 Materials, Site Layout, and Equipment A typical grain size distribution curve for th e compacted Florida limerock at SR-826 is shown in Figure 3-1. AASHTO classification of the material is A-1-a, or GW within the Unified Soil Classification System. Grain Size distributions for all of test sections are given in Appendix A as reported by the Stat e Materials Office. Laboratory modified proctor analysis revealed a maximum dry de nsity of 131 pcf and an optimum moisture content of 9%. FDOT Standards Specification 200 required a final pl aced dry density of 128.4 pcf (i.e., 98%) for successful base construction. 0.10 DIAMETER (mm)% FINER 0 10 20 30 40 50 60 70 80 90 100 0.01 1.00 10.0 100.0 S-3 S-4 Figure 3-1. Limerock Grain Size Distribution Figure 3-2 shows the plan view for all thr ee-test sections at SR-826. All Sections were placed over preexisting lime rock with LBR values above 100.

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15 Section 1, located from stations 227 to 228, at the northeastern quadrant of the site had two conventional 6-inch lifts placed over existing subgrade. The section was compacted with a Bomag BW 211D-3, a smooth wheel vibratory compactor with a maximum vertical dynamic force of 53,000 lbf, Figure 3-3 Sections 2 and 3 on the easte rn portion of the site, i nvolved placing loose limerock with dump trunks, and spreading with a dozer to a depth of approximately 13-inch (i.e., compacted 12-inch) prior to compaction. S ection 2 was compacted with a Bomag BW 213PD-3 pad foot roller with maximum dynamic force of 62,000 lbf and a pad height of approximately 4 inches. This device was selected to ensure higher stresses, energies, etc. deeper within the limerock (i.e., densification of the bottom 1/3 of the lift). Section 3 was compacted with a new Bomag variocontrol unit, BW 225 BV-3. The unit is the largest smooth wheel vibratory roller that Bomag manufactures, capable of developing 85,000 lbf of dynamic force. As id entified in Chapter 2, the unit either measures the Modulus, Evib, of the layer (manual mode) or will adjust the dynamic force imparted to the base to obtain a preset Evib values with travel. The unit was run in both modes for this effort. Figure 3-2 shows the 10 locations of th e of the Falling Weight Deflectometer (FWD), Soil Stiffness Gage (SSG), and Automatic Dynamic Cone Penetrometer Tests (ADCPT) which were preformed at the finish of compaction for each test section by the State Materials Office Personnel. Figure 3-1 also shows the location of buried instrumentation, discusse d in the next section. 3.2 Embedded Instrumentation To evaluate the compaction process with de pth, instrumentation was placed at 1/3 points within the base layer. Since one of th e compaction units was a pad foot roller with

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16 Figure 3-2. Plan Views of Test Strips at SR-826 the potential of damaging the instrumentation, it was decided to locate all the equipment at the bottom of each 1/3 locations.

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17 Figure 3-3. Test Section Compactors Of interest are the stresses, energies, sti ffness, and strains with depth as compared to the observed laboratory respons e (i.e., proctor, LBR, etc.). For instance, it is expected that dry densities found in the laboratory w ould be achievable in the field if similar energies (compaction) were applied. In addi tion, comparisons of density at the bottom of the thick lift computed from nuclear density device vs. measured stra ins are of interest (i.e., verification). To accomplish the latter the following instrumentation was installed: 3.2.1 Accelerometers Of interest are displacements as a function of dynamic vibrations due to the roller. Initial attempts used velocity sensors like those employed in seismic geophones. Unfortunately, the latter gene rally do not provide the n ecessary response times. Subsequently, it was decided to employ accel erometers and integrate the response to

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18 obtain displacements. To provide accurate, re peatable information, DC accelerometers of the capacitive resistan ce type were employed (i.e., capable of 0Hz or 1g response). The devices were attached or placed in the vicinity of the stress cells. 3.2.2 LVDT Initially, it was planned to read the LVDTs only after a pass of compactor. However, from the analog nature of th e device and with a sufficiently sampling frequency with the data acquisition system, th e relative displacements or strains may be obtained during the compaction process. To ma intain the location of the devices, as well as their orientation, the LVDTs had 3-inch plas tic plates attached to the top of the LVDT housing as well end of sensing rod. 3.2.3 Stress Cell To measure the vertical stress as a function of compactor motion, 12-inch diameter stress cells were employed. The sensing face was filled with incompressible fluid and the pore transducer was attached 18-inch from the sensor with steel lines. Ardaman and Associates calibrated the devices in the laboratory for Florida limerock. Figure 3-4. Section 1 Instrume ntation Two 6-inch Lifts

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19 Figure 3-5. Section 2 Instrume ntation 12-inch Thick Lift Figure 3-6. Section 3 Instrume ntation 12-inch Thick Lift

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20 CHAPTER 4 RESULTS AND DISCUSSION 4.1 Stress Measurements Typical recorded vertical stresses as a function of time due to a passing vibratory roller is shown in Figure 4-1. Each peak represents a rotation of the vibratory mass, which is happening at approximately 30 Hz (i. e., 6 peaks or rotations/0.2sec). Evident is the buildup of stresses as the roller approaches th e instrumentation, with the maximum occurring with roller over the gage. Of intere st are the stress changes vs. particle motions (e.g., stiffness and energies), as well the peak stresses at various depths within the base layer. Presented in this section are the peak (maximum) stresses as function of depth vs. the number of passes. Figure 4-1. Measured Stress as Function of Time Due to a Passing Vibratory Roller Figure 4-2 shows the peak stresses for S ection 1 vs. pass # of the BW 211D-3. The left side of the figure depicts the stresses at the middle and bottom (Figure 3-4) of the

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21 first 6-inch lift for three passes. The right side of the figure show the stresses at the middle and bottom of the first lif t, as well as stresses at th e bottom of the second 6-inch lift for an additional 4 passes of the BW 211D -3 compactor. Evident from the figure is the large difference in stresses between the middle and bottom (i.e., 3-inch vs. 6-inch) of the 1st layer. However, with the placement of the second lift, there is little difference in stresses from 6-inch to 12-inch as seen fr om the right side of Figure 4-2. The larger difference in stresses at top vs. bottom was attributed to Boussinesqs equation and the influence of the square of the depth below compactor on stress. Figure 4-2. Stress vs. Number of Passe s in two 6-inch lift on Section 1 Figure 4-3 shows the maximum stresses at depths of 4.98, 9.12, and 13.5 inches in the base for each pass of the BW 213PD-3 padfoot roller (passes 1-3, and 5-6), and BW 211D-3 smooth wheel roller (pass 4, and 7-8) in Section 2. Note, that a pass (i.e., from 6

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22 to 7) has two points (i.e., 6.5 and 7) whic h represent the compactor traveling from the south to the north side of the site (i.e., 6.5) and subsequently back from the north to south side (i.e., 7) of Section 2. Note passes, 4, 7, and 8 with the smooth wheel vibratory roller were performed to ensure a smooth surface required in nuclear backscatter moisture monitoring. Figure 4-3 shows the stresses measured at all three instrumented depths were quite similar for the pad foot versus the smooth wheel roller. The latter is attributed to the larger contact area provided by the pads as well as their deeper penetration (i.e., 4-inch high pads) vs. the smooth wheel roller. Also, note the similarity in stress (150 psi) reported in Section 2 vs. Section 1 for 1st set of gages for the smooth wheel roller. Figure 4-4 shows the maximum vertical s tresses with depth (6.1, 9.4, and 13 inches) as a function of pass for the heaviest of the smooth wheel rollers (i.e., BW 225BV-3 (85,000 lbf). Apparent from a compa rison of Figures 4-2 and 4-4, the stresses between Sections 1 and 3, are approximately 1.6 times higher in Section 3 versus Section 1 due to increased dynamic force of the BW 225BV-3 (85,000 lbf) vs. BW 211D-3 (53,000 lbf ). Also note however, the stresses vari ations observed in Section 2 for the smaller smooth wheel roller (i.e., passes 7, 8) in Figure 4-3, do not occur in Section 3 for the heavier smooth wheel roller. The latter may be due to particle crushing and larger contact area under the compactor for the heavier roller (BW 2 25BV-3). Of interest are the particle motions, which are occurring with the stress changes. 4.2 Compactive Energy vs. Depth To identify soil particle dynamic movement and subsequent energy transmissions, accelerations were monitored with DC (0-100 Hz) piezo-capacitance instruments attached to the tops of the stress cells at the three depth locations (Fi gure 3-4, 3-5, & 3-6).

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23 Figure 4-3. Stresses vs. Number of Pa sses in the 12-inch Lift of Section 2 After integrating the accelerations twice, the particle displacements during a pass of a compactor were obtained. Appendix D presents the data reduction process, as well as an example of deformations as a function of time. Of interest is the relationship between stress and deformation as a function of comp actor motion. Figure 4-5 shows the typical stress vs. particle motion at the bottom of Section 1 during the 4th pass of the BW 211D-3. Each loop (ellipse) represents one complete rotation of the eccentric mass within the roller (i.e., 30 Hz or 30 cycles/sec in Figure 4-1). The multiple loops with varying peak stresses are a result of the roller either approaching or moving away from the instrumentation. Note the similarities of Figure 4-5 and Bomags force vs. displacement measurement of the drum at the ground su rface, Figure 4-6. As identified by Bomag, Figure 4-6 shows the compression is a result of the compactor pressing down on the base,

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24 Figure 4-4. Stresses vs. Number of Pa sses in the 12-inch Lift of Section 3 and the expansion (i.e., unloading) is due to the drum unloading the base. In the unloading phase, the particle displacements ar e negative (i.e., in an upward direction. The energy transmitted to the base for each rotation of eccentric mass within the roller is the area within each loop, Figure 4-6. Figure 4-7 shows the stresses vs. displacements at the top, middle and bottom of Section 2 in the 5th pass of the BW 213PD-3 pad foot roller. Apparent is the similarities of energies (i.e., areas) at the various depths within the 12-inch lift, with a slight drop at the bottom. Interestingly, the slopes (i.e., st iffness) of the middle and bottom depths of the lift are higher than the top. The latte r may be attributed to the shape of the compactors contact area (i.e., pad, vs. the smooth wheel). Figure 4-8 shows the stresses vs. displacements at the top, middle and bottom of Section 3 in the 7th pass of the BW 225BV-3 smooth wheel roller. Evident is the

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25 Figure 4-5. Stress vs. Parti cle Displacements at Bottom of Section 1 during 4th Pass Figure 4-6. Forces on the drum and associated loading loop similarities of energies (i.e ., areas) at the top and bottom of 12-inch lift, suggesting similar densities throughout the deposit. A comparison of energies (areas) between Section 1 (Figure 4-5) and 3 (Figure 4-7), s uggest higher densities changes or compaction is being performed with one pass of the BW 225BV-3 vs. 211D-3. Also note that the

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26 Figure 4-7. Stress vs. Displacement after 5th Pass on Section 2 stiffness (i.e., slopes) of any loop is highe r for the BW 225BV-3 (F igure 4-8), than the slopes from Section 1 (Figure 4-5) with the pa ssing of a Bomag 211. Th e latter should be evident from Falling Weight Deflectometer (FWD) data discussed later. 4.3 LVDT Strains & Measured Densities Of interest were the strains, which may be e quated to density as function of depth within the base course. FDOTs current nuclear dens ity devices place the probe at depths of 6 and 12 inches, Figure 4-9. Due to the location of the source (various depths) and receiver (surface), the density at 0 to 6-inch (1) is accurate, as well the average 0 to 12-inch (t), however, the density from 6 to 12-inch (2) is generally computed from the following simple averaging assumption: 112212()tdddd (4-1)

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27 or solving for 2, 1211 2 2()()tddd d (4-2) Figure 4-8. Stress vs. Displacemen t after 7th pass on Section 3 Knowing the moisture content, the average or indivi dual dry densities ( d1 d2) may be found as: 1d (4-3) For the device shown in Figure 4-9, the moisture content, is computed near the surface (i.e., back scatter). For all calculations to follow, it is assumed that the moisture content with depth is constant (i.e., = 1 = 2). Given the uncertainty of the density calculations, it was of interest to check their

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28 Figure 4-9. Density Calculations with Depth values with other methods (e.g., strain meas urements from LVDT). Knowing the original spacing between a pair of LVDT plates (i.e., Fi gures. 3-4 ~ 3-6), the strain as a function of compactor pass may be found as, vchangeinspacing Loriginalspacing (4-4) Next, assuming that the initial dry density ( d_initial) of the placed base material is uniform, the final dry density ( d_final) after a pass may be computed as, _1dinitial dfinal v (4-5) Where v is given by Equation 4-4, and it is assumed that no horizontal strains develop as the compactor passes over. Figure 4-10 shows a comparison of the stra ins vs. number of passes in the top 6inch lift of Section 1. Evident the strains increased by 6% in first pass and then to 9% by the 4th pass. Using the strains, initial dry density and Eq. 4-5, the computed dry density vs. pass is shown on the left axis. The computed dry density from the nuclear moisture and density device is given in Table 4-1, as well as depicted in Figure 4-10. Note the moisture

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29 and densities were measured at 3 locations wi thin the section, and LVDT occurred at one location. As expected, the measured density variability of the first pass, 3.5 pcf (126.6 pcf.1 pcf), is quite high and if added to the mean (124.8 pcf), covers the density measured by the LVDT (127 pcf), which is at one point. Figure 4-10. Strain from LVDT vs. Dry density from NDP for Section 1 Table 4-1. Measured Dry Densities fr om Nuclear Device within Section 1 Pass # Depth 1 2 3 AverageStandard Deviation 0 0~6 120.50 115.20118.90118.20 2.72 1 0~6 123.10 126.60124.80124.83 1.75 3 0~6 128.80 128.40N/A 128.60 0.28 4 0~6 129.60 130.20130.10129.97 0.32 Figure 4-11 shows the strains in the bottom third and middle third (Figure 3-6) of Section 2 as a function of passes. Evident from the Figure, the strains within the bottom and middle third of the thick (12-inch) lift are quite similar from the pad-foot compactor, suggesting uniform compaction. Table 4-2 shows nuclear density measuremen ts at 3 locations within Section 2 for

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30 passes 0, 4, and 9. Note, in order to measur e density, the surface of the section had to be graded and rolled with the vibratory smooth steel compactor (4th and 6th passes). The table presents the measured values at 6 inches (i.e., 0~6-inch), 12 inches (i.e., 0~12-inch), as well as the computed value from 6~12-inch based on Eq. 4-2. As expected, the highest standard deviation occurred within the 6~12-inch zone; however, the variability decreased with pass, which is good. A co mparison between densities measured or computed from the Troxler nuclear device or strain LVDT sensors were quite favorable. Figure 4.12 shows the measured strains in th e bottom and middle third (Figure 3-7) of Section 3 as a function of compactor pass. Figure 4.12 shows the strains in Section 3 are highest for all sections (max. 20%) due to the dynamic force o f compactor, 85,000 lbf. Also evident, the strains within the bottom and middle third of the thick (12-inch) lift are very similar, suggesting uniform compaction. Given in Table 4-3 are nuclear density m easurements at 3 locations within the section for passes 0, and 9. No other densitie s were collected due to time constraints (end of day, darkness). Evident from the table, the densities of Sect ion 3 at the end of compaction were the highest and they agreed with the back computed values from the LVDT instrumentation, Figure 4-12. 4.4 Measured Dry Densities and Moistures vs. FDOT Specified Values As identified in section 3.1, Modifi ed Proctor (AASHTO T-180) laboratory compaction tests were performed on the SR826 base materials. An optimum dry density of 131 pcf and moisture content of 9% wa s found. FDOT specification 200 requires a measured field compaction of 98% of T-180 or a dry density of 128.38 pcf. Figure 4-13 shows measured field dry densities from th e nuclear density probe (NDP) for the last passes of lifts 1 and 2 of Section 1. Figur e 4-13 also shows the moisture contents

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31 measured from the NDP (nuclear density prob e) as well as oven samples recovered from the field. Apparently the back scatter surface moisture measurement is acceptable measurements over the depth of the deposit. Figure 4.11 Strain from LVDT vs. Dr y density from NDP for Section 2 Table 4-2. Measured and Computed Dry Dens ities from Nuclear Device within Section 2 Pass # Depth 1 2 3 Average Standard Deviation 0~6 117 116 116 116.33 0.58 0~12 116.1 117.3 114.4 115.93 1.46 0 6~12 115.2 118.6 112.8 115.53 2.91 0~6 126.9 128.3 122.6 125.93 2.97 0~12 126.8 129.8 125 127.20 2.42 4 6~12 126.7 131.3 127.4 128.47 2.48 0~6 134.3 135 133.8 134.37 0.60 0~12 134.5 133.2 132.3 133.33 1.11 9 6~12 134.7 131.4 130.8 132.3 2.1 Figure 4-13 shows the dry density measuremen ts in the first lift (129 pcf) increased significantly during the compaction of the overlying second lift (133.5 pcf). The latter may be attributed to the large compactor ener gy (Figure 4-5) measured in the bottom of

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32 Figure 4-12 train from LVDT vs. Dr y density from NDP for Section 3 Table 4-3. Measured and Computed Dry Dens ities from Nuclear Device within Section 3 Pass # 0.47 1.19 0 2.38 0~6 135.5 139.3 137.40 1.90 0~12 141 137 139.00 2.00 9 6~12 146.5 134.7 140.60 -first lift during compaction of 2nd lift. Both lifts are well above FDOT Specification 200 or 98% of the modified Proctor or a dry density of 128.38 pcf. Figure 4-14 shows easured dry densitie s and moisture contents for the 9th compactor pass on Section 2. Evident are sim ilarities of densities for both 0~6-inch and 0~12-inch zones for all 10 locations within Section 2. Also note the similarities of moisture obtained from both the oven samples and NDP (nuclear density probe).

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33 Evident is that the measured densities are well above the required FDOT specification value of 128.38 pcf. Figure 4-13. Dry densities and Moisture Contents in Section 1 Figure 4-15 shows measured dry densities and moistures in Section 3 for the 9th pass of the BW 225BV-3 compactor. This sectio n had the highest measured densities, as well as variability along the s ection. However, the densi ties were well above FDOTs Specification 200 of 128.3 pcf. 4.5 Base Stiffness As identified in section 2.2, the stiffness, and strength of compacted materials are a function of moisture content and compactive effort (energy). Since, future roadway base construction will be based on compacted sti ffness, AASHTO (2002), the stiffness of two conventional 6-inch lifts versus the 12-inch thick lift are of great interest For the stiffness

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34 measurements, Falling Weight Deflectometer (FWD), Soil Stiffness Gage (SSG), as well as the Evib from the Bomag Varicontrol measurem ents on the drum (BW 225BV-3) were measured and compared. FWD and SSG were measured after compaction while Evib from the Bomag variocontrol was measured during compaction. Figure 4-16 shows stiffness (Kips/in) m easured from the FWD for both lifts of Section 1, as well as the thick lift Sections 2 and 3 at 10 separate locations. Table 4-4 shows the mean and standard deviation for all ten locations in each section. Figure 4-14. Dry Densities and Moisture Contents in Section 2 As expected, the stiffness of the first lif t of Section 1 increased with the placement of the second lift due to the compactive effort (energies) improving the underlying layer (Figure 4-5) densities as shown in Figure 4-13. Interestingly, the FWD stiffness of Section 2 had the highest mean fo r all the tested sites as well as the lowest coefficient of

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35 variation (i.e., standard deviation divided by mean). However, Section 3, which had the highest compactive effort, and used the va riocontrol Compactor, had the lowest FWD mean stiffness, as well as the worse variabi lity. Note however, the FWD employs a larger loading surface (i.e., 18-inch diameter plate), which has a deeper zone of influence than the variocontrol compactor drum. Figure 4-15. Dry Densities and Moisture Contents in Section 3 Figure 4-17 shows the surface stiffness as measured by the soil stiffness Gage (SSG) from Humbolt device for each of the ten locations within the 3 Sections. Again, Section 1 had SSG performed at the end of bot h the first and second 6-inch lift placement. Table 4-5 shows mean and standard deviation of the SSG data. Interestingly, the mean stiffness for the first 6-inch was higher than the measured mean af ter compaction of the second 6-inch lift for Section 1. This quite different than the FWD results, Table 4-4,

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36 Figure 4-16. Stiffness Measured with FWD in All Sections Table 4-4. FWD Mean and Standa rd Deviation on Each Section Section1 Average Standard Deviation 0~6inch 297 28.32 6~12inch 311 29.78 0~12inch 304 29.15 Section2 -------0~12inch 362 34.05 Section3 ------0~12inch 303 81.76 suggesting the SSG is measuring a surface phenomenon, whereas, FWD is measuring a depth phenomenon. Again Section 2, 12-inch lif t with the pad foot compactor, had the highest stiffness, whereas Secti on 3 was in between section 1 (2nd lift) and Section 2 on average, but had the worst variab ility (standard deviation 3.98). Also of interest is a comparison of stiffness and moduli, Evib, as measured with the FWD, SSG, and the variocontrol unit for Section 3. It is envisioned that Intelligent

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37 compaction Devices (i.e., varicontrol, etc.), which continuously monitor stiffness or moduli, will replace nuclear density for quality assessment and control in compaction. Figure 4-18 shows FWD and SSG stiffness (das hed lines read on left axis), versus the Evib measurements (read on the right side) as reported by the variocontrol unit as a function of location. Note the varicontrol Unit was operated in automatic (A, i.e., preset Evib), and manual (R, i.e., preset amplitude and frequency) modes. Interestingly, after the first pass, all subsequent passes of the variocontrol unit, had smaller Evib. Moreover, the variability of the Evib values over the site (i.e., 1-10) is much greater than the initial values (i.e., pass 1) or FWD data. All of the latter suggest that the unit was possibly crushing the surface material in site 3. For instance, particle crushing would result in larger surface deformations or a lower stiffness, k (Eq. 2-2), and a lower Evib (Eq. 2-3) with subsequent pass. To further verify the particle crushing theory, the stiffness as a function of depth was found from the stress gages and accelerometers located 6-inch, 9-inch and 13-inch below the surface, Figure 3-6. The stiffness was asse ssed for the loading phase (e.g., Figure 4-8) and was compared to the Evib, in Figure 4-19. Figure 4-19 shows the stiffness 6-inch or below increased or remained constant for all passes as compared the surface Evib measurements (x axisdecreased). The sensor 6-inch below the surface reached its maximum on the 4th pass, whereas, the bottom (13-inch) reached maximum at the 6th pass. The increasing stiffness values below 6-inch, supported by the higher densities in Figure 4-15, are in confli ct with the decreasing Evib values with pass number. Further confirmation of the influence of compactive effort (energies), Figure 4-8, are presented in section 4.6, concerning strength vs. depth.

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38 Figure 4-17. Stiffness measured by SSG in All Sections Table 4-5. SSG Mean and Standa rd Deviation on Each Section Section1 Average Standard Deviation 0~6inch 14 2.33 6~12inch 12 1.64 0~12inch 13 2.14 Section2 ----0~12inch 15 3.50 Section3 ----0~12inch 13 3.98 4.6 Base Strength vs. Depth Besides stiffness, the strength of base materials beneath the roadway is extremely important. The latter controls maximum contact pressures (e.g., semi-truck tire pressures) that the roadway may be expos ed without undergoing a bearing failure. One means of assessing strength in the field is w ith a static or dynamic cone penetration test.

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39 For this study, an Automatic Dynamic Cone Penetrometer (ADCP) device owned and operated by the State Materials Office (SMO) in Gainesville was used. SMO recommended the automatic dynamic cone over the static due to its prior success on other base project studies. Figure 4-18. Stiffness from FWD & SSG vs. Dynamic Modulus from Vario-System Figure 4-20 shows the mean and maximum range of ADCP values as a function of depth for Section 1 after the pl acement of the second 6-inch lift. Appendix G presents the data for all ten locations (Figure 3-5), a nd Table 4-6 reports the mean and standard deviation of the ten values at depths of 6-inch, 10-inch and 12-inch below the base surface. Of interest is the number of bl ows required to achieve a specific depth, discontinuities (i.e., jumps due to impenetrab le rocks schist), as well as the slope (blows/distance) over a given layer. Figur e 4-20 shows Section 1 after compaction was

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40 very uniform with blow count/layer (strength) being similar for each 6-inch lift as well as the subgrade (zone below the base). Figure 4-19. Stiffness and Evib Moduli as Function of De pth and Number of Passes Figure 4-21 and Table 4-7 shows the mean, range, and variability of ADCP data for Section 2. Table 4-8 and Figure 4-22 show s the mean, range and variability of ADCP data for Section 3. A comparison of mean ADCP data between Section 1 and 2 is given in Figure 4-23. Evident the mean for both sections are quite similar. However, the mean ADCP data for Section 3 is significantly higher th an Section 1, by a factor of 2. The latter suggests that the significant energies (Figure 4-8) from BW 225BV-3 resulted in particle crushing of the surface (Figure 4-18), but higher strength (Figure 4-22) and stiffness (Figure 4-19) in the underlying materials due to larger contact area and dynamic drum forces in Section 3.

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41 Figure 4-20 ADCP Data for Section 1 After 2nd Layer Table 4-6. Summary ADCP Results for Section 1 Depth Average Blow Standard Deviation 6 24 5.34 10 51 8.1 12 64 7.71 Table 4-7. Summary of ADCP Results for Section 2 Depth Average Blow Standard Deviation 6 29 6.69 10 50 9.27 12 59 10.49 Table 4-8. Summary of ADCP Results for Section 3 Depth Average Blow Standard Deviation 6 49 12.27 10 80 12 12 94 9.5

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42 Figure 4-21. ACDP Data for Section 2 Figure 4-22. ACDP Data for Section 3

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43 Figure 4-23. Comparison ADCP Data from Section 1 and 2 Figure 4-24. Comparison ADCP Data from Section 1 and 3

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44 CHAPTER 5 SUMMARY, CONCLUSION AND CONCLUSIION 5.1 Summary Current practice in Florida for the construction of 12-inch limerock bases for roadways is to compact two 6-inch layers on top of one another. The latter is generally accomplished with single or dual drum vibrator y steel wheel rollers with dynamic forces in the 30,000 to 50,000 lbf range. In addi tion, FDOT Construction Specification 200 stipulates that limerock must be compact ed to 98% of the maximum dry density as obtained in a laboratory Modified Proctor (AASHTO T-180) test. To accelerate roadway construction, and re duce costs, contractors and compactor manufacturers have suggested placement of a single 12-inch base lift instead of two 6inch layers. For instance the time required for quality control testing, grading, trucking, scheduling, and delivering a single 12-inch la yer instead of two 6-inch lifts might be substantially reduced. In addi tion, compactor manufacturers have developed intelligent and heavier compactors that are capable of va rying the energy delivered to the base, as well as monitoring the stiffness of the compacted material. To investigate the possibility of compacting 12-inch thick lifts, three tests were conducted. Table 5-1 describes the condition of each test section. One test section had two conventional 6-inch lifts, and other two test sections were 12-inch thick lifts employing different compaction equipment (i.e., pad foot vs. smooth wheel, Table 5-1). The Miami site was selected due to its subgrade stiffness (i.e., LBR>100), as well as properties of its placed limerock: well gr aded, and low fine content with moisture

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45 contents from the mine less than optimum (i. e., 4% ~7% as dry part of 9% as optimum water content). As identified in the literature and lab (Chapter 2), compacting dry of optimum results in greater stiffness and strength. Table 5-1. Test Sections and Compactors Location Compactor Dynamic Force (lbf) Compactor Detail Applied Lift Thickness Section 1 BOMAG BW 211D-3 53,000 Vibratory Steel Smooth Roller used conventionally Conventional lifts (e.g., two 6-inch) Section 2 BOMAG BW 213PD-3 62,000 Vibratory Padfoot Roller 12-inch thick lift Section 3 BOMAG BW 225BV-3 85,000 Vibratory Smooth WheelICC Unit 12-inch thick lift To identify stresses, deformations, and energies within the 6-inch and 12-inch lifts, stress gages, accelerometers, and LVDT defo rmation sensors were placed in the top, middle and bottom third of each placed laye r. After compaction of each lift, Falling Weight Deflectometer (FWD), Soil Stiffness Gage (SSG), and Automatic Dynamic Cone Penetrometer (ADCP) testing were performed at 10 locations within ea ch site with 1foot interval. Of interest were the densities, stiffness, and strengths of material as a function of depth for the two 6-inch vs. 12-inch thic k lifts. Also of importance was the Moduli, Evib, from Bomags Intelligent Compaction Control (ICC) unit vs. field measured stiffness. As expected, the two 6-inch lif ts, Section 1, reached 98% of maximum dry densities within 3 to 5 passes of the c onventional smooth steel vibratory compactor. Strains within the lifts were 6 to 9% with appreciable increase in density occurring within the lower lift as the uppe r lift was compacted. Compaction of Section 2, a 12-inch thick lift occurred with alternating passes of BW

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46 213PD-3 (5 passes) (i.e., a vibratory a pad f oot roller), and a BW 211D-3 (i.e.,vibratory smooth wheel roller) to smooth the base surface in order obtain accurate moisture and density measurements. From the field instrumentation, the strains and back computed densities (Troxler Nuclear Device) in the bottom and the middle of the Section 2 were quite similar. In addition, the energies a nd stiffness throughout the depth compared quite favorably. Surface stiffness measured with eith er FWD or SSG were similar or slightly higher with the thick lift, 12 -inch section vs. the conven tional Section 1. Strength measured by ADCP and its associated coeffici ent of variability were quite similar for both Section 1 and Section 2. Section 3 was a 12-inch thick lift base compacted with the smooth wheel BW 225BV-3 varioconrol compactor, which can co ntinuously monitor surface stiffness and varies energies based on moduli, Evib. The compactor had the greatest dynamic force, 85,000 lbf, of any of the tested units. The meas ured strains with depth were quite uniform with depth and the highest of all the test se ctions, 20%. Similarly, the strength measured with depth by the ADCP was also the highest of all the test sections (i.e., factor of 2). Unfortunately, even though the variocontrol unit was run in both the automatic and the manual mode, the surface stiffness or moduli, Evib, decreased with pass number and was quite variable over the section. The variability attributed to particle crushing of the surface particles, since the measured stiffness, and strength, increased in depth with pass based on buried instrumentation and ADCP results. 5.2 Conclusion From the study, it was conclude that thick lift, 12-inch, compaction of limestone base courses was achievable under the following conditions: Subgrade material of sufficient strength and stiffness (i.e., LBR value over 100).

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47 The compaction process should be conducted with moisture contents on dry part of optimum (i.e., 5~8% vs. 9% optimum moisture content). Vibratory padfoot roller w ith at least 60,000 lbf of dynamic force or vibratory heavy steel smooth roller above 85,000 lbf dynamic force. 5.3 Recommendation With the successful compaction of thick lift limestone base course in south Florida, the question of its use in central and north Florida remains. Miami was selected due to its potential for success (i.e., well graded limerock, low fine content, and moisture content dry of optimum, as well as stiff subgrade, LBR greater than 100). The next potential test scenario should be: Subgrade stiffness (LBR>100) (i.e., lift placed on stiff limerock subgrade) Vibratory pad-foot roller with at leas t 60,000 lbf of dynamic force or vibratory heavy steel smooth roller above 85,000 lbf dynamic force Limerock material with higher fine content and moisture content wet of optimum, as typically found in Central Florida. Also, the stiffness (FWD and SSG) and s trengths (ADCP) devices should be the minimum instrumentation used in the future study.

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APPENDIX A SIEVE ANALYSIS RESULTS Table A-1. Sample # vs. Location # Sample # Location# S-1 1 S-2 1 S-3 7 S-4 7 S-5 9 Section 1 S-6 9 Sample # Station S-7 2 S-8 2 S-9 5 S-10 5 S-11 9 Section 2 S-12 9 Sample # Station S-13 3 S-14 3 S-15 6 S-16 6 S-17 8 Section 3 S-18 8

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49 Figure A-1. Sieve Analysis for S1 and S2 0 10 20 30 40 50 60 70 80 90 100 0.01 0.10 1.00 10.00 100.00 DIAMETER (mm)% FINER S-1 S-2

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50 Figure A-2. Sieve Analysis for S3 and S4 0 10 20 30 40 50 60 70 80 90 100 0.01 0.10 1.00 10.00 100.00 DIAMETER (mm)% FINER S-3 S-4

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51 Figure A-3. Sieve Analysis for S5 and S6 0 10 20 30 40 50 60 70 80 90 100 0.01 0.10 1.00 10.00 100.00 DIAMETER (mm)% FINER S-5 S-6

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52 Figure A-4. Sieve Analysis for S7 and S8 0 10 20 30 40 50 60 70 80 90 100 0.01 0.10 1.00 10.00 100.00 DIAMETER (mm)% FINER S-7 S-8

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53 Figure A-5. Sieve Analysis for S9 and S10 0 10 20 30 40 50 60 70 80 90 100 0.01 0.10 1.00 10.00 100.00 DIAMETER (mm)% FINER S-9 S-10

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54 Figure A-6. Sieve Analysis for S11 and S12 0 10 20 30 40 50 60 70 80 90 100 0.01 0.10 1.00 10.00 100.00 DIAMETER (mm)% FINER S-11 S-12

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55 Figure A-7. Sieve Analysis for S13 and S14 0 10 20 30 40 50 60 70 80 90 100 0.01 0.10 1.00 10.00 100.00 DIAMETER (mm)% FINER S-13 S-14

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56 Figure A-8. Sieve Analysis for S15 and S16 0 10 20 30 40 50 60 70 80 90 100 0.01 0.10 1.00 10.00 100.00 DIAMETER (mm)% FINER S-15 S-16

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57 Figure A-9. Sieve Analysis for S17 and S18 0 10 20 30 40 50 60 70 80 90 100 0.0 0.1 1.0 10.0 100.0 DIAMETER (mm)% FINER S-17 S-18

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APPENDIX B MOISTURE CONTENT MEASURED BY NUCLEAR DENSITY PROBE

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59Table B-1. Data from Nuclear De nsity Measurement for Section 1

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60 Table B-2. Data from Nuclear De nsity Measurement for Section 2

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61 Table B-3. Data from Nuclear De nsity Measurement for Section 3

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APPENDIX C OVEN MOISTURE CONTENT RESULTS Table C-1. Data from Oven Moisture Measurement SR 826 Oven Moistures Test Date 11/30/2004 Sample # Section1 Location % M 1 0" to 6" 1 6.98 2 6" to 12" 1 6.39 3 0" to 6" 7 5.53 4 6" to 12" 7 5.5 5 0" to 6" 9 5.28 6 6" to 12" 9 5.55 Test Date 12/1/2004 Sample # Section 2 Location % M 7 0" to 6" 2 6.88 8 6" to 12" 2 6.79 9 0" to 6" 5 6.7 10 6" to 12" 5 7.5 11 0" to 6" 9 6.62 12 6" to 12" 9 7.78 Test Date 12/1/2004 Sample # Section 3 Location % M 13 0" to 6" 3 7.34 14 6" to 12" 3 6.84 15 0" to 6" 6 7.22 16 6" to 12" 6 7.77 17 0" to 6" 8 6.08 18 6" to 12" 8 6.1

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APPENDIX D DATA REDUCING D.1 Calculation for Reducing Data D.1.1 Stress Reducing Data = (Raw Data-Initial Value)*100 (Initial Value is the average value of valu es measured during last 0.4 sec in whole measuring time, 10 sec) D.1.2 Strain Reducing Data= (Raw Data-Initial Value)*Factor (Initial Value is measured before test) Table D-1. Factor for Reducing of Strain Data Section 1 Section 2 Section 3 CH 6 (Bottom 1/ 3) 0.4072 0.3966 0.4054 CH 7 (Middle 1/3) 0.4058 0.4054 0.3990 The above factors are calibrated by ARDAMAN & Associates. 63

PAGE 76

64 D.1.3 Acceleration Reducing Data= (Raw Data-Initial Value)*Factor*32.17417*12 (Initial Value is the average value of valu es measured during last 0.4 sec in whole measuring time, 10 sec) Table D-2. Factor for Reducing of Acceleration Data Section 1 Section 2 Section 3 CH 1 (Bottom) 2.5497 2.5484 2.5259 CH 3 (Middle) 2.5484 2.5368 2.5510 CH 5 (Top) 2.5478 2.5336 2.5272 The above factors are calibra ted by ARDAMAN & Associates. D.1.4 Velocity and Displacement from Acceleration Data 111 111()/2() ()/2()iiiiii iiiiiiVAATTV D VVTTD Where, 1,iiAAis acceleration of desired time and previous time of one step before desired time. 1,iiVV is velocity of desired time and previous time of one step before desired time. 1,iiDD is displacement of desired time and pr evious time of one step before desired time. 1,iiTT is desired time and previous time of one step before desired time. D.1.5 Dynamic Stiffness To make the plot of stress vs. displaceme nt derived from accelerometer for dynamic soil particle movement, there is the assumption (i.e., the displacement should be occurred when the compactor is located on above the instrumentation. At that time, the stress should be peak). The way to reduce data for dynamic stiffness derived was with matching the displacement derived from accelerometer w ith the displacement from LVDT. With assumption, the velocity derived from accelerometer around peak stress was used for reducing with trial and error for matching the displacement from between LVDT and accelerometer.

PAGE 77

65 D.2 Using Worksheet after 3 Passes with Vibratory Padfoot Roller in Section 2 D.2.1 Raw Data Table D-3. Example of Raw Data

PAGE 78

66 D.2.2 Reduced Data Table D-4. Example of Reduced Data

PAGE 79

67 Figure D-1. Stress from Stress Cell vs.Time

PAGE 80

68 Figure D-2. Displacement from LVDT vs. Time

PAGE 81

69 Figure D-3. Acceleration vs. Time

PAGE 82

70 APPENDIX E RESULTS OF SSG Table E-1. SSG Data for Section 1

PAGE 83

71 Table E-2. SSG Data for Section 2 Table E-3. SSG Data for Section 3

PAGE 84

APPENDIX F RESULTS OF FWD

PAGE 85

73 Figure F-1. D0 Impulse Sti ffness Modulus for Section 1 0 100 200 300 400 500 600 1.011.021.031.041.051.061.071.081.091.10 StationsD0 ISM, kips/inch 1st 6" Lift 2nd 6" Lift Subgrade

PAGE 86

74 Figure F-2. D0 Impulse Sti ffness Modulus for Section 2 0 100 200 300 400 500 600 700 800 900 1.011.021.031.041.05 1.061.071.081.091.10 StationsD0 ISM, kips/inch 12 Lift Subgrade

PAGE 87

75 Figure F-3. D0 Impulse Sti ffness Modulus for Section 3 0 200 400 600 800 1000 12001.011.021.031.041.051.061.071.081.091.10 StationsD0 ISM, kips/inch 12 Lift Subgrade

PAGE 88

APPENDIX G RESULTS OF ADCP

PAGE 89

77 Table G-1. Slope Summary

PAGE 90

78 Table G-2. DCPI Summary

PAGE 91

79 Figure G-1. Depth vs. Number of Blows for Section 1 0 5 10 15 20 25 020406080100120140160180Number of BlowsDepth (inches) Location 1 Location 2 Location 3 Location 4 Location 5 Location 6 Location 7 Location 8 Location 9 Location 10

PAGE 92

80 Figure G-2. Depth vs. Number of Blows for Section 2 0 5 10 15 20 25 020406080100120140160180200Number of BlowsDepth (inches) Location 1 Location 2 Location 3 Location 4 Location 5 Location 6 Location 7 Location 8 Location 9 Location 10

PAGE 93

81 Figure G-3. Depth vs. Number of Blows for Section 3 0 5 10 15 20 25 050100150200250300350400Number of BlowsDepth (inches) Location 1 Location 2 Location 3 Location 4 Location 5 Location 6 Location 7 Location 8 Locaation 9 Location 10

PAGE 94

82 LIST OF REFERENCES Forssblad, L., 1965, Investigations of Soil Compaction by Vibration Acta Polytechnica Scandinavia, No. Ci-34, Stockholm. Forssblad, L.,1977, Vibratory Compaction in the Construction of Roads, Airfields, Dams, and Other Projects, Research Report No. 8222, Dynapac, S-171, No. 22, Solna. Parsons, A.W., Krawczyk, J. and Cross, J.E., Mar.1962, An I nvestigation of the performance of an 8.5 ton Vibrating Ro ller for the Compaction of Soil Road Research Laboratory Note. LN/64/ AWP.JK.JEC. Seed, H.B., and Chan, C.K., 1959, Stru cture and Strength Ch aracteristics of Compacted Clays, Journal of the So il Mechanics and Foundations Division, American Society of Civil Engineers, Vol.85, No. SM5, pp.87~128. Townsend, F.C. & Anderson, B., 2004, A Compendium of Ground Modification Techniques, Research Report BC-354, pp. 16~60. Florida Department of Transportation (FDOT). Turnbull, W.J., and Foster, C.R., 1956, S tabilization of Materials by Compaction, Journal of the Soil Mechanic s and Foundations Division, American Society of Civil Engineers, Vol. 82, No.SM2, pp.934-1~934-23. Yoo, T.S., 1975, A Theory for Vibrator y Compaction of Soil, Ph.D dissertation University of New York, Buffalo, NY.

PAGE 95

83 BIOGRAPHICAL SKETCH Jeongsoo Ko was born in Gwangju, South Korea. He spent his childhood in that beautiful city where he finished primary, middle, high school, and university, except during military service. He was accepted to study civil engineering at Chosun Univerity, Gwangju, South Korea in 1994. He earned the degr ee of Engineering Bachelor in March 2002. During undergraduate school, he did 26 months of military service at the border between South and North Korea. He realized that his knowle dge was far from enough to deal with real work problems. So he decided to go abroad for advanced education. He was accepted by the Civil and Coastal Engineering Department at the University of Florida and went to the U.S. in Jury 2003. He had studied and worked on thick lif t compaction with Dr. McVay for 1 year. Including this period, I spent the whol e 18 months to study his background in Geotechnical Engineering. He earned his ma sterss degree in August 2005. He plans to continue there for his Ph.D.


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Title: Evaluating Limerock-Base Thick Lift
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Copyright Date: 2008

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EVALUATING LIMEROCK-BASE THICK LIFT


By

JEONGSOO KO
















A THESIS PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
MASTER OF ENGINEERING

UNIVERSITY OF FLORIDA


2005

































Copyright 2005

by

Jeongsoo Ko

































To my family, especially my lovely wife.















ACKNOWLEDGMENTS

I would like to express my sincere gratitude to Dr. Michael C. McVay for the

opportunity to do this project and for my invaluable guidance during the research. I also

wish to express my thanks to Dr. Frank C. Townsend and Dr. Bjorn Birgisson for

teaching the basic concept on which my study is based. I appreciate their time and efforts

they devoted to serving on my supervisory committee.

I also wish to express my gratitude to Dr. Putcha of the FDOT for his financial

support. For supporting installation and measuring of soil properties, I also thank to Mr.

Werner of Ardaman & Associates, Orlando, FL and the Florida State Materials Office. I

deeply appreciate the interest and overall support received from Mr. Tim Relke from

District 2 and Mr. Jack Banning.

I thank the geotechnical group of the Civil and Coastal Engineering Department, at

the University of Florida. I would like to say thank Scott for his help for recommending

this project and for my friendship with Zihong and Lila.

Finally, I thank my wife, Yookyeong for her patience, encouragement, and sacrifice

for 2 years of my graduate study, and I thank my family for their endless love and support.















TABLE OF CONTENTS
page

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

LIST OF TABLES ............... ...................................... ... .................... vii

LIST OF FIGURES ......... ....... ...................... .......... ...... ix

ABSTRACT .............................. ........................ xii

CHAPTER

1 IN TR O D U C TIO N ............................................................ .. ..................... 1

1 .1 G en eral ................................................................................................. . 1
1.2 O bjectiv e .............................................. 2
1.3 Scope..................................................... . 3
1 .3 .1 T a sk 1 ................................................................................... . 3
1.3.2 T ask 2 ............................................................. . 4
1.3 .3 T ask 3 ............................................................. . 4

2 COMPACTION BACKGROUND .......................................................................5

2.1 Field Vibratory Compaction ..................................... 5
2.2 Strength, M oisture and Compactive Effort.................................. ............... 6
2 .3 Intellig ent C om p action .................................................................................... 10

3 TEST SITE AND INSTRUMENTATION ...................................... ...............14

3.1 M materials, Site Layout, and Equipm ent ...................................... ............. ..14
3.2 Embedded Instrumentation .................................. ...............................15
3 .2 .1 A ccelerom eters ................................. ......... .... ....... ................ 17
3 .2 .2 L V D T .................................................................................................... 1 8
3.2.3 Stress C ell ................................................................... .......18

4 RE SU LTS AN D D ISCU SSION ................................................. ........................ 20

4.1 Stress M easurem ents .................................. .........................................20
4.2 Com active Energy vs. D epth ......................................................................... 22
4.3 LVDT Strains & Measured Densities................................. ......... ..............26
4.4 Measured Dry Densities and Moistures vs. FDOT Specified Values ..................30









4 .5 B a se S tiffn e ss ................................................................................................... 3 3
4 .6 B ase Strength v s. D epth ............................................................... ....................38

5 SUMMARY, CONCLUSION AND CONCLUSIION............................................44

5 .1 S u m m a ry .......................................................................................................... 4 4
5.2 Conclusion .................................................................... ........ 46
5 .3 R ecom m en nation .......................................................................... ...................4 7

APPENDIX

A SIEVE AN ALY SIS RESULTS ......................................................... ............... 48

B MOISTURE CONTENT MEASURED BY NUCLEAR DENSITY PROBE........... 58

C OVEN MOISTURE CONTENT RESULTS .............................................................62

D D A T A R E D U C IN G ........................................................................... ....................63

D .1 Calculation for Reducing Data ........................... ....... ............................... 63
D 1.1 Stress ................................................................................ .. .. 6 3
D 1 .2 S train .................................................................................. 6 3
D 1.3 A acceleration ................. .... ................. ... ............. ............ 64
D. 1.4 Velocity and Displacement from Acceleration Data..............................64
D. 1.5 Dynamic Stiffness..................... .......... ..... .....................64
D.2 Using Worksheet after 3 Passes with Vibratory Padfoot Roller in Section 2......65
D .2 .1 R aw D ata .................................................. ................ 6 5
D .2.2 Reduced D ata.................... ............... ......... ....... 66

E RE SU LTS O F SSG ....................... ....................... ......... ... ........70

F R E SU L T S O F FW D ......................................................................... ....................72

G R E SU L T S O F A D C P ......................................................................... ...................76

LIST OF REFEREN CES ...................................................................... ............... 82

BIOGRAPHICAL SKETCH .. ....................................... ............. 83















LIST OF TABLES


Table page

4-1. Measured Dry Densities from Nuclear Device within Section 1 ............................29

4-2. Measured and Computed Dry Densities from Nuclear Device within Section 2.......31

4-3. Measured and Computed Dry Densities from Nuclear Device within Section 3.......32

4-4. FWD Mean and Standard Deviation on Each Section ............................................36

4-5. SSG Mean and Standard Deviation on Each Section....... ..................................38

4-6. Summary ADCP Results for Section 1.............................. ......................... 41

4-7. Summary of ADCP Results for Section 2 ...................... ................... ...............41

4-8. Summary of ADCP Results for Section 3 .................................................41

5-1. Test Sections and C om pactors......................................................... ............... 45

A -1. Sam ple # vs. L location #.................................................. ............................... 48

B-1. Data from Nuclear Density Measurement for Section 1........................................59

B-2. Data from Nuclear Density Measurement for Section 2.........................................60

B-3. Data from Nuclear Density Measurement for Section 3.........................................61

C-1. Data from Oven Moisture Measurement ....................................... ............... 62

D -1. Factor for Reducing of Strain D ata....................................... ......................... 63

D-2. Factor for Reducing of Acceleration Data.................................... .....................64

D -3. E xam ple of R aw D ata ............................................................................... ........ 65

D -4. Exam ple of Reduced D ata ...................................................................... 66

E -1. S SG D ata for Section 1 ..................................................................... ...................70









E -2. SSG D ata for Section 2 ............................................ .................. ............... 71

E -3. SSG D ata for Section 3 ..... ............ ... ................ ................ ............................... 71

G -1. Slope Sum m ary ...................... .. ...................... .... ....... ............. 77

G-2. D CPI Sum m ary............................... .. ........... .. ............78

















































viii















LIST OF FIGURES


Figure page

2-1. Relationships between Density, Compaction Energy and Strength vs. Moisture
Content. A) Strength vs. Water content for 25% Strain. B) Strength vs.
Water content for 5% Strain. C) Dry Density vs. Water Content (Seed & Chan,
19 59) .... ..... ............................................................................ 8

2-2. Relationships between Strength Parameter (CBR) vs. Moisture Content and
Density vs. Various Compaction Energies (Turnbull & Foster, 1956)....................9

2-3. The LBR vs. Moisture Content Compacted to Dry Density of 123pcf.................10

2-4. Conventional Vibratory Roller................................ .......................... 11

2-5 V ariocontrol V ibratory R ollers........................................... ........................... 12

2-6. One Dimensional Model of Compactor and Subsoil..............................................12

3-1. Lim erock G rain Size D distribution ........................................ ........................ 14

3-2. Plan Views of Test Strips at SR-826 ......................................................... 16

3-3. T est Section C om pactors ........................................................................... ...... 17

3-4. Section 1 Instrum entation Two 6-inch Lifts.................................. ... ..................18

3-5. Section 2 Instrumentation 12-inch Thick Lift ....................................... .......... 19

3-6. Section 3 Instrumentation 12-inch Thick Lift ....................................... .......... 19

4-1. Measured Stress as Function of Time Due to a Passing Vibratory Roller ..............20

4-2. Stress vs. Number of Passes in two 6-inch lift on Section 1 ..................................21

4-3. Stresses vs. Number of Passes in the 12-inch Lift of Section 2 .............................23

4-4. Stresses vs. Number of Passes in the 12-inch Lift of Section 3 ..............................24

4-5. Stress vs. Particle Displacements at Bottom of Section 1 during 4th Pass ...............25

4-6. Forces on the drum and associated loading loop .............. ...................................25









4-8. Stress vs. Displacement after 7th pass on Section 3...............................................27

4-9. Density Calculations with Depth........................................................................ 28

4-10. Strain from LVDT vs. Dry density from NDP for Section 1 ..............................29

4.11 Strain from LVDT vs. Dry density from NDP for Section 2..............................31

4-12 train from LVDT vs. Dry density from NDP for Section 3...................................32

4-13. Dry densities and Moisture Contents in Section 1 ..............................................33

4-14. Dry Densities and Moisture Contents in Section 2..............................................34

4-15. Dry Densities and Moisture Contents in Section 3............................................35

4-16. Stiffness Measured with FWD in All Sections....................................................36

4-17. Stiffness measured by SSG in All Sections......... .............................38

4-18. Stiffness from FWD & SSG vs. Dynamic Modulus from Vario-System ..............39

4-19. Stiffness and Evib Moduli as Function of Depth and Number of Passes ................40

4-20 ADCP Data for Section 1 After 2nd Layer...................... .............................. 41

4-21. A CD P D ata for Section 2 .............. .................................. .............................. 42

4-22. A CD P D ata for Section 3 .............................................. ............................. 42

4-23. Comparison ADCP Data from Section 1 and 2....... .......................................43

4-24. Comparison ADCP Data from Section 1 and 3 ............................................... 43

A -1. Sieve A analysis for S1 and S2...................................... ............... ............... 49

A -2. Sieve A analysis for S3 and S4...................................... ............... ............... 50

A -3. Sieve A analysis for S5 and S6 .......... ................ ............................... .. ..............51

A -4. Sieve A analysis for S7 and S8...................................... ............... ............... 52

A -5. Sieve A analysis for S9 and S10.......................................... ........................... 53

A-6. Sieve Analysis for S11 and S12............... ................................... ....................54

A -7. Sieve A analysis for S13 and S14........................................ ........................... 55

A -8. Sieve A analysis for S15 and S16........................................ ........................... 56









A -9. Sieve A analysis for S17 and S18........................................ ........................... 57

D -1. Stress from Stress Cell vs.Tim e........................................ ........................... 67

D-2. Displacement from LVDT vs. Time.................. ... ..... ................. 68

D -3. A acceleration vs. T im e .............................................................................. .... ........69

F-1. DO Impulse Stiffness M odulus for Section 1 ................................ .................73

F-2. DO Impulse Stiffness M odulus for Section 2 ................................. ............... 74

F-3. DO Impulse Stiffness M odulus for Section 3 ................................. ............... 75

G-1. Depth vs. Number of Blows for Section 1........................... ..................79

G-2. Depth vs. Number of Blows for Section 2...................................80

G-3. Depth vs. Number of Blows for Section 3............... ........................................... 81















Abstract of Thesis Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Master of Engineering

EVALUATING LIMEROCK-BASE THICK LIFT

By

Jeongsoo Ko

August 2005

Chair: Michael C. McVay
Major Department: Civil and Coastal Engineering

Current Florida Department of Transportation practice allows maximum lift

thickness of 6-inch with no specific controls on moisture. Furthermore, most limerock

base courses are compacted with either single or dual steel roller with vibratory dynamic

forces less than 50,000 lbf The object of our study was replacement and compaction of a

single 12-inch limerock-base lift using a compactor with a 63,000 lbf pad-foot roller and

an 85,000 lbf heavy smooth roller, instead of two conventional 6-inch limerock-base lifts.

To judge achievement of the replacement, we compared results from one 12-inch and two

6-inch limerock-base lift. The single 12-inch limerock-base lift compaction in

construction can be achieved under specific conditions based on sufficient strength and

stiffness compared with two conventional 6-inch limerock-base lifts.














CHAPTER 1
INTRODUCTION

1.1 General

Mechanical compaction of earthen materials has been used for thousands of years.

In the US, static/dynamic smooth, pad or sheep-foot rollers are common in construction

of roadway embankments, bases, dams, and so on. Generally, field compaction is

controlled through dry density and water content established in the laboratory (e.g.,

Proctor test). In the latter, multiple layers of soil are compacted with constant energies at

different moisture content to identify the highest dry density. The higher the dry density

and the lower the water content of the deposit, the higher the expected strength and

stiffness of the compacted placed backfill.

In the field, the contractor has many ways to achieve a specific dry density for a

specific material and gradation:

* Different compaction Equipment vibratoryy, static, smooth, pad, etc.)

* Number of passes

* Lift thickness

* Moisture content

* Stiffness of subgrade soil and base course materials

In Florida, most if not all limerock-base courses (FDOT Specification 200) have a

maximum particle size of 3" and minimum percentage of fines (i.e., passing 200 sieve) of

35%. Current FDOT practice (Specification 200) allows maximum lift thickness of 6-

inch with no specific controls on moisture. Generally, moisture contents vary widely









based on location (5% south Florida to 14% central Florida and north) of mine-material,

humidity, and so on. Most, if not all limerock-base courses are compacted with either

single or dual steel rollers with vibratory dynamic forces less than 50,000 lbf.

Of strong interest is the feasibility of compacting thicker lifts (e.g., a single 12-inch

lift instead of conventional two 6-inch lifts for roadway base courses). The compacting

single 12-inch lift appeals to contractors because it reduces costs (especially time). For

two conventional 6-inch lifts, the contractor must transport the material, grade it, compact

it and perform quality control (density, moisture, etc.) twice vs. once with a 12-inch lift.

1.2 Objective

Our object was placement and compaction of a single 12-inch limerock-lift instead

of two 6-inch lifts over competent subgrade. We focused on compaction equipment

readily available to contractors, and materials with no special gradation. Successful

placement was judged on similarities of stiffness and strength between the thick lift (12-

inch) and two 6-inch lifts constructed using the same material, conditions, and subgrade

conditions.

To identify the appropriate compaction equipment, passes, moisture, and so on, we

used instrumentation in the base (i.e., stress cells, LVDTs, and accelerometers). The

LVDTs were used to validate densities measured with nuclear devices, and the stress

cells and accelerometers measured stiffness and energies within the compacted fill.

Since thick lift limerock compaction has had minimal application in Florida, we

decided to select a site, materials, and equipment with the potential for success. The

following were selected: 1) vibratory pad foot roller or heavy smooth wheel vibratory

roller; 2) well graded limerock with limited fines at moisture content on dry of optimum

(higher stiffness & strength) and 3) stiff/strong subgrade (LBR > 100).









1.3 Scope

The site selected for thick lift compaction study by the FDOT was SR 826 in

Miami Florida, District 4. Located near Miami International Airport, SR 826 has Oolitic

limestone near the surface (i.e., a strong subgrade, LBR>100), with ongoing placement of

conventional 6-inch limerock lifts that were well graded, low fine content, and moisture

content varying from 5 to 9% from the source (i.e., dry of optimum).

After discussion with FDOT, Ardaman & Associates and UF personnel, we decided

to compact three 100-foot test sections. The first section was to be compacted by

conventional means (i.e., two 6-inch lifts, using a typical smooth-wheel vibratory

compactor). The second 100-foot test section used a 12-inch lift, and the vibratory pad-

foot roller (55,000 lbf). The third 100-foot test section also used a 12-inch lift, but

compacted with a heavier smooth-wheel vibratory compactor using intelligent

compaction control. The latter roller can measure soil stiffness, and can vary the applied

vertical dynamic force depending on the preset stiffness (modulus).

For all three sections, we measured vertical stress, acceleration, and strain for each

pass of the roller. We measured nuclear density and moisture content after three or four

passes of the compactor on each section. To measure strength and stiffness, we used

dynamic cone penetration, falling weight deflectometer, and the soil stiffness gauge test

at ten locations along each section. In addition, multiple bag samples were collected both

pre and post compaction from each section, and sieved to identify particle breakage due

to compaction. The following three tasks were completed by FDOT, Ardaman &

Associates, and University of Florida to complete the scope of services.

1.3.1 Task 1

The FDOT District CEI performed laboratory proctor results identifying optimum









moisture content and dry densities. The FDOT State Materials Office personnel

performed Falling Weight Deflection (FWD) Testing, Automatic Dynamic Cone

Penetrometer Testing (ADCPT), Soil Stiffness Gage (SSG) testing, bag sampling, and

laboratory sieve analysis of pre and post compacted limerock for the three test sections.

1.3.2 Task 2

Ardaman and Associates placed the instrumentation at multiple depths in each test

section, recorded the data for each pass of compactor, and collected nuclear density, and

moisture measurements for each test section.

1.3.3 Task 3

University of Florida collected all of the measured data (stresses, strains,

accelerations, FWD, ADCP, SSG, etc.) for each section, reduced it (stiffness, moduli,

energies, etc.) and compared sections (i.e., 6-inch lift vs. 12-inch).














CHAPTER 2
COMPACTION BACKGROUND

2.1 Field Vibratory Compaction

Typical vibratory compaction equipment includes hand-held plates (i.e., tampers),

and single, and multiple-wheels drum rollers. Our study tested vibrating smooth and pad-

foot rollers.

The basic concept of vibratory roller is to use unbalanced weights to develop

sinusoidal forces. In addition all vibratory rollers (i.e., towed, self-propelled, and/or

tandem) have the static weight (motor, frame, etc.) separated from the vibratory mass

through shock absorbers. The total force imparted to the ground is given in Eq. 2-1. The

first term is inertia (dynamic) force due to the static weight of the drum. The second term

is the varying dynamic force due to the rotating masses within the drum, and the third

term is the static weight of both the drum and the rotating masses. Note that the second

term is a function of the frequency, f, of the rotating masses.


F, = md Xd ++ tm r 2 cos( Qt) + (mM + md) g

where
md= mass of the drum (kg)
Xd = vertical displacement of drum (m)
xd = acceleration of drum (m/s2)
mf = mass of the frame (kg)
mu = unbalanced mass (kg)
ru = radial distance at which mu is attached (m)
muru = static moment of the rotating shaft (kg.m)
Q=27f
t = time elapsed (sec)
g = acceleration due to gravity (m/sec2)


(2-1)









f = frequency of the rotating shaft (Hz)

Generally, the contribution from the second term is much less than that from the

first and third terms. For instance, Forssblad (1965) studied the effect of the vibratory

masses on a vibratory roller's compaction. By adding 24% of the total roller weight to the

frame, a considerable increase in a soil's compacted density occurred; however, a similar

change in the drum's weight did not result in an analogous increase in soil density.

Parsons et al. (1962) focused on accelerating of the vibratory motion (i.e., xd in Eq.

2-1). Besides increasing the dynamic force (Eq. 2-1), Parsons et al. found little effect in

typical 6 to 9-inch thick lifts that could not be accomplished with more passes of the

roller.

Yoo (1978) improved field instrumentation by using inductance coil strain gages

for field compaction studies. Their experiments also varied compactor weight and layer

thickness for gravel-sand mixtures compacted dry (4%) of optimum moisture content.

Both 12-inch and 36-inch thick fills were compacted under various energies and moisture

content. They concluded that the maximum compact layer thickness should be limited to

12-inch (vs. 36-inch) from stiffness and densities measurements with depth. Similarly,

WES (USACE-WES, 1976) carried out compaction on lean clay (PI=13) with various

water contents using a sheep-foot roller. Based on that study, they recommended a

limitation of lift thickness of 7-inch.

2.2 Strength, Moisture and Compactive Effort

Even though field compaction is generally controlled by dry density and moisture

contents, the stiffness and strength of the placed backfill are the properties of interest.

For instance, deflection, rutting, and bearing failure of a base course control its design









(i.e., AASHTO 2002). Since stiffness and strength measurements are difficult to perform

on a routine basis in field, they have been equated to a materials density and moisture

content.

Seed and Chan (1959) were one of the first to study the relationship between

material strength, compaction effort and moisture for fine-grained soils. Their

experiments were performed with Harvard Compaction setup (62.4 cm3 specimen, 0.5-

inch compacting rod with variable spring stiffness). Figure 2-1 shows the change in dry

density (bottom), small strain stiffness (middle) and large strain stiffness (top figure) vs.

moisture content for different compaction energies. Evident from the figure, stiffness, and

density increase with compaction energy for a moisture content dry of optimum. Note the

significant reduction in stiffness for a given compactive effort as the moisture content

passes wet of optimum.

Tumbull and Foster (1956) studied the influence of moisture and compactive effort

on granular soils in Figure 2-2. Instead of performing triaxial compression, they

conducted California Bearing Ratio (CBR). Similar results as shown in Figure 2.1 are

seen in Figure 2.2. Ping et al (1996) has suggested a correlation of 1.25 between the

Florida Limerock Bearing Ratio Test (LBR) and CBR results.

The FDOT State Materials Office (SMO) compacted the Florida limerock to meet

LBR requirements. As part of this research, SMO agreed to compact additional

specimens to a constant dry density (123 pcf) at different moisture contents with

subsequent LBR testing. Figure 2-3 shows variation of LBR value with moisture content

for both soaked and un-soaked samples. Evident is the higher stiffness/strength of the un-

soaked samples dry of optimum (10.5% from standard proctor). The latter agrees with














IrrPngth (stress reqilire to icauRs
25% strain) vs. water content


Unconsolidatwd- undrained tests
C .nf.i.io penurI 10 kyi'C;111


10 12 14 16


12r-


4 1


2

0
10 12


18 20


22 24 26


Strength (stress required to cause
5% strain vs, water content




Layers Tarnis pef Foot
layer pressure
L 7 15 276 rps
7 15 136 psi
o 7 15 65 psi


16 18 20
Molding water content (%)


Figure 2-1. Relationships between Density, Compaction Energy and Strength vs.
Moisture Content. A) Strength vs. Water content for 25% Strain. B)
Strength vs. Water content for 5% Strain. C) Dry Density vs. Water
Content (Seed & Chan, 1959)


-" 1%



a
I{














75





? 5






20



1t5












.,b.

90
10 20 25
Water content ',.

Legend
'7 55 blows (er laver
0 26 blows per layer

1 1 blows per layer
S---6 6 blows per layer

NorT, 10 Ib hammnrr,18"' drop
,'n'diti.ld Proctorl


Figure 2-2. Relationships between Strength Parameter (CBR) vs. Moisture Content and
Density vs. Various Compaction Energies (Turnbull & Foster, 1956)


"-""'1










Seed & Chan, and Turnbull & Foster that compaction dry of optimum for a specific dry

density would ensure a higher strength and stiffness.


1000 1 r


at
m 100








10
10


TEST #3
100% MIX
UNSOCAED
LBR



- TEST #4
100% MAX
SOCED
LBR


8 9 10 11 12 13

MOISULRE(

Figure 2-3. The LBR vs. Moisture Content Compacted to Dry Density of 123pcf

2.3 Intelligent Compaction

To perform thick lift placement, one of the Compactor manufacturers, Bomag,

recommended the use of their Intelligent Compaction Control (ICC) devices.

Conventional vibratory steel wheel rollers, Figure 2.4 employ rotating eccentric masses

to develop vertical dynamic forces, Eq. 2.1. Moreover, circular motions of the masses are

aligned such that the dynamic forces are always vertical. In addition, conventional

vibratory rollers operate at either high frequency and low amplitude or low frequency and

high amplitude to prevent damage to the equipment.

Recently, a number of manufacturers have implemented more control or feedback


-- f --___ __ -------------



____________ -.__.^












hl h
bw ampltude


-., '5..,. .*," i^ JWL "





Application Compaction principle Application
ihn ia-.i) s static pressure and thick layers
granular materials dynamic energy granular and cohesive materials
granular bases Key parameters cement bound materials
overlay compactioon n static linear load subbases
thick granular layers *. ,rr ring mass embankments
injitude dams
frequency
Figure 2-4. Conventional Vibratory Roller

between the instrumentation (accelerometer) on the compactor's drum, and the force

delivered to the ground. One such unit is Bomag's variocontrol Roller, shown in Figure

2.5. Assuming a one-degree of freedom model for the compacted backfill, Figure 2.6, the

static stiffness, kB, of the base is computed from


F, = kB d + d xd (2-2)

where
kB = stiffness of soil (F/L)
Xd = vertical displacement of soil
dB= damping coefficient (value of 0.2 assumed)
d = velocity of soil mass (measured at drum)

Next using Lundberg's (1939) work, the Young's Modulus, Evib of the compacted

soil is found from the soil stiffness, kb, Eq. 2.3:

E Lz
kB = L (2-3)

2(1 02) 2.14+- ln 2)16( n
2 1 )16(m,+md)Rg












H


low dynamic energy
due to horizontally
directed vibrations


-I *4 t Q 0 j. -
*'-.. N

Compaction effect high dynamic energy
DiaJ.,Jv.ei 1 rand dynamic energy, due to .~-i, I. ally
the compaction effect is automatically directed vibrations
adapted to : ii pacrbi;rbi rI of material,
layrr ri' ickra..s and subbase.

Applications: all soil types,
granular bases and subbases.
Figure 2-5 Variocontrol Vibratory Rollers


"x x lumped
halve' parnmeter Y
Model
Figure 2-6. One Dimensional Model of Compactor and Subsoil


where
L = length of roller
R = radius of roller
v= poisson's ratio of the soil

The variocontrol unit in the manual mode will automatically display the Evib

measurements of the compacted base material, which may be used as quality assessment.

In the automatic mode, the user identifies a target Evib value as potential specification; the

unit then alters the orientation of rotating masses, automatically directing more or less






13


dynamic force into the ground. One of Bomag's variocontrol units, BW 225BV-3 was

tested at the SR-826 site.
















CHAPTER 3
TEST SITE AND INSTRUMENTATION

3.1 Materials, Site Layout, and Equipment

A typical grain size distribution curve for the compacted Florida limerock at SR-826 is

shown in Figure 3-1. AASHTO classification of the material is A-i-a, or GW within the

Unified Soil Classification System. Grain Size distributions for all of test sections are

given in Appendix A as reported by the State Materials Office. Laboratory modified

proctor analysis revealed a maximum dry density of 131 pcf and an optimum moisture

content of 9%. FDOT Standards Specification 200 required a final placed dry density of

128.4 pcf (i.e., 98%) for successful base construction.




100
90 -- ---- --- --

80 -
70----- ---

w 60- -- -----
S50
40 --- -----
30--- -
20- ----
SS-4
10 -

0
100.0 10.0 1.00 0.10 0.01
DIAMETER (mm)
Figure 3-1. Limerock Grain Size Distribution

Figure 3-2 shows the plan view for all three-test sections at SR-826. All Sections

were placed over preexisting limerock with LBR values above 100.









Section 1, located from stations 227 to 228, at the northeastern quadrant of the site

had two conventional 6-inch lifts placed over existing subgrade. The section was

compacted with a Bomag BW 211D-3, a smooth wheel vibratory compactor with a

maximum vertical dynamic force of 53,000 lbf, Figure 3-3

Sections 2 and 3 on the eastern portion of the site, involved placing loose limerock

with dump trunks, and spreading with a dozer to a depth of approximately 13-inch (i.e.,

compacted 12-inch) prior to compaction. Section 2 was compacted with a Bomag BW

213PD-3 pad foot roller with maximum dynamic force of 62,000 lbf and a pad height of

approximately 4 inches. This device was selected to ensure higher stresses, energies, etc.

deeper within the limerock (i.e., densification of the bottom 1/3 of the lift).

Section 3 was compacted with a new Bomag variocontrol unit, BW 225 BV-3.

The unit is the largest smooth wheel vibratory roller that Bomag manufactures, capable of

developing 85,000 lbf of dynamic force. As identified in Chapter 2, the unit either

measures the Modulus, Evib, of the layer (manual mode) or will adjust the dynamic force

imparted to the base to obtain a preset Evib values with travel. The unit was run in both

modes for this effort.

Figure 3-2 shows the 10 locations of the of the Falling Weight Deflectometer

(FWD), Soil Stiffness Gage (SSG), and Automatic Dynamic Cone Penetrometer Tests

(ADCPT) which were preformed at the finish of compaction for each test section by the

State Materials Office Personnel. Figure 3-1 also shows the location of buried

instrumentation, discussed in the next section.

3.2 Embedded Instrumentation

To evaluate the compaction process with depth, instrumentation was placed at 1/3

points within the base layer. Since one of the compaction units was a pad foot roller with











228+00


Secti~o 1
w/BCMAG W 211D-3


Location #
#10?





b #
#86




g#4


*#1


227+00


O
*


Tesum iotai 1 LocatiX

Test Locationf FfS) S= DCP


North


-East


Section 3
w/BOMdAG BW 225B-



(


Section 2
W/ BCMAG BW 213PD-


South


at the bottom of each 1/3 locations.


Location #
-#10-









9#2
0#1



3
#,




# tg


226+00
I West


Figure 3-2. Plan Views of Test Strips at SR-826
the potential of damaging the instrumentation, it was decided to locate all the equipment



































Figure 3-3. Test Section Compactors

Of interest are the stresses, energies, stiffness, and strains with depth as compared

to the observed laboratory response (i.e., proctor, LBR, etc.). For instance, it is expected

that dry densities found in the laboratory would be achievable in the field if similar

energies (compaction) were applied. In addition, comparisons of density at the bottom of

the thick lift computed from nuclear density device vs. measured strains are of interest

(i.e., verification). To accomplish the latter the following instrumentation was installed:

3.2.1 Accelerometers

Of interest are displacements as a function of dynamic vibrations due to the roller.

Initial attempts used velocity sensors like those employed in seismic geophones.

Unfortunately, the latter generally do not provide the necessary response times.

Subsequently, it was decided to employ accelerometers and integrate the response to










obtain displacements. To provide accurate, repeatable information, DC accelerometers of

the capacitive resistance type were employed (i.e., capable of OHz or Ig response). The

devices were attached or placed in the vicinity of the stress cells.

3.2.2 LVDT

Initially, it was planned to read the LVDTs only after a pass of compactor.

However, from the analog nature of the device and with a sufficiently sampling

frequency with the data acquisition system, the relative displacements or strains may be

obtained during the compaction process. To maintain the location of the devices, as well

as their orientation, the LVDTs had 3-inch plastic plates attached to the top of the LVDT

housing as well end of sensing rod.

3.2.3 Stress Cell

To measure the vertical stress as a function of compactor motion, 12-inch

diameter stress cells were employed. The sensing face was filled with incompressible

fluid and the pore transducer was attached 18-inch from the sensor with steel lines.

Ardaman and Associates calibrated the devices in the laboratory for Florida limerock.


Backward
<--...d.- Af


A FORWARD
Prwd BOMAG BW 211D-3 I
PLAN VIEW LIMEROCK SURFACE
6" Layer (Top 6") LVDTStram Senr 8" Layer (Top 6")
Acelerome LVDT' Strain r s7.
S r ------- -------y--- -- -
Stress Cell Accelerometer 4"
6i- Laye/rIBotom) T 1 l.B" lotm) (B.tto S61C) *I 12"

SEC 3ON S"A" SEC1-inch LB'


Figure 3-4. Section 1 Instrumentation Two 6-inch Lifts














Backward

BOMG BW 213PD-3 A



Forward A B

PLAN VIEW


A T trami SesOr
Stress Cell





SECTMN"A"


G BW FORWARD
BOMAG BW 213PD-3


SECTION '


Figure 3-5. Section 2 Instrumentation 12-inch Thick Lift


Forward
lj='- l [ --
BOMAG BW 225D-3 A



Backward A

PLAN VEW



Accelerometer LVDT Strain Sensor
Stress Cell




SEC72ON "A"


FORWARD

BOMAG BW 225[-3


LIMEROCK SURFACE


SECTION "'


Figure 3-6. Section 3 Instrumentation 12-inch Thick Lift















CHAPTER 4
RESULTS AND DISCUSSION

4.1 Stress Measurements

Typical recorded vertical stresses as a function of time due to a passing vibratory

roller is shown in Figure 4-1. Each peak represents a rotation of the vibratory mass,

which is happening at approximately 30 Hz (i.e., 6 peaks or rotations/0.2sec). Evident is

the buildup of stresses as the roller approaches the instrumentation, with the maximum

occurring with roller over the gage. Of interest are the stress changes vs. particle motions

(e.g., stiffness and energies), as well the peak stresses at various depths within the base

layer. Presented in this section are the peak (maximum) stresses as function of depth vs.

the number of passes.


80
70
60
50
40
30
20
10
n


*1 ______


2200 2400 2600 2800 3000 3200 3400 3600
TIME (milliseconds)
Figure 4-1. Measured Stress as Function of Time Due to a Passing Vibratory Roller

Figure 4-2 shows the peak stresses for Section 1 vs. pass # of the BW 21 1D-3.

The left side of the figure depicts the stresses at the middle and bottom (Figure 3-4) of the










first 6-inch lift for three passes. The right side of the figure show the stresses at the

middle and bottom of the first lift, as well as stresses at the bottom of the second 6-inch

lift for an additional 4 passes of the BW 211D-3 compactor. Evident from the figure is

the large difference in stresses between the middle and bottom (i.e., 3-inch vs. 6-inch) of

the 1st layer. However, with the placement of the second lift, there is little difference in

stresses from 6-inch to 12-inch as seen from the right side of Figure 4-2. The larger

difference in stresses at top vs. bottom was attributed to Boussinesq's equation and the

influence of the square of the depth below compactor on stress.



250 Ist 6 Inches flf 2nd 5 inches Lft ovr Ist 6 inches


Bo M
200







S100
-- -










0a1 2 3
5 0 ---------------- |----------------
-A-Bottom i- Middle




I of Two-Way Passes
Figure 4-2. Stress vs. Number of Passes in two 6-inch lift on Section 1

Figure 4-3 shows the maximum stresses at depths of 4.98, 9.12, and 13.5 inches in

the base for each pass of the BW 213PD-3 pad-foot roller (passes 1-3, and 5-6), and BW

211D-3 smooth wheel roller (pass 4, and 7-8) in Section 2. Note, that a pass (i.e., from 6









to 7) has two points (i.e., 6.5 and 7) which represent the compactor traveling from the

south to the north side of the site (i.e., 6.5), and subsequently back from the north to south

side (i.e., 7) of Section 2. Note passes, 4, 7, and 8 with the smooth wheel vibratory

roller were performed to ensure a smooth surface required in nuclear backscatter moisture

monitoring.

Figure 4-3 shows the stresses measured at all three instrumented depths were quite

similar for the pad foot versus the smooth wheel roller. The latter is attributed to the

larger contact area provided by the pads as well as their deeper penetration (i.e., 4-inch

high pads) vs. the smooth wheel roller. Also, note the similarity in stress (150 psi)

reported in Section 2 vs. Section 1 for 1st set of gages for the smooth wheel roller.

Figure 4-4 shows the maximum vertical stresses with depth (6.1, 9.4, and 13

inches) as a function of pass for the heaviest of the smooth wheel rollers (i.e., BW

225BV-3 (85,000 lbf). Apparent from a comparison of Figures 4-2 and 4-4, the stresses

between Sections 1 and 3, are approximately 1.6 times higher in Section 3 versus Section

1 due to increased dynamic force of the BW 225BV-3 (85,000 lbf) vs. BW 21 1D-3

(53,000 lbf). Also note however, the stresses variations observed in Section 2 for the

smaller smooth wheel roller (i.e., passes 7, 8) in Figure 4-3, do not occur in Section 3 for

the heavier smooth wheel roller. The latter may be due to particle crushing and larger

contact area under the compactor for the heavier roller (BW 225BV-3). Of interest are the

particle motions, which are occurring with the stress changes.

4.2 Compactive Energy vs. Depth

To identify soil particle dynamic movement, and subsequent energy transmissions,

accelerations were monitored with DC (0-100 Hz) piezo-capacitance instruments

attached to the tops of the stress cells at the three depth locations (Figure 3-4, 3-5, & 3-6).










250 I I
Vibratory smooth Rqller w/high Vibratory Smooth Roller w/hig
amplitude amplitude


200
Vibratory Pad Foot Roller Vipratory Pad Foot Ro ler



S150 I







I50
100 --------- / ---- 4 -- ^---







--Bott6m I- Middle -0- Top
0 L .
0 1 2 3 4 5 6 7 8 9
I of Two-Way Passes
Figure 4-3. Stresses vs. Number of Passes in the 12-inch Lift of Section 2

After integrating the accelerations twice, the particle displacements during a pass of a

compactor were obtained. Appendix D presents the data reduction process, as well as an

example of deformations as a function of time. Of interest is the relationship between

stress and deformation as a function of compactor motion. Figure 4-5 shows the typical

stress vs. particle motion at the bottom of Section 1 during the 4th pass of the BW 21 1D-3.

Each loop (ellipse) represents one complete rotation of the eccentric mass within

the roller (i.e., 30 Hz or 30 cycles/sec in Figure 4-1). The multiple loops with varying

peak stresses are a result of the roller either approaching or moving away from the

instrumentation. Note the similarities of Figure 4-5 and Bomag's force vs. displacement

measurement of the drum at the ground surface, Figure 4-6. As identified by Bomag,

Figure 4-6 shows the compression is a result of the compactor pressing down on the base,











450

400

350 '
00 ," \,\ I. "
300 I
-' / I \





150

100

50 -- -- Bottom I- Middle -- -Top


0 1 2 3 4 5 6 7 8 9 10
I of Two-Way Passes
Figure 4-4. Stresses vs. Number of Passes in the 12-inch Lift of Section 3

and the expansion (i.e., unloading) is due to the drum unloading the base. In the

unloading phase, the particle displacements are negative (i.e., in an upward direction. The

energy transmitted to the base for each rotation of eccentric mass within the roller is the

area within each loop, Figure 4-6.

Figure 4-7 shows the stresses vs. displacements at the top, middle and bottom of

Section 2 in the 5th pass of the BW 213PD-3 pad foot roller. Apparent is the similarities

of energies (i.e., areas) at the various depths within the 12-inch lift, with a slight drop at

the bottom. Interestingly, the slopes (i.e., stiffness) of the middle and bottom depths of

the lift are higher than the top. The latter may be attributed to the shape of the

compactor's contact area (i.e., pad, vs. the smooth wheel).

Figure 4-8 shows the stresses vs. displacements at the top, middle and bottom of

Section 3 in the 7th pass of the BW 225BV-3 smooth wheel roller. Evident is the










200

Bottom

156



100







0


-50
0.04 -0.02 0 0.02 0.04 0.06 0 08 0.1
Displacement(inch)
Figure 4-5. Stress vs. Particle Displacements at Bottom of Section 1 during 4th Pass



Soil contact force F8




0F'


PFcSeBo CCompression
/ Fp [loading i <
e effectively Expansion
A transferred (unloading)
energy

vibration path s

Figure 4-6. Forces on the drum and associated loading loop

similarities of energies (i.e., areas) at the top and bottom of 12-inch lift, suggesting

similar densities throughout the deposit. A comparison of energies (areas) between

Section 1 (Figure 4-5) and 3 (Figure 4-7), suggest higher densities changes or compaction

is being performed with one pass of the BW 225BV-3 vs. 21 1D-3. Also note that the











80
--- -Top ---Bottom a- Middle
70


XI!
60

50

S40

30

20

10

0

-10
0.04 0.03 0.02 0.01 0 -0.01 -0.02 -0.03
Displacement(inch)
Figure 4-7. Stress vs. Displacement after 5th Pass on Section 2

stiffness (i.e., slopes) of any loop is higher for the BW 225BV-3 (Figure 4-8), than the

slopes from Section 1 (Figure 4-5) with the passing of a Bomag 211. The latter should be

evident from Falling Weight Deflectometer (FWD) data discussed later.

4.3 LVDT Strains & Measured Densities

Of interest were the strains, which may be equated to density as function of depth within

the base course. FDOT's current nuclear density devices place the probe at depths of 6

and 12 inches, Figure 4-9. Due to the location of the source (various depths) and receiver


(surface), the density at 0 to 6-inch (yi) is accurate, as well the average 0 to 12-inch (Yt),


however, the density from 6 to 12-inch (72) is generally computed from the following


simple averaging assumption:


r, d, + rd2 d r (d, +d2) (4-1)










or solving for 72,


72 (d +d2)- 1 (d )
/2 d2 (4-2)


250

---- -Top B=-ottom
200



150







0





-50
-50 ---------
-0,05 0 0,05 0,1 0,15 0.2 0.25
Displacement(inch)
Figure 4-8. Stress vs. Displacement after 7th pass on Section 3

Knowing the moisture content, co, the average or individual dry densities (ydl ,

yd2) may be found as:



Yd ( (4-3)


For the device shown in Figure 4-9, the moisture content, co, is computed near the

surface (i.e., back scatter). For all calculations to follow, it is assumed that the moisture

content with depth is constant (i.e., co = co 1 = co2).

Given the uncertainty of the density calculations, it was of interest to check their















II
D1|








Figure 4-9. Density Calculations with Depth

values with other methods (e.g., strain measurements from LVDT). Knowing the original

spacing between a pair of LVDT plates (i.e., Figures. 3-4 ~ 3-6), the strain as a function

of compactor pass may be found as,

5 (change in spacing)
L (original spacing)


Next, assuming that the initial dry density (ydinitial) of the placed base material

is uniform, the final dry density (ydfinal) after a pass may be computed as,


d initial
7d _final (4-5)
1 -ev


Where ev is given by Equation 4-4, and it is assumed that no horizontal strains

develop as the compactor passes over.

Figure 4-10 shows a comparison of the strains vs. number of passes in the top 6-

inch lift of Section 1. Evident the strains increased by 6% in first pass and then to 9% by

the 4th pass. Using the strains, initial dry density and Eq. 4-5, the computed dry density vs.

pass is shown on the left axis. The computed dry density from the nuclear moisture and

density device is given in Table 4-1, as well as depicted in Figure 4-10. Note the moisture










and densities were measured at 3 locations within the section, and LVDT occurred at one

location. As expected, the measured density variability of the first pass, 3.5 pcf (126.6

pcf-123.1 pcf), is quite high and if added to the mean (124.8 pcf), covers the density

measured by the LVDT (127 pcf), which is at one point.


21

18
15

12


a

3

0
-3


0 1 2 3 4 5
S of Two-Way Passes
Figure 4-10. Strain from LVDT vs. Dry density from NDP for Section 1

Table 4-1. Measured Dry Densities from Nuclear Device within Section 1
Pass # Depth 1 2 3 Average Standard Deviation
0 0-6 120.50 115.20 118.90 118.20 2.72
1 0-6 123.10 126.60 124.80 124.83 1.75
3 0-6 128.80 128.40 N/A 128.60 0.28
4 0-6 129.60 130.20 130.10 129.97 0.32


Figure 4-11 shows the strains in the bottom third and middle third (Figure 3-6) of

Section 2 as a function of passes. Evident from the Figure, the strains within the bottom

and middle third of the thick (12-inch) lift are quite similar from the pad-foot compactor,

suggesting uniform compaction.

Table 4-2 shows nuclear density measurements at 3 locations within Section 2 for


2nd 6 inches Lit over ist 6 inches









passes 0, 4, and 9. Note, in order to measure density, the surface of the section had to be

graded and rolled with the vibratory smooth steel compactor (4th and 6th passes). The

table presents the measured values at 6 inches (i.e., 0-6-inch), 12 inches (i.e., 0-12-inch),

as well as the computed value from 6-12-inch based on Eq. 4-2. As expected, the highest

standard deviation occurred within the 6-12-inch zone; however, the variability

decreased with pass, which is good. A comparison between densities measured or

computed from the Troxler nuclear device or strain LVDT sensors were quite favorable.

Figure 4.12 shows the measured strains in the bottom and middle third (Figure 3-7)

of Section 3 as a function of compactor pass. Figure 4.12 shows the strains in Section 3

are highest for all sections (max. 20%) due to the dynamic force o f compactor, 85,000

lbf. Also evident, the strains within the bottom and middle third of the thick (12-inch) lift

are very similar, suggesting uniform compaction.

Given in Table 4-3 are nuclear density measurements at 3 locations within the

section for passes 0, and 9. No other densities were collected due to time constraints (end

of day, darkness). Evident from the table, the densities of Section 3 at the end of

compaction were the highest and they agreed with the back computed values from the

LVDT instrumentation, Figure 4-12.

4.4 Measured Dry Densities and Moistures vs. FDOT Specified Values

As identified in section 3.1, Modified Proctor (AASHTO T-180) laboratory

compaction tests were performed on the SR826 base materials. An optimum dry density

of 131 pcf and moisture content of 9% was found. FDOT specification 200 requires a

measured field compaction of 98% of T-180 or a dry density of 128.38 pcf Figure 4-13

shows measured field dry densities from the nuclear density probe (NDP) for the last

passes of lifts 1 and 2 of Section 1. Figure 4-13 also shows the moisture contents










measured from the NDP (nuclear density probe) as well as oven samples recovered from

the field. Apparently the back scatter surface moisture measurement is acceptable

measurements over the depth of the deposit.


16

14

12

10
8

6 ,-
4 55

2

0

-2

-4


0 1 2 3 4 5 6 7 8 9 10
S of Two-Way Passes
Figure 4.11 Strain from LVDT vs. Dry density from NDP for Section 2

Table 4-2. Measured and Computed Dr Densities from Nuclear Device within Section 2
Pass # Depth 1 2 3 Average Standard Deviation
0-6 117 116 116 116.33 0.58
0 0-12 116.1 117.3 114.4 115.93 1.46
6-12 115.2 118.6 112.8 115.53 2.91
0-6 126.9 128.3 122.6 125.93 2.97
4 0-12 126.8 129.8 125 127.20 2.42
6-12 126.7 131.3 127.4 128.47 2.48
0-6 134.3 135 133.8 134.37 0.60
9 0-12 134.5 133.2 132.3 133.33 1.11
6-12 134.7 131.4 130.8 132.3 2.1

Figure 4-13 shows the dry density measurements in the first lift (129 pcf) increased

significantly during the compaction of the overlying second lift (133.5 pcf). The latter

may be attributed to the large compactor energy (Figure 4-5) measured in the bottom of


STRAIN CURVE FROM LVDT DATA : MIDDLE




0-6 Avera e
0- I012 Average
6- 12 Ave




STRAIN CURVE FROM LVDT DATA : BOTTOM
I
r.











150

145

140

135

130

125

120

1151

110


STRAIN CURVE FROM LVDT DATA: MIDDLE

-~~~~~ ?*jS **~J









0-12 Aytwga~
R-12 AvenWg
0-GcValueRaw r
0-12 Value Rwg *
6-12 Vauelie Pw6


24

20

16

12
,i
8

4

0

-4


0 1 2 3 4 5 6 7 8 9 10
# of Two-Way Passes

Figure 4-12 train from LVDT vs. Dry density from NDP for Section 3

Table 4-3. Measured and Computed Dry Densities from Nuclear Device within Section 3
Standard
Pass # Depth 1 2 3 Average .ea
Deviation

0-6 117 116 116 116.33 0.47

0 0-12 116.1 117.3 114.4 115.93 1.19

6-12 115.2 118.6 112.8 115.53 2.38

0-6 135.5 139.3 137.40 1.90

9 0-12 141 137 139.00 2.00

6-12 146.5 134.7 140.60 --


first lift during compaction of 2nd lift. Both lifts are well above FDOT Specification 200

or 98% of the modified Proctor or a dry density of 128.38 pcf.

Figure 4-14 shows measured dry densities and moisture contents for the 9th

compactor pass on Section 2. Evident are similarities of densities for both 0-6-inch and

0-12-inch zones for all 10 locations within Section 2. Also note the similarities of

moisture obtained from both the oven samples and NDP (nuclear density probe).











Evident is that the measured densities are well above the required FDOT specification

value of 128.38 pcf


#--NDP-Dry Density-1st lift NDP-Dry Density-1st+2nd lift-0-6
-I--NDP-Dry Density-lst+2nd lift-0-12 a- NDP-Water Content-lst lift
NDP-Water Content-lst+2nd lift-0-6 I- NDP-Water Content-lst+2nd lift-0-12
Oven Wc:lst+2nd lift:0-Ginch 0Oven Wc:Ist+2nd lift:6-12inch
142 40

140
35
138
30
136
25
a 134 --25


.2r^LJJsny-iaS1 p - - - -
132 20 0

S130- 15

128 98% of Dry Density_max=128.38pcf
Optimum Water Content=9% 10
126


12 --------------------------------
124 5

122 0
0 1 2 3 4 5 6 7 8 9 10
Location I
Figure 4-13. Dry densities and Moisture Contents in Section 1

Figure 4-15 shows measured dry densities and moistures in Section 3 for the 9th

pass of the BW 225BV-3 compactor. This section had the highest measured densities, as

well as variability along the section. However, the densities were well above FDOT's

Specification 200 of 128.3 pcf

4.5 Base Stiffness

As identified in section 2.2, the stiffness, and strength of compacted materials are a

function of moisture content and compactive effort (energy). Since, future roadway base

construction will be based on compacted stiffness, AASHTO (2002), the stiffness of two

conventional 6-inch lifts versus the 12-inch thick lift are of great interest. For the stiffness











measurements, Falling Weight Deflectometer (FWD), Soil Stiffness Gage (SSG), as well

as the Evib from the Bomag Varicontrol measurements on the drum (BW 225BV-3) were

measured and compared. FWD and SSG were measured after compaction while Evib from

the Bomag variocontrol was measured during compaction.

Figure 4-16 shows stiffness (Kips/in) measured from the FWD for both lifts of

Section 1, as well as the thick lift Sections 2 and 3 at 10 separate locations. Table 4-4

shows the mean and standard deviation for all ten locations in each section.


NDP-Dry Densty-0-6 ----NDP-Dry Densty-0~12 NDP-Water Content-0-6
-NDP-Water Content-0~12 Oven-Wc:0~6 +-*-Oven-Wc:6~12

142 40

140 35

138
30
136

a 134

132 20 -

1 ry Drensity max=131pcf 7 7 7 7 7
130 15
15 r
98% of Dr Dens itymax=12B.38pct ---------
128
Optimum Water Content=9% 10
126 .

124~~~ ~~~ ---------------U-------------------~
124

122 0
0 1 2 3 4 5 6 7 8 9 10
Location I

Figure 4-14. Dry Densities and Moisture Contents in Section 2

As expected, the stiffness of the first lift of Section 1 increased with the placement

of the second lift due to the compactive effort (energies) improving the underlying layer

(Figure 4-5) densities as shown in Figure 4-13. Interestingly, the FWD stiffness of

Section 2 had the highest mean for all the tested sites as well as the lowest coefficient of










variation (i.e., standard deviation divided by mean). However, Section 3, which had the

highest compactive effort, and used the variocontrol Compactor, had the lowest FWD

mean stiffness, as well as the worse variability. Note however, the FWD employs a larger

loading surface (i.e., 18-inch diameter plate), which has a deeper zone of influence than

the variocontrol compactor drum.


NDP-Dry Densty-0-6 ---NDP-Dry Densty-0~12 NDP-Water Content-0-6
*- NDP-Water Content-0-12 Oven-Wc-O-6 --Oven-Wc-6-12

142 40

140 35

138

136 o d
.....25
S134



S130
0 98% of Dry Density_max=128.38pcf
128
Optimum Water Content=9% 10
1 ..................... .. ..... ... ........ ..........
126

124 5

122 0
0 1 2 3 4 5 6 7 8 9 10
Location I
Figure 4-15. Dry Densities and Moisture Contents in Section 3

Figure 4-17 shows the surface stiffness as measured by the soil stiffness Gage

(SSG) from Humbolt device for each of the ten locations within the 3 Sections. Again,

Section 1 had SSG performed at the end of both the first and second 6-inch lift placement.

Table 4-5 shows mean and standard deviation of the SSG data. Interestingly, the mean

stiffness for the first 6-inch was higher than the measured mean after compaction of the

second 6-inch lift for Section 1. This quite different than the FWD results, Table 4-4,












500
9 sec 1-6-12 O sec 1-0-6 O sec2-0~12 0 sec3-0~12
450

400 --

-350 ---

300

250-

0200
L-
150

100

50


1 2 3 4 5 6 7 8 9 10
location#
Figure 4-16. Stiffness Measured with FWD in All Sections

Table 4-4. FWD Mean and Standard Deviation on Each Section
Section Average Standard Deviation
0~6inch 297 28.32
6-12inch 311 29.78
0~12inch 304 29.15
Section -------
0~12inch 362 34.05
Section ---- ---
0~12inch 303 81.76

suggesting the SSG is measuring a surface phenomenon, whereas, FWD is measuring a

depth phenomenon. Again Section 2, 12-inch lift with the pad foot compactor, had the

highest stiffness, whereas Section 3 was in between section 1 (2nd lift) and Section 2 on

average, but had the worst variability (standard deviation 3.98).

Also of interest is a comparison of stiffness and moduli, Evib, as measured with the

FWD, SSG, and the variocontrol unit for Section 3. It is envisioned that Intelligent









compaction Devices (i.e., varicontrol, etc.), which continuously monitor stiffness or

moduli, will replace nuclear density for quality assessment and control in compaction.

Figure 4-18 shows FWD and SSG stiffness (dashed lines read on left axis), versus

the Evib measurements (read on the right side) as reported by the variocontrol unit as a

function of location. Note the varicontrol Unit was operated in automatic (A, i.e., preset

Evib), and manual (R, i.e., preset amplitude and frequency) modes. Interestingly, after the

first pass, all subsequent passes of the variocontrol unit, had smaller Evib. Moreover, the

variability of the Evib values over the site (i.e., 1-10) is much greater than the initial

values (i.e., pass 1) or FWD data. All of the latter suggest that the unit was possibly

crushing the surface material in site 3. For instance, particle crushing would result in

larger surface deformations or a lower stiffness, k (Eq. 2-2), and a lower Evib (Eq. 2-3)

with subsequent pass.

To further verify the particle crushing theory, the stiffness as a function of depth was

found from the stress gages and accelerometers located 6-inch, 9-inch and 13-inch below

the surface, Figure 3-6. The stiffness was assessed for the loading phase (e.g., Figure 4-8)

and was compared to the Evib, in Figure 4-19. Figure 4-19 shows the stiffness 6-inch or

below increased or remained constant for all passes as compared the surface Evib

measurements (x axis- decreased). The sensor 6-inch below the surface reached its

maximum on the 4th pass, whereas, the bottom (13-inch) reached maximum at the 6th

pass. The increasing stiffness values below 6-inch, supported by the higher densities in

Figure 4-15, are in conflict with the decreasing Evib values with pass number. Further

confirmation of the influence of compactive effort (energies), Figure 4-8, are presented in

section 4.6, concerning strength vs. depth.











25

a sec 1-6-12 O sec 1-0-6 sec2-O-12 sec3-0-


f^, -
20




z 15




10




5




0
1 2 3 4 5 6 7 8
Location I
Figure 4-17. Stiffness measured by SSG in All Sections

Table 4-5. SSG Mean and Standard Deviation on Each Section


9 10


Section Average Standard Deviation
0~6inch 14 2.33
6-12inch 12 1.64
0~12inch 13 2.14
Section --
0~12inch 15 3.50
Section -- -
0~12inch 13 3.98


4.6 Base Strength vs. Depth

Besides stiffness, the strength of base materials beneath the roadway is extremely

important. The latter controls maximum contact pressures (e.g., semi-truck tire

pressures) that the roadway may be exposed without undergoing a bearing failure. One

means of assessing strength in the field is with a static or dynamic cone penetration test.










For this study, an Automatic Dynamic Cone Penetrometer (ADCP) device owned and

operated by the State Materials Office (SMO) in Gainesville was used. SMO

recommended the automatic dynamic cone over the static due to its prior success on other

base project studies.

FWD SSG
Dynamic Stiffness vs. Location# SO 14,42 3.98


-- .FWD -H-SSG :
Vario 1F(M) Vario 4R(A) "
90 -I-Vario GR(M) + Vario GR(A) 140
80
80 120

S70
z 100
2 o / 0

1 50 0- -- 80
50

40 -

E 30
40 E
020



o o
1 2 3 4 5 G 7 8 9 10
Location S

Figure 4-18. Stiffness from FWD & SSG vs. Dynamic Modulus from Vario-System

Figure 4-20 shows the mean and maximum range of ADCP values as a function of

depth for Section 1 after the placement of the second 6-inch lift. Appendix G presents the

data for all ten locations (Figure 3-5), and Table 4-6 reports the mean and standard

deviation of the ten values at depths of 6-inch, 10-inch and 12-inch below the base

surface. Of interest is the number of blows required to achieve a specific depth,

discontinuities (i.e., jumps due to impenetrable rocks schist), as well as the slope

(blows/distance) over a given layer. Figure 4-20 shows Section 1 after compaction was










very uniform with blow count/layer (strength) being similar for each 6-inch lift as well as

the subgrade (zone below the base).


Evib vs. Dynamic stiffness



60 a 13inch below from Surface

i9 Sinch below from surface
a Ginch below from surface

S40--------------------------------



S30 --------------------------- ------- -------




10 ------- -- + -------
10 +++
I .... o . ***. .. ***.




1F(M): E=80 (MN/M^2) 4R(A): E=30 (MN/M^2) 8R(M): E=35 (MN/M^2) FR(A): E=30 (MN/M^2)
Evib vaule for Specific Pass
Figure 4-19. Stiffness and Evib Moduli as Function of Depth and Number of Passes

Figure 4-21 and Table 4-7 shows the mean, range, and variability of ADCP data for

Section 2. Table 4-8 and Figure 4-22 shows the mean, range and variability of ADCP

data for Section 3.

A comparison of mean ADCP data between Section 1 and 2 is given in Figure 4-23.

Evident the mean for both sections are quite similar. However, the mean ADCP data for

Section 3 is significantly higher than Section 1, by a factor of 2. The latter suggests that

the significant energies (Figure 4-8) from BW 225BV-3 resulted in particle crushing of

the surface (Figure 4-18), but higher strength (Figure 4-22) and stiffness (Figure 4-19) in

the underlying materials due to larger contact area and dynamic drum forces in Section 3.



















10



15



20


0 20 40 60 80 100 120 140 160 180


Figure 4-20


Number of Blows
ADCP Data for Section 1 After 2nd Layer


Table 4-6. Summary ADCP Results for Section 1
Depth Average Blow Standard Deviation
6 24 5.34
10 51 8.1
12 64 7.71

Table 4-7. Summary of ADCP Results for Section 2
Depth Average Blow Standard Deviation
6 29 6.69
10 50 9.27
12 59 10.49

Table 4-8. Summary of ADCP Results for Section 3
Depth Average Blow Standard Deviation
6 49 12.27
10 80 12
12 94 9.5






































0 20 40 60 80 100 120 140 160 180 200


Number of Blows
Figure 4-21. ACDP Data for Section 2


-- Lower Bound-- Upper Bound Average



















0 50 100 150 200 250 300 350 401


Number of Blows
Figure 4-22. ACDP Data for Section 3













0



5



10



e-
15



20



25



30


Figure 4-24.


40 60 80 100
Number of Blows

Comparison ADCP Data from Section 1 and 3


Sectionl-full lift Section2


0 20 40 60 80 100 120 140 160 180
Number of Blows
Figure 4-23. Comparison ADCP Data from Section 1 and 2













CHAPTER 5
SUMMARY, CONCLUSION AND CONCLUSION

5.1 Summary

Current practice in Florida for the construction of 12-inch limerock bases for

roadways is to compact two 6-inch layers on top of one another. The latter is generally

accomplished with single or dual drum vibratory steel wheel rollers with dynamic forces

in the 30,000 to 50,000 lbf range. In addition, FDOT Construction Specification 200

stipulates that limerock must be compacted to 98% of the maximum dry density as

obtained in a laboratory Modified Proctor (AASHTO T-180) test.

To accelerate roadway construction, and reduce costs, contractors and compactor

manufacturers have suggested placement of a single 12-inch base lift instead of two 6-

inch layers. For instance the time required for quality control testing, grading, trucking,

scheduling, and delivering a single 12-inch layer instead of two 6-inch lifts might be

substantially reduced. In addition, compactor manufacturers have developed intelligent

and heavier compactors that are capable of varying the energy delivered to the base, as

well as monitoring the stiffness of the compacted material.

To investigate the possibility of compacting 12-inch thick lifts, three tests were

conducted. Table 5-1 describes the condition of each test section. One test section had

two conventional 6-inch lifts, and other two test sections were 12-inch thick lifts

employing different compaction equipment (i.e., pad foot vs. smooth wheel, Table 5-1).

The Miami site was selected due to its subgrade stiffness (i.e., LBR>100), as well

as properties of its placed limerock: well graded, and low fine content with moisture









contents from the mine less than optimum (i.e., 4% -7% as dry part of 9% as optimum

water content). As identified in the literature and lab (Chapter 2), compacting dry of

optimum results in greater stiffness and strength.

Table 5-1. Test Sections and Compactors
Dynamic .
Dynamic Compactor Applied Lift
Location Compactor Force D il i
Detail Thickness
(lbf)

Vibratory Steel
BOMAG Vibratory Steel Conventional lifts
Section 1 BW 21D-3 53,000 Smooth Roller
BW 211D-3 (e.g., two 6-inch)
used conventionally

BOMAG Vibratory Padfoot
Section 2 BOMAG 62,000ro 12-inch thick lift
BW 213PD-3 Roller

BOMAG Vibratory Smooth
Section 3 BOMAG 85,000it 12-inch thick lift
BW 225BV-3 Wheel- ICC Unit


To identify stresses, deformations, and energies within the 6-inch and 12-inch lifts,

stress gages, accelerometers, and LVDT deformation sensors were placed in the top,

middle and bottom third of each placed layer. After compaction of each lift, Falling

Weight Deflectometer (FWD), Soil Stiffness Gage (SSG), and Automatic Dynamic Cone

Penetrometer (ADCP) testing were performed at 10 locations within each site with Ifoot

interval. Of interest were the densities, stiffness, and strengths of material as a function

of depth for the two 6-inch vs. 12-inch thick lifts. Also of importance was the Moduli,

Evib, from Bomag's Intelligent Compaction Control (ICC) unit vs. field measured

stiffness. As expected, the two 6-inch lifts, Section 1, reached 98% of maximum dry

densities within 3 to 5 passes of the conventional smooth steel vibratory compactor.

Strains within the lifts were 6 to 9% with appreciable increase in density occurring within

the lower lift as the upper lift was compacted.

Compaction of Section 2, a 12-inch thick lift, occurred with alternating passes of BW









213PD-3 (5 passes) (i.e., a vibratory a pad foot roller), and a BW 211D-3 (i.e.,vibratory

smooth wheel roller) to smooth the base surface in order obtain accurate moisture and

density measurements. From the field instrumentation, the strains and back computed

densities (Troxler Nuclear Device) in the bottom and the middle of the Section 2 were

quite similar. In addition, the energies and stiffness throughout the depth compared quite

favorably. Surface stiffness measured with either FWD or SSG were similar or slightly

higher with the thick lift, 12-inch section vs. the conventional Section 1. Strength

measured by ADCP and its associated coefficient of variability were quite similar for

both Section 1 and Section 2.

Section 3 was a 12-inch thick lift base compacted with the smooth wheel BW

225BV-3 varioconrol compactor, which can continuously monitor surface stiffness and

varies energies based on moduli, Evib. The compactor had the greatest dynamic force,

85,000 lbf, of any of the tested units. The measured strains with depth were quite uniform

with depth and the highest of all the test sections, 20%. Similarly, the strength measured

with depth by the ADCP was also the highest of all the test sections (i.e., factor of 2).

Unfortunately, even though the variocontrol unit was run in both the automatic and the

manual mode, the surface stiffness or moduli, Evib, decreased with pass number and was

quite variable over the section. The variability attributed to particle crushing of the

surface particles, since the measured stiffness, and strength, increased in depth with pass

based on buried instrumentation and ADCP results.

5.2 Conclusion

From the study, it was conclude that thick lift, 12-inch, compaction of limestone

base courses was achievable under the following conditions:

* Subgrade material of sufficient strength and stiffness (i.e., LBR value over 100).









* The compaction process should be conducted with moisture contents on dry part of
optimum (i.e., 5-8% vs. 9% optimum moisture content).

* Vibratory padfoot roller with at least 60,000 lbf of dynamic force or vibratory
heavy steel smooth roller above 85,000 lbf dynamic force.

5.3 Recommendation

With the successful compaction of thick lift limestone base course in south Florida,

the question of its use in central and north Florida remains. Miami was selected due to

its potential for success (i.e., well graded limerock, low fine content, and moisture

content dry of optimum, as well as stiff subgrade, LBR greater than 100). The next

potential test scenario should be:

* Subgrade stiffness (LBR>100) (i.e., lift placed on stiff limerock subgrade)

* Vibratory pad-foot roller with at least 60,000 lbf of dynamic force or vibratory
heavy steel smooth roller above 85,000 lbf dynamic force

* Limerock material with higher fine content and moisture content wet of optimum,
as typically found in Central Florida.

Also, the stiffness (FWD and SSG) and strengths (ADCP) devices should be the

minimum instrumentation used in the future study.















APPENDIX A
SIEVE ANALYSIS RESULTS


Table A-1. Sample # vs. Location #
Sample # Location#
S-1 1
S-2 1
Section 1 S-3 7
S-4 7
S-5 9
S-6 9
Sample # Station
S-7 2
S-8 2
Section 2 S-9 5
S-10 5
S-11 9
S-12 9
Sample # Station
S-13 3
S-14 3
Section 3 S-15 6
S-16 6
S-17 8
S-18 8























10.00


1.00
DIAMETER (mm)


Figure A-1. Sieve Analysis for S1 and S2


100.00


0.10


0.01


IffiJIIS-1
=S-2 =














100


90


80


70


60


50


40


30


20


10


0
100.00


10.00 1.00 0.10
DIAMETER (mm)
Figure A-2. Sieve Analysis for S3 and S4


0.01














100 -

90- -

80 -

70

60

z
z 50

40

30 -S-5

20 -W-S-6

10

0
100.00 10.00 1.00 0.10 0.01
DIAMETER (mm)
Figure A-3. Sieve Analysis for S5 and S6












100

90

80

70

60

50

40

30

20

10

0
10(


1.00
DIAMETER (mm)
Figure A-4. Sieve Analysis for S7 and S8


0.00


10.00


0.10


0.01


Ilk,




-N-\-\



S-7

lS-8 s,













100

90 ---

80 -

70

60


a:
s 50

40

30 4- .9-S-9

20 -- '-41-S-10 --
20

10-- "

0

100.00 10.00 1.00 0.10 0.01
DIAMETER (mm)
Figure A-5. Sieve Analysis for S9 and S10














100

90

80 --

70

60 -







30
-s-11 -C-s-12
20

10

0 E___ ______
100.00 10.00 1.00 0.10 0.01
DIAMETER (mm)
Figure A-6. Sieve Analysis for S11 and S12














100


90


80


70

60


50--

40


30


20


10


0
100.00


10.00 DIAMP RR (mm) 0.10

Figure A-7. Sieve Analysis for S13 and S14


0.01














100


90


80 -


70


60




S40

30
30 ----------



20 -------
20




10
0 - - --- --
100.00 10.00 1.00 0.10 0.01
DIAMETER (mm)
Figure A-8. Sieve Analysis for S15 and S16














100

90 --

80 -

70

60


," 50
z

40

30
--S-17 "
20 -
o .-S-18 ..
10

0
100.0 10.0 1.0 0.1 0.0
DIAMETER (mm)
Figure A-9. Sieve Analysis for S17 and S18















APPENDIX B
MOISTURE CONTENT MEASURED BY NUCLEAR DENSITY PROBE












Table B-1. Data from Nuclear Density Measurement for Section 1


Density & Water Content from Nuclear Density Measurment for Section 1


After Second lift installed (12 inch)
Subgrade After First lift installed (G inch)
station Two Layer Test Before After 1 Pass After 3 Pass After 4 Pass
Station e
Section (control) Compaction
6 inch 12 inch Pass $2 Pass 13 (Ginch) inchinch 1 nch 6 inch 12 inch 6 inch 12 inch
10 228+00 126.7 129.8
8.5 227+75 133.8 136,6 126,8 129,2 132.4 136.3 137,5 137 142,4
6.5 Wet Density 227+50 127.1 131.8 134.5 133,9 122 134,4 136.6 135.9 138 137,4 139.7
3 227+25 134.7 138,5 126,3 133,1 139.9 138,2 141,7
1 227+00 129.1 136 134.1 136,9
10 228+00 3.5 3,7
8.5 227+75 4,7 5.7 5.3 5 5,4 5,8 5,5 5,7 5.2
6.5 Water Content 227+50 3.4 3,6 4,9 4.4 5.9 6.1 5,3 5,8 5,5 5,6 5,5
3 227+25 5,7 5,9 6.2 6,8 5,4 6,2 5,9
1 227+00 5.9 5,4 5,5 5,9
10 228+00 122.4 125.1
8.5 227+75 127.8 129,2 120,5 123,1 125.7 128.8 130,3 129,6 135,3
6.5 Dry Density 227+50 122.8 127.3 128.2 128,2 115,2 126,6 129.7 128.4 131,1 130,2 132,4
3 227+25 127.4 130,8 118,9 124,8 132.7 130,1 133,8
1 227+00 121.9 129 127.1 129,3















Table B-2. Data from Nuclear Density Measurement for Section 2


Density & Water Content from Nuclear Density Measurment for Section 2


Thick Lif T /ad Subgrade After During Compaction
Thick Lit Test w/Pad SSubgrade (Initial) Compacting with After installed (loose)
Station t Foot Rooler Spreading Water After 4 Pass After 9 Pass
Section 2
6 inch 12 inch 6 inch 12 inch inch 12inch 6 inch 12 inch 6 inch 12 inch
10 228+00 123,1 131,6 133.6 136.3
8.5 227+75 123,1 122,5 133,2 133,8 143,3 143,1
Wet
6.5 ns 227+50 130,3 134 123.9 125.5 136 137,9 142 140,7
Density
3 227+25 115.4 113.3 131,8 134,5 143,5 142,8
1 227+00 132.4 136.8 123.1 124.7
10 228+00 3,4 3,5 4,7 4,4
8.5 227+75 5,2 5.5 4.9 5.5 6.7 6,4
Water
6.5 t 227+50 3,1 3,9 6,8 7,1 6 6,2 5,1 5,6
Content
3 227+25 6,8 7.5 7.5 7.6 7.2 8
1 227+00 4,8 4,9 6,2 5.5
10 228+00 119 127,1 127.6 130.6
8.5 227+75 117 116.1 126,9 126,8 134,3 134,5
6.5 Dry Density 227+50 12G.3 128.9 116 117.3 128,3 129,8 135 133,2
3 227+25 108 105.3 122,. 125 133,8 132,3
1 227+00 126.3 130.4 116 114.4
















Table B-3. Data from Nuclear Density Measurement for Section 3

Density & Water Content from Nuclear Density Measurment for Section 3


Station I Thick Lift Test w/225D Subgrade (Initial) After Compaction
Station # Thick Lift Test w/225D
6 inch 12 inch 6 inch 12 inch
10 227+00
7 226+65 142.3 147.6
Wet
6.5 226+50 134.4 139.7 147.6 146.6
Density
3 226+25 145.5 141.9
1 226+00 134.8 131.5
10 227+00
7 226+65 5.1 4.6
Water
6.5 te 226+50 3.3 2.8 5.9 7
Content
3 226+25 8.8 8.8
1 226+00 3.4 3.4
10 227+00
7 226+65 135.5 141
6.5 Dry Density 226+50 130 135.8 139.3 137.1
3 226+25 133.7 130.5
1 226+00 130.3 127.1















APPENDIX C
OVEN MOISTURE CONTENT RESULTS

Table C-1. Data from Oven Moisture Measurement
SR 826 Oven Moistures
Test Date 11/30/2004
Sample # Sectioni Location % M
1 0" to 6" 1 6.98
2 6" to 12" 1 6.39
3 0" to 6" 7 5.53
4 6" to 12" 7 5.5
5 0" to 6" 9 5.28
6 6" to 12" 9 5.55
Test Date 12/1/2004
Sample # Section 2 Location % M
7 0" to 6" 2 6.88
8 6" to 12" 2 6.79
9 0" to 6" 5 6.7
10 6" to 12" 5 7.5
11 0" to 6" 9 6.62
12 6" to 12" 9 7.78
Test Date 12/1/2004
Sample # Section 3 Location % M
13 0" to 6" 3 7.34
14 6" to 12" 3 6.84
15 0" to 6" 6 7.22
16 6" to 12" 6 7.77
17 0" to 6" 8 6.08
18 6" to 12" 8 6.1














APPENDIX D
DATA REDUCING

D.1 Calculation for Reducing Data

D.1.1 Stress


Reducing Data = (Raw Data-Initial Value)* 100
(Initial Value is the average value of values measured during last 0.4 sec in whole
measuring time, 10 sec)

D.1.2 Strain


Reducing Data= (Raw Data-Initial Value)*Factor
(Initial Value is measured before test)

Table D-1. Factor for Reducing of Strain Data
Section 1 Section 2 Section 3
CH 6 (Bottom 1/ 0.4072 0.3966 0.4054
3)


0.3990


L


CH 7 (Middle 1/3) 0.4058 0.4054
The above factors are calibrated by ARDAMAN & Associates.











D.1.3 Acceleration


Reducing Data= (Raw Data-Initial Value)*Factor*32.17417*12
(Initial Value is the average value of values measured during last 0.4 sec in whole
measuring time, 10 sec)

Table D-2. Factor for Reducing of Acceleration Data
Section 1 Section 2 Section 3
CH 1 (Bottom) 2.5497 2.5484 2.5259
CH 3 (Middle) 2.5484 2.5368 2.5510
CH 5 (Top) 2.5478 2.5336 2.5272
The above factors are calibrated by ARDAMAN & Associates.

D.1.4 Velocity and Displacement from Acceleration Data


V =(A. + Al)/ 2 x (T-T )+V
D, = (_1 + )/2x(7( -7 1)+D,
Where,
A, A, is acceleration of desired time and previous time of one step before desired time.
V, V,1 is velocity of desired time and previous time of one step before desired time.
D, D is displacement of desired time and previous time of one step before desired
time.
T, 7 1 is desired time and previous time of one step before desired time.

D.1.5 Dynamic Stiffness

To make the plot of stress vs. displacement derived from accelerometer for dynamic soil
particle movement, there is the assumption (i.e., the displacement should be occurred
when the compactor is located on above the instrumentation. At that time, the stress
should be peak).

The way to reduce data for dynamic stiffness derived was with matching the
displacement derived from accelerometer with the displacement from LVDT. With
assumption, the velocity derived from accelerometer around peak stress was used for
reducing with trial and error for matching the displacement from between LVDT and
accelerometer.













D.2 Using Worksheet after 3 Passes with Vibratory Padfoot Roller in Section 2

D.2.1 Raw Data

Table D-3. Example of Raw Data
F-DOT Thick Lill TesI wilh 213D-3, Pad-Fool Roller
Tesl Dale r*.: 1 -i:4
Dala -.::, .,: ,lill i i e
File Name c i -:



Raw Data
Local E .:.n.:.i, E.:. h.:.i r 1 I. le r.1'..1 T.:. TII :. I1-E T- 1
ID I/ I1:.? I I l:1T i:i I 1:1- ?:5 :.7I
Initial .:1E -:1 4 : -I:ll -5 .4E -1:i 4 l IE -i:l : :.E-I: 4 I TE-411 1:1 77 1:1 :
Stress Cell Accelero Stress Cell Accelero Stress Cell Accelero LVDT LVDT
TirII- i: H I:II: *i H I:I *: H I: I1 H I:I. i H I:I4 H I:I. H I H I)I

1:1 I i E-I11 4 14E -I: i ;!E-I:14 4 E-i: 1 4 4l E--:1 4 !i: l -4 :iJE-i:I -i -E-I: -1
1:1.4 1 4E-1:1 4 .1 E-)I: -I T.E-1:1: 4 i E-i:l 4 i4E-I1 4 i:EE-0il -4 i iE-i: I -i :EE-i:I
:1. 4E- 51 0 0 4i:E-lil -I T.E-I:1 4 E-I:'I 4 ':E-:' 4 :!.E-lll -4 i:4E-I:i 54JE--:II
I. E-- 5 'i E-I:ll -I 14E-i:41 4 .I E-:41 4 41 E-I:i 4 .I!E-l:- l -4 :! E-i:il .E-l:Il
1.8 2.82E-02 5.01E-01 -8.39E-04 4.32E-01 4.22E-02 4.40E-01 -4.84E-01 -8.53E-01
2 2.95E-02 4.99E-01 -1.14E-03 4.35E-01 4.34E-02 4.399E-01 -4.83E-01 -8.52E-01
:4 : "E-I: 4 3E-01 -I i4E-OT 4 :IE-'I 4 -4nE0: 4 JOE-ii -4 r:E- I -: 5E-01
I. : iiiiE -i-. 4 .i:E -1)I1 -- .E -i1:i 4 :-E -I:11 4 : E -l:I- 4 4IIE -I: 1 -4 i : E --'11 --E --1
.E E-E:- 4 ilE-lI: -I i. :E4. 4 -.E-Il 4 'iIE-I:- 4 4JE-0:1 -4 L E-I:Il -i S.E-01"
;., l 11E -ii 4 ::!E -1)l E -1:I 4 E 4 E -I 4 4 4 E 4 E -41.1 -4 E -,I 1E -1:'
4 1_ :lE- 4 :IE- -I 14E-i:i- 4 L1E- -i 4 ITlE-I-: 4 J:E-i -4 9:E-,- I -: 5-E-1Il
i.4 4 I 1E -I:' 4 .i:!E-l:' -i i :E -i: 44 IE-I:Ii TiE-i:'- 4 Il:IE-Il:l -4 ':i9 E-i:I -i :4E-:ll
3 4 I -I:E-0': 5 ''i E-01 4 4 -4E-',- 4 4JE-1.' i T E-.: 4 4TE-'1 -4 i4E-,' -i 75E-01
S-1--. : IE 1I.I_ 5, 141 -1. I1 I: :iE -i.:i 4 4 E -i:i i IE-1:1 4 4c.E -1I:I -4 EiE -: l -i i 4E -i:1
9995.6 2.82E-02 5.09E-01 -6.64E-03 4.42E-01 3.98E-02 4.41E-01 -4.93E-01 -8.34E-01
9996 2.88E-02 5.13E-01 -6.64E-03 4.38E-01 3.79E-02 4.37E-01 -4.92E-01 -8.34E-01
f... 4 l.E -1:'- 5 151E -Il' -I 47E -1:i 4 .. E --:'l : i E -i: I- 4 : E -I. -:ll -4 '.'E -:'l :4.EE -i:
J I I l E--:1_ 5 14E-I0II -. TE-:i) 4 L E-'iIl i :SE-':1 4 :1E-'ilI -4 '91E-i: l -: :4E-1: I

9997.2 2.94E-02 5.12E-01 -6.64E-03 4.19E-01 3.91E-02 4.22E-01 -4.93E-01 -8.33E-01
9997.6 3.00E-02 5.08E-01 -6.64E-03 4.15E-01 4. 10E-02 4.17E-01 -4.92E-01 -8.34E-01
9998 3.00E-02 5.02E-01 -7.25E-03 4.09E-01 4.05E-02 4.12E-01 -4.92E-01 -8.34E-01
9998.4 2.57E-02 4.98E-01 -1.08E-02 4.05E-01 3.85E-02 4.07E-01 -4.93E-01 -8.30E-01
9998.8 2.82E-02 4.90E-01 -7.25E-03 3.99E-01 3.84E-02 4.03E-01 -4.93E-01 -8.34E-01
S" .1 T E-i:'1 4 iJE-l:'l I:lE--:i : TE-':'I : iE-I:1 IE-i -4 '.4E-i:il -i i4E-i:I
i E : IIIE -ii 4 7. E-II -4 4E -1:I W E -,iI ..E-I i :JE-III -4 :I E -I:I -i :.E -IIl













D.2.2 Reduced Data


Table D-4. Example of Reduced Data
F-DOT Thick Lift Test with 2130-3, Pad-Foot Roller


Test Date
Data
File Name


Dec, 1, 2004
2500/sec during 10 sec
p3-r-c


Reduced Data 1
4198640959 1578.710127 64.68975334 745,1869956 5806741869


2428.602177


Displacement equivalent to Displacement i H '


and Minimum Value for Each Column

durng Compa Reduced Data 2


Stress Cell Accelero
CH02 CH03
psi in/sec2
0,662419339 170175787
0,418273339 2000485
0,418273339 21.79721278
0,479313339 21,19975852
0,509828339 20,60230426
0,479313339 23,58957556
0479313339 21.19975852
0,357243339 20,60230126
0,418273339 20,60230428
0,509828339 18.21248722
0,479313339 16.42012444
-0,008976661 37,38081788
-0,070016661 34,9510008
-0,00876661 34,50046156
-007016661 30,7882102
-0070016661 27,18409516
-0253126661 21,79721278
-01310666 16, I20124411
-0070016661 8,813121725
-0070016661 3.863790613
-0,1]106661 -1,513297899
-0148206661 -5.69517752
-0131016661 -11,08238019
-0,311156661 -13,47217724
-0,070016661 -20, 0441741


Stress Cell
CH04
psi
0,388613686
0,449613686
0,327513686
0,57171368886
0,327513686
0,449613686
0,449613686
0,388613686
0,205413686
0,464913686
0,266513686
-0,160786314
-0,221786314
0,022313686
0,083113686
-0,099686314
0,083113686
-0,038686314
0,02213686
02054113686
0159713686
-0,038686314
-0,053986314
00937613686
-0,099686314


Accelero
CH05
in/sec2
12,17990047
15,18340353
16.80677571
18,59687755
221868632
20,99348198
22,1868632
22,1868632
21.59016259
21.59016259
19,80006075
31,734073
28,75058994
27,10719778
23,38026443
19,19357816
13,82327265
8452967139
1276062852
-0,507321025
-5,280928925
-10 ,05153382
-14,21122009
-18,11812138
-23, 19172928


LVDT LVDT


CH06
inch
-0,578408804
-0,579166878
-0,578285858
-0,579107388
-0,579408804
-0,579188878
-0,579166878
-0,5793843814
-0,579166878
-0,578824852
-0,578924952
-0,58304188
-0,5832893586
-0,582795768
-0,58304166
-0,582795768
-0,582795768
-0,582795768
-0,58304188
-0,582795768
-0,582795768
-0,58304188
-0,58304166
-0,5832893586
-0,58322013


CH07
inch
-0.713094546
-0,713589134
-0,713958048
-0,718843318
-0,71334184
-0,713094548
-0,71334184
-0,71328103
-0,71334184
-0,713094546
-0.713094546
-0,705918988
-0,70616626
-0,705918988
-0,705854102
-0,705854102
-0,705671672
-0,705854102
-0,705424378
-0,705671672
-0,705671672
-0,704183854
-0,705671672
-0,705918966
-0,70616626


Velocity from Accelerometer


CHOIR
in/sec
0
0,0092168888
0,01951407
0,03011459
0,041548923
0,052446312
0,062863552
0,073010717
0,082527177
0,0981053338
0.09834961
3602013542
3,612790894
3,625250735
3,63902951
3,651255619
3,67055862
88686981658
3,70280451
3717126989
,730126905
37107841219
3,719010789
3,751686056
3,757928611


CH03

0

0,007404486
0.015764898
0,0243684293
0,032724705
0,041563081
0,050520948
0,05888136
0.067122282
0,07488524
0,081811763
2,039331699
2,053790063
2,067680355
2,080734211
2,092324795
2,102121056
2,109764524
2,114777234
2,117278677
2,117748775
2116830702
2,112951453
2,108040545
2,101337275


CH05
in/sec
0
0,005480881
0,011862697
0,018943427
0,027100175
0,03573621
0,044372306
0,053247051
0,062002456
0,070638521
0,078916566
8,845916672
8,858013601
8,869185154
8,879282647
8,887797415
8,894400785
8,898856033
8,901401839
8,902155587
8,900997936
8,897930844
8,893071693
8,886539824
8,878217853


Displacement from Accelerometer
CHOIR CH03 CH05
in in n
0 0 0
1.84337E-086 1,80E-06 1,09373E-06
7.58956E-06 6.11477E-06 4.56E-06
1.75747E-05 1.41408E-05 107212E-05
3.19667E-05 2.55584E-05 1,9299E-05
5,07858E-05 ,04186E-05 3824972E-05
7.38278E-05 5.88328E-05 4,5189E-05
0,000101009 8,07132E-05 680428E-05
0,000132122 0,000105914 9,10927E-05
0,000166838 0,000148315 0.000117621
0,000204719 0,000 16555 0,000147532
19,5038722 13,29622328 82,16390309
19,50530]18 13,2970419 82,16744388
19,5078779 13,297882 82,17099832
19,5082105 1,29869588 62.17453901
19,50969931 13,29953019 6217809243
19,51116127 13,3006938 62.18164887
19,51263578 13,30121176 62,18520752
19,514111371 13,30205667 82,18878757
19,51559778 1330290308 62,19232828
19,51708729 130375008 62,19588891
19,51858117 13,30459869 2,1991187
19,52007944 130511275 2,2030069
19,52158018 133082695 62,20656282
1952308271 13,30712882 62.21011577


I.- .
Stress Cell
CHOO
psi
0,48190959
0,23780959
0,23780959
0,25300959
0,11570959
0,25300959
0,06990959
0,2988000959
0,05470959
0,42090959
0,11570959
0,42090959
0,42090959
-0,06731990
0,11570959
0,17670959
0,48190959
0,35980959
0,23780959
0,29880959
0,29880959
-012849041
0,11570959
0,05470959
0,29880959


Accelero
CHOI
in/sec2
21,54170331
241,542863448
S2,94337941
27,54358584
28,14375188
S2834319318
25,74300694
2514282071
22,28947632
20, 34133084
S1614002721
24,54263448
29, 34412434
32,95508086
35,95601203
1015731566
41835768813
40,7575019
38,35675696
31875563956
28,74393811
21,54263448
16,74021344
11,48612412
1726649658


I







































5200 5400 5600 5800 GO00 6200 6400 6600
Time(msec)
Figure D-1. Stress from Stress Cell vs.Time


10 -


O I


-10 -
5000


6800














-0.5
----- Middle --Top



-0.55




-0. 6




CL
00



-0,7




-0.75
4500 5000 5500 6000 6500 7000 7500
Time(msec)
Figure D-2. Displacement from LVDT vs. Time






































5400 5600 5800 6000 6200 6400 6600
Time(msec)


Figure D-3. Acceleration vs. Time


3000

2500

2000

1500

1000

500

0

-500

-1000


-1500

-2000
5000


5200


6800


7000


















APPENDIX E
RESULTS OF SSG

Table E-1. SSG Data for Section 1
1st 6" lift
Subcrade Cover# 2 Cover# 3
STD DEV SSG VALUE STD DEV SSG VALUE STD DEV SSG VALUE
1 7.12 11 46 1 2.37 7.69 1 141 1082
2 2.28 11.04 2 1.44 8.93 2 1.48 10.48
3 1.45 7.90 3 1.40 11.26 3 1.51 12.12
4 2.57 1228 4 1.22 9.83 4 1 49 11 80
5 1.47 10.85 5 1.22 9.59 5 1.73 12.86
6 1.70 11.94 6 2.06 7.95 6 3.12 12.57
7 2.08 1281 7 1.52 1179 7 138 1035
8 1.70 12.68 8 1.59 12.15 8 1.78 13.74
9 2.47 13.46 9 1.83 13.03 9 1.81 13.55
10 1.85 11 53 10 1.48 1469 10 223 1557

2nd 6" lift
Cover# 1 Cover# 3 Cover# 4
STD DEV SSG VALUE STD DEV SSG VALUE STD DEV SSG VALUE
1 1.39 7.32 1 1.59 1321 1 1 58 11 49
2 1.11 7.22 2 1.84 12.61 2 1.34 11.80
3 1.20 9.02 3 1.87 14.46 3 1.86 11.80
4 1.61 1224 4 1.98 1300 4 240 1510
5 1.36 11.20 5 1.62 12.54 5 1.83 14.66
6 1.41 9.26 6 2.27 16.69 6 1.43 11.43
7 1.39 1252 7 2.03 1505 7 231 1756
8 1.25 10.21 8 1.96 14.36 8 1.98 16.97
9 1.19 8.87 9 1.69 13.12 9 1.49 15.76
10 1.52 9.02 10 2.42 1211 10 172 1424















Table E-2. SSG Data for Section 2


Subt rade
STD DEV SSG VALUE
1 174 1383
2 2.36 15.11
3 2.09 16.03
4 219 1595
5 214 1202
6 213 1591
7 202 1291
8 232 1697
9 1 54 11 17
10 191 1415
Note subgrade not done with Padfoot


Note 3 covers wi D


Table E-3. SSG Data for Section 3

Subgrade
STD DEV SSG VALUE

1 666 1799

2 258 1641

3 332 24 13

4 245 1632

5 324 1726

6 232 1413

7 217 1598

8 175 13 18

9 2.09 15.52

10 2.63 14.95


Cover# 9
STD DEV SSG VALUE

1 1.33 9.90

2 1.63 1369

3 1.43 11 08

4 1.29 7.87

5 8.97 1546

6 2.26 1834

7 1.57 7.23

8 2.08 9.50

9 1.84 14.81

10 2.18 17.59


Cover# 4
STD DEV SSG VALUE
1 113 1061
2 1.20 8.18
3 1.42 8.72
4 122 1028
5 1 37 11 62
6 1 59 11 59
7 1 27 11 06
8 1 26 1064
9 253 931
10 1 40 1264


Cover# 9
STD DEV SSG VALUE
1 1 35 1351
2 1.35 12.37
3 1.37 11.59
4 1 66 1164
5 221 18 11
6 190 1653
7 222 1714
8 1 43 1303
9 257 1923
10 293 21 47


II I II I


I I















APPENDIX F
RESULTS OF FWD
















-* 1st 6" Lift A 2nd 6" Lift


1.05

Stations


Figure F-1. DO Impulse Stiffness Modulus for Section 1


500



400
-


300



200



100


OF


1.03


1.09


1.10


Subgrade

















-* 12 Lift


.03 1.04 1.05 1.06 1.07

Stations

Figure F-2. DO Impulse Stiffness Modulus for Section 2


1.08


600
Du

S500


S400
-

300


200


100


1.02


Subgrade



















- 12 Lift


1.05


Stations

Figure F-3. DO Impulse Stiffness Modulus for Section 3


800



S600

CO
0t
Q


1.02


1.03


Subgrade















APPENDIX G
RESULTS OF ADCP
















Table G-1. Slope Summary
SR 826 -Miami Dade -Control Section
DCP Slope Summary (Depth vs. Blows)

Section 1 Sloe (Depth vs. Blows)
(BW 211D) Base st Lift Base 2nd Lift Subgrade
Location 0" -6" 6" 12" 12" 24" 0" -6" 6" 12" 12" -24" 0" 12"
1 0397 0251 0231 0358 0156 0125 0094
2 0357 0165 0148
3 0283 0209 0158 0308 0143 0144 0164
4 0272 0140 0180
5 0324 0354 0273 0206 0128 0208 0327
6 0180 0130 0156
7 0209 0228 0126 0171 0139 0123 0219
8 0237 0113 0131
9 0251 0196 0189 0191 0147 0143 0216
10 0173 0168 0148
Average = 0.293 0.247 0.196 0.245 0.143 0.151 0.204
St. Dev. = 0.072 0.063 0.058 0.074 0.017 0.026 0.086
COY= 0.246 0.255 0.298 0.302 0.120 0.173 0.420


SR 826 Miami Dade Section 2
DCP Slope Summary (Depth vs Blows)
Section 2 Slope (Depth vs. Blows)
(BW 211D) Base- 1st Lift Subgrade
Location 0" -6" 6" -12" 12" -24" 0" -12"
1 0173 0235 0138
2 0198 0192 0152 0099
3 0223 0 243 0115
4 0278 0232 0210 0170
5 0.192 0.230 0.146
6 0.179 0.203 0.107 0.128
7 0.160 0.140 0.183
8 0174 0213 0123 0163
9 0130 0224 0125
10 0121 0169 0135 0279
Average = 0.190 0.213 0.144 0.140
St. Dev. = 0.042 0.032 0.034 0.033
COV= 0.222 0.149 0.233 0.237



SR 826 Miami Dade Section 3
DCP Slope Summary (Depth vs Blows)
Section 3 Slope (Depth vs. Blows)
(BW 225D) Base- 1st Lift Subgrade
Location 0" 6" 6" 12" 12" -24" 0" 12"
1 01397 01409 00546
2 01314 0 1145 00906 0 1285
3 01311 01105 00736
4 0 1709 0 1151 00608 00859
5 0 0708 0677 00883
6 0 1019 0 1132 00716 0 1941
7 01255 01027 00812
8 00856 00598 00408 02811
9 01041 00913 00706
10 0 1009 00967 00973 0 1684
Average = 0.1179 0.1015 0.0702 0.1724
St. Dev. = 0.0304 0.0253 0.0161 0.0550
COV = 0.2582 0.2483 0.2291 0.4932















Table G-2. DCPI Summary
SR 826 Miami Dade -Control Section
DCPI Summary (DCPIvs Depth)

Section 1 Base 1st Lift Base -2nd Lift Sub gade
(BW211D) 0" 6" Limerock 6" -12" Subgrade 0" -6" Limerock 6" 12" Limerock 12" -24" Subgrade 0" -6" Subgrade
Location Average St. Dev. Average St. Dev. Average St. Dev. Average St. Dev. Average St. Dev. Average St. Dev.
1 0414 0153 0326 0060 0365 0082 0169 0042 0151 0034 0218 0218
2 0356 0107 0179 0058 0172 0047
3 0281 0062 0 246 0047 0 297 0077 0149 0024 0159 0061 0 199 0120
4 0 0263 0100 0149 0036 0177 0038
5 0327 0047 0333 0047 0209 0048 0141 0051 0210 0025 0430 0140
6 0196 0051 0139 0038 0155 0036
7 0231 0105 0228 0065 0189 0053 0147 0050 0126 0036 0227 0075
8 0 246 0033 0131 0058 0140 0045
9 0263 0043 0230 0044 0203 0040 0158 0038 0140 0021 0268 0134
10 0185 0039 0172 0055 0153 0040
Average 0.303 0.273 0.231 0.153 0.158 0.268
St. Dev. 0.071 0.052 0.068 0.016 0.024 0.094
COV 0.234 0.192 0.271 0.102 0.150 0.350

SR 826 Miami Dade Section 2
DCI Summary (DCPIvs Depth)

Section 2 Base Sub grade
(BW 211D) 0" 6" Limerock 6" 12" Limerock 12" 24" Subgrade 12" Subgrade
Location Average St. Dev. Average St. Dev. Average St. Dev. Average St. Dev.
1 0180 0025 0237 0024 0160 0057
2 0210 0045 0198 0042 0177 0052 0159 0078
3 0234 0 062 0 241 0 036 0183 0067
4 0296 0105 0229 0068 0206 0041 0218 0040
5 0199 0039 0230 0028 0151 0036
6 0188 0048 0198 0029 0129 0033 0181 0064
7 0168 0052 0141 0032 0206 0042
8 0188 0048 0213 0047 0130 0038 0199 0120
9 0149 0051 0228 0082 0131 0037
10 0132 0053 0166 0040 0138 0034 0329 0209
Average = 0.194 0.208 0.161 0.217
St. Dev. 0.046 0.033 0.030 0.066
COV= 0.237 0.158 0.189 0.305

9R *'' f.i.JId Do&d ...
L : i T.. -. -[ F -j rl ,

Section 3 Base Subgrade
(EW225D) 0" -6" Limerock 6" -12" Limerock 12" -24" Subgrade 12" Subgrade
Location Average St. De. Average St. Dev. Average St. Dev. Average St. Dev.
1 0153 0049 0138 0026 0075 0026
2 0151 0047 0134 0049 0139 0051 0169 0110
3 0136 0037 0111 0 042
4 0178 0045 0134 0041 0088 0033 0128 0077
5 0099 0035 0090 0035
6 0117 0 041 0129 0 044 0103 0030 0 290 0174
7 0139 0046 0106 0026 0138 0041
8 0099 0047 0085 0031 0097 0037 0541 0351
9 0109 0039 0098 0036 0103 0038
10 0106 0042 0116 0044 0106 0033 0189 0116
Average = 0.129 0.114 0.106 0.264
St. Dev. = 0.027 0.019 0.022 0.166
COV 0.209 0.169 0.210 0.631























--- Location 3

Location 4

Location 5
2" 10 "'.
d Location 6

---- Location 7

-* Location 8

-- Location 9

.. Location 10

20





25
0 20 40 60 80 100 120 140 160 180

Number of Blows

Figure G-1. Depth vs. Number of Blows for Section 1






















5 -
-,-M Location 3
SrA Location 4

10 A Location 5
'" 10
%, -o- Location 6
'r Location 7

S-- Location 8

I..- Location 9
20
...,* Location 10






25
0 20 40 60 80 100 120 140 160 180 200

Number of Blows
Figure G-2. Depth vs. Number of Blows for Section 2






















5
Location 3

--A-- Location 4
A, Location 5
" 10
-*-Location 6
-- Location 7
< ---- Location 8
g15

A Location 9

SLocation 10

20





25
0 50 100 150 200 250 300 350 400

Number of Blows

Figure G-3. Depth vs. Number of Blows for Section 3















LIST OF REFERENCES


Forssblad, L., 1965, "Investigations of Soil Compaction by Vibration" Acta Polytechnica
Scandinavia, No. Ci-34, Stockholm.

Forssblad, L.,1977, "Vibratory Compaction in the Construction of Roads, Airfields,
Dams, and Other Projects," Research Report No. 8222, Dynapac, S-171, No. 22,
Solna.

Parsons, A.W., Krawczyk, J. and Cross, J.E., Mar. 1962, "An Investigation of the
performance of an 8.5 ton Vibrating Roller for the Compaction of Soil" Road
Research Laboratory Note. LN/64/ AWP.JK.JEC.

Seed, H.B., and Chan, C.K., 1959, "Structure and Strength Characteristics of
Compacted Clays", Journal of the Soil Mechanics and Foundations Division,
American Society of Civil Engineers, Vol.85, No. SM5, pp.87-128.

Townsend, F.C. & Anderson, B., 2004, "A Compendium of Ground Modification
Techniques," Research Report BC-354, pp. 16-60. Florida Department of
Transportation (FDOT).

Turnbull, W.J., and Foster, C.R., 1956, "Stabilization of Materials by Compaction",
Journal of the Soil Mechanics and Foundations Division, American Society of Civil
Engineers, Vol. 82, No.SM2, pp.934-1-934-23.

Yoo, T.S., 1975, "A Theory for Vibratory Compaction of Soil", Ph.D dissertation
University of New York, Buffalo, NY.















BIOGRAPHICAL SKETCH

Jeongsoo Ko was born in Gwangju, South Korea. He spent his childhood in that

beautiful city where he finished primary, middle, high school, and university, except

during military service. He was accepted to study civil engineering at Chosun Univerity,

Gwangju, South Korea in 1994. He earned the degree of Engineering Bachelor in March

2002. During undergraduate school, he did 26 months of military service at the border

between South and North Korea.

He realized that his knowledge was far from enough to deal with real work problems.

So he decided to go abroad for advanced education. He was accepted by the Civil and

Coastal Engineering Department at the University of Florida and went to the U.S. in Jury

2003. He had studied and worked on thick lift compaction with Dr. McVay for 1 year.

Including this period, I spent the whole 18 months to study his background in

Geotechnical Engineering. He earned his masters's degree in August 2005. He plans to

continue there for his Ph.D.