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Comparison of Laboratory Compacted Plant Mix and Field Cores

Permanent Link: http://ufdc.ufl.edu/UFE0044317/00001

Material Information

Title: Comparison of Laboratory Compacted Plant Mix and Field Cores
Physical Description: 1 online resource (58 p.)
Language: english
Creator: Bekoe, Michael Ankamah
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2012

Subjects

Subjects / Keywords: analysis -- asphalt -- bekoe -- compacted -- compaction -- comparison -- compliance -- cores -- cracking -- creep -- energy -- field -- fracture -- gradation -- gyrations -- indirect -- laboratory -- michael -- mix -- mixture -- modulus -- plant -- project -- rate -- ratio -- resilient -- superpave -- tension -- test
Civil and Coastal Engineering -- Dissertations, Academic -- UF
Genre: Civil Engineering thesis, M.S.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: The effect between laboratory compaction and field compaction has been assessed by many researchers but little has been done to evaluate the compaction effect on the prediction of cracking performance. Plant mix asphalt mixtures were obtained after mixing and compacted in the laboratory under short term aging conditions to reach the compaction temperatures. Field cores were similarly obtained shortly after pavement compaction. Mixture properties of the laboratory compacted specimens for various Superpave projects indicated that compaction in the laboratory generally predicts conservative values for fracture energy and energy ratio. Energy ratio, which is the appropriate parameter for HMA crack performance prediction seems to be the parameter most sensitive to compaction effects, compared to fracture energy and damage rate (creep rate). Mixture properties such as resilient modulus and strength were insensitive to compaction effects.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by Michael Ankamah Bekoe.
Thesis: Thesis (M.S.)--University of Florida, 2012.
Local: Adviser: Roque, Reynaldo.

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2012
System ID: UFE0044317:00001

Permanent Link: http://ufdc.ufl.edu/UFE0044317/00001

Material Information

Title: Comparison of Laboratory Compacted Plant Mix and Field Cores
Physical Description: 1 online resource (58 p.)
Language: english
Creator: Bekoe, Michael Ankamah
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2012

Subjects

Subjects / Keywords: analysis -- asphalt -- bekoe -- compacted -- compaction -- comparison -- compliance -- cores -- cracking -- creep -- energy -- field -- fracture -- gradation -- gyrations -- indirect -- laboratory -- michael -- mix -- mixture -- modulus -- plant -- project -- rate -- ratio -- resilient -- superpave -- tension -- test
Civil and Coastal Engineering -- Dissertations, Academic -- UF
Genre: Civil Engineering thesis, M.S.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: The effect between laboratory compaction and field compaction has been assessed by many researchers but little has been done to evaluate the compaction effect on the prediction of cracking performance. Plant mix asphalt mixtures were obtained after mixing and compacted in the laboratory under short term aging conditions to reach the compaction temperatures. Field cores were similarly obtained shortly after pavement compaction. Mixture properties of the laboratory compacted specimens for various Superpave projects indicated that compaction in the laboratory generally predicts conservative values for fracture energy and energy ratio. Energy ratio, which is the appropriate parameter for HMA crack performance prediction seems to be the parameter most sensitive to compaction effects, compared to fracture energy and damage rate (creep rate). Mixture properties such as resilient modulus and strength were insensitive to compaction effects.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by Michael Ankamah Bekoe.
Thesis: Thesis (M.S.)--University of Florida, 2012.
Local: Adviser: Roque, Reynaldo.

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2012
System ID: UFE0044317:00001


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1 COMPARISON OF LABORATORY COMPACTED PLANT MIX AND FIELD CORES By MICHAEL ANKAMAH BEKOE A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF M ASTER OF SCIENCE UNIVERSITY OF FLORIDA 2012

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2 2012 Michael Ankamah Bekoe

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3 To m y b eloved w ife, Gloria

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4 ACKNOWLEDGMENTS Immense appreciation goes to the chair of my supervisory committee, Dr. Reynaldo Roque, Professor in Civil Engineering for his guidance and support throughout the course of my studies. I would also wish to acknowledge Dr. Mang Tia for his continual support and as a member of my committee. I also want to appreciate the effort of George Lopp for his valuable time and help wi th laboratory experiment s Thanks are also extended to Sanghyun Chun, Dr. Jian Zou Dr Yu Chen for their help in the course of th is study. Finally, a very special acknowledgement goes to my brother, Patrick Bekoe, my wife, Gloria Bekoe for their love, con fidence, encouragement and constant guidance especially in difficult times. I would also extend thanks to all family and friends in Ghana and Gainesville for their unflinching prayers.

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5 TABLE OF CONTENTS page ACKNOWLEDGM ENTS ................................ ................................ ................................ .. 4 LIST OF TABLES ................................ ................................ ................................ ............ 7 LIST OF FIGURES ................................ ................................ ................................ .......... 8 LIST OF ABBREVIATIONS ................................ ................................ ........................... 10 ABSTRACT ................................ ................................ ................................ ................... 11 CHAPTER 1 INTRODUCTION ................................ ................................ ................................ .... 12 1.1 Background ................................ ................................ ................................ ....... 12 1.2 Objectives ................................ ................................ ................................ ......... 13 1.3 Scope ................................ ................................ ................................ ................ 13 1.4 Research Approach ................................ ................................ .......................... 13 2 LITERATURE REVIEW ................................ ................................ .......................... 15 2.1 Background ................................ ................................ ................................ ....... 15 2.2 General Considerations of Compaction and Res earch Findings ...................... 15 2.3 Laboratory Compaction Methods ................................ ................................ ...... 18 2.3.1 Gyratory Compactor ................................ ................................ ................ 18 2.3.2 Vibratory Compactor ................................ ................................ ................ 19 2.3.3 Kneading Compaction ................................ ................................ ............. 20 2.3.4 Impact Compaction ................................ ................................ .................. 20 2.4 Effect of Reheating on Compacted Specimens ................................ ................ 20 2.5 Aging Effect on Asphalt Mixtures ................................ ................................ ...... 21 2.6 Pr ediction of Cracking Performance of Asphalt Mixtures ................................ .. 22 3 TEST PROCEDURE ................................ ................................ ............................... 26 3.1 Sample Preparation and Aging ................................ ................................ ......... 26 3.2 Compaction and Determination of Air Void ................................ ....................... 27 3.3 Cutting ................................ ................................ ................................ .............. 28 3.4 Attaching Gage Poi nts ................................ ................................ ...................... 29 3.5 Indirect Tension Test Procedure ................................ ................................ ....... 29 3.6 Resilient Modulus Test ................................ ................................ ...................... 30 3.7 Creep Compliance Test ................................ ................................ .................... 31 3.8 Strength Test ................................ ................................ ................................ .... 32

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6 4 TEST RESULTS AND ANALYSIS ................................ ................................ .......... 34 4.1 Background ................................ ................................ ................................ ....... 34 4.2 Comparison between Field and Lab Compacted Air Void ................................ 34 4.3 Resilient Modulus ................................ ................................ .............................. 36 4.4 Creep Compliance/Creep Rate ................................ ................................ ......... 38 4.5 Tensile Strength ................................ ................................ ................................ 40 4.6 Fracture Energy ................................ ................................ ................................ 42 4.7 Failure Strain ................................ ................................ ................................ .... 43 4.8 Energy Ratio ................................ ................................ ................................ ..... 45 5 CONCLUSION ................................ ................................ ................................ ........ 47 5.1 Summary of Findings ................................ ................................ ........................ 47 5.2 Issues ................................ ................................ ................................ ............... 47 5.3 Future Research ................................ ................................ ............................... 47 APPENDIX A LABORATORY GRADATION ................................ ................................ ................. 48 B FIELD GRADATION ................................ ................................ ............................... 51 C T TEST DAT A ................................ ................................ ................................ ......... 54 LIST OF REFERENCES ................................ ................................ ............................... 57 BIOGRAPHICAL SKETCH ................................ ................................ ............................ 58

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7 LIST OF TABLES Table page 2 1 Energy based mixture specification criteria ................................ ........................ 25 3 1 Mixture information ................................ ................................ ............................. 26 3 2 Binder information for project sections ................................ ............................... 26 3 3 Comparison of DASR gradation parameters ................................ ...................... 27 3 4 Number of gyrations and % air v oids ................................ ................................ .. 28 4 1 Comparison between field and laboratory mixture properties ............................. 36 A 1 Aggregate gradation for project 8 ................................ ................................ ....... 48 A 2 Aggregate gradation for project 9 ................................ ................................ ....... 48 A 3 Aggregate gradation for project 10 ................................ ................................ ..... 49 A 4 Aggregate gradation for project 11 ................................ ................................ ..... 49 A 5 Aggregate gradation for project 12 ................................ ................................ ..... 50 B 1 Aggregate gradation for project 8 ................................ ................................ ....... 51 B 2 Aggregate gradation for project 9 ................................ ................................ ....... 51 B 3 Aggregate gradation for project 10 ................................ ................................ ..... 52 B 4 Aggregate gradation for project 11 ................................ ................................ ..... 52 B 5 Aggregate gradation for project 12 ................................ ................................ ..... 53 C 1 Project 8 ................................ ................................ ................................ ............. 54 C 2 Project 9 ................................ ................................ ................................ ............. 54 C 3 Project 10 ................................ ................................ ................................ ........... 55 C 4 Project 11 ................................ ................................ ................................ ........... 55 C 5 Project 12 ................................ ................................ ................................ ........... 56

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8 LIST OF FIGURES Figure page 2 1 Distribution of void content in gyratory compacted specimen. ............................ 16 2 2 Schematic diagram of Superpave Gyratory Compactor ................................ ..... 19 2 3 Effect of temperature on air voids measured after compaction using diff erent compaction methods for HMA containing a fine crushed gravel mixture. ........... 21 2 4 Determination of fracture energy ................................ ................................ ........ 25 3 1 Specimen s in cutting machine ................................ ................................ ............ 29 3 2 Specimen in vacuum pump ................................ ................................ ................ 30 3 3 Material Testing System ................................ ................................ ..................... 30 3 4 Creep compliance curve based on power model ................................ ................ 31 3 5 Typical failure mode of IDT test specimens ................................ ........................ 33 4 1 Compar ison between field and laboratory air void ................................ .............. 35 4 2 Correlation between lab and field compacted specimens ................................ ... 35 4 3 Comparison between field and laboratory resilient modulus .............................. 37 4 4 Correlation between field and laboratory specimens ................................ .......... 37 4 5 Comparison between field a nd laboratory creep compliance ............................. 38 4 6 Comparison between field and laboratory creep rate ................................ ......... 39 4 7 Creep rate correlation between fie ld and laboratory specimens ......................... 39 4 8 Creep compliance correlation between field and laboratory specimens ............. 40 4 9 Comparison between F ield and Laboratory Strength ................................ ......... 41 4 10 Strength correlation between lab and field compacted specimens ..................... 41 4 11 Comparison between fie ld and laboratory fracture energy ................................ 42 4 12 Fracture energy correlation ................................ ................................ ................ 43 4 13 Comparison between field and laboratory failure stra in ................................ ...... 44

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9 4 14 Failure strain correlation ................................ ................................ ..................... 44 4 15 Comparison between field and laboratory failure strain ................................ ...... 45 4 16 Energy ratio correlation ................................ ................................ ...................... 46

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10 LIST OF ABBREVIATION S ANOVA Analysis of Variance ARB Asphalt Rubber Binder CP Control Point DASR Dominant Aggregate Size Range DCSE f Dissipated Creep S train Energy to Failure EE Elastic Energy FDOT Florida Department of Transportation G mm Theoretical Maximum Specific Gravity HMA Hot Mix Asphalt IDT Indirect Tension Test ITLT Indirect Tension Test at Low Temperature JMF Joint Mix Formula LCPC Central Labo ratory for Bridges and Roads M R Resilient Modulus MTS Material Testing System NCHRP National Cooperative Highway Research Program PG Performance Grade RZ Restricted Zone SHRP Strategic Highway Research Program SPSS Statistical Package for the Social Scienc es

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11 Abstract of Thesis Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Master of Science COMPARISON OF LABORATORY COMPACTED PLANT MIX AND FIELD CORES By M ichael A nkamah B eko e M ay 2012 Chair: Reynaldo Roque Major: Civil Engineering The effect between laboratory compaction and field compaction has been assessed by many researchers but little has been done to evaluate the effect of compaction on the prediction of cracking pe rformance. Plant mix asphalt mixtures were obtained after mixing and compacted in the laboratory under short term aging conditions to reach the compaction temperatures Field cores were similarly obtained shortly after pavement compact ion Mixture properti es of the laboratory compacted specimens for various Superpave projects indicated that compaction in the laboratory generally predicts conservative values for fracture energy and energy ratio. Energy ratio which is the appropriate parameter for HMA crack performance prediction seems to be the parameter most sensitive to compaction effects, compared to fracture energy and damage rate (creep rate) M ixture properties such as resilient modulus and strength were insensitive to compaction effects.

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12 CHAPTER 1 I NTRODUCTION 1.1 Background The strategic Highway research program (SHRP) was initiated with the aim of system. Superpave was the principal term of the asphalt research p ro duct under this program and it consisted of three main sections; (1) an asphalt binder specification, (2) an HMA mix design method (3) HMA tests and performance prediction models. Since its implementation by the Florida Department of Transportation (FDOT), it became imperative to monitor the performance and material characteristic s of Superpave project sections in order to establish a database upon which the design procedures and models could be updated. The performance characteristics of asphalt specimens in the field are influenced by its characteristics in the laboratory. S tudies related to the effect of laboratory compaction on field performance abounds. Some have looked at the effect of compaction mode on the mechanical performance and variability of as phalt mixtures. Superpave recommends the use of the Superpave G yratory compactor as the best mode to simulate the density of the Hot Mix Asphalt (HMA) obtained in the field under certain traffic conditions Significant among them is the evaluation of the r elationship between field compaction method and laboratory compaction method with respect to their effect on rutting performance. Very little, if any of such relationship between laboratory compacted specimen and field compacted specimens based on their cr acking performance has been evaluated. This study focusses on characterizing the cracking behavior of laboratory compacted plant mix asphalt in comparison with field compacted asphalt using the HMA fracture mechanics approach developed at the

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13 University of Florida To evaluate this u n aged core s Superpave project sections were taken along with samples of plant mix from the same sections which were then compacted in the laboratory. The mixture properties influencing cracking performance between the laborat ory specimens and the field specimens w ere analyzed. 1.2 Objectives The primary focus of this research is to compare the cracking related mixture properties of laboratory compacted plant mix specimen s to those of field compacted specimen s The mixture pro perties to be determined are: Energy Ratio (Key parameter that guides cracking performance) Fracture Energy Creep Rate Resilient Modulus Strength Creep Compliance 1.3 Scope Material property data of un aged cores from Superpave project sections have been determined by Roque et al (1999 2005) Samples of plant mix asphalt from these project sections were used in this study. Sample were reheated and compacted to an air void content of 7% (0.5%) and the properties of these samples were determined using the Superpave Indirect Tension test protocol. 1.4 Research Approach L iterature review was conducted to cover the following : general aspects of compaction, effects of reheating and compaction temperature, and effects of aging on Hot Mix Asphalt. This was foll o wed by preparation of test specimens. Lastly, specimens were tested using the indirect tension test protocol. Energy ratio was used as the

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14 primary indicator to compare the effect of compaction between laboratory specimens and field specimens.

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15 CHAPTER 2 L ITERATURE REVIEW 2.1 Background This section discusses the general considerations of compaction, research findings related to compaction and the various modes of compaction A further review of the effect of reheating and compaction temperature on asphalt specimens is looked at Finally, a review of the HMA fracture mechanics based approach used to evaluate the crack related performance of asphalt mixtures is conducted 2.2 General Considerations of C ompaction and Research Findings The process of compaction involves a reduction in volume of air in HMA mixture through the application of an external force. It is always desirable that laboratory compacted specimens should have similar properties as field compacted cores (McRae, 1957). The field compacted mixtur e should have sufficient voids to allow the asphalt cement to expand and contract as temperature changes without filling the voids resulting in flushing. The voids should be high enough to allow for some subsequent traffic induced densification during the first few years of service without the void falling below about 3 4% for dense graded mixtures. Voids in an asphalt mixture are directly related to density; thus the in place voids must be controlled to achieve acceptable range of air voids. It has been sh own that for dense graded mixtures, air voids should not be greater than 8% or fall below 3%. Gyratory compacted specimens have been shown to have a relatively uniform air void distribution as shown in Figure 2 1 It is however recognized that there are va riability between laboratory and field specimens. The main parameters which need to be controlled in order to manage the variability of the mechanical performance of the asphalt in the field are aggregate gradation

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16 changes, aggregate segregation, different ial temperature within the mat, the amount of confinement across the width of the mat, and the mode of compaction Figure 2 1. Distribution of void content in gyratory compacted specimen. [ Masad et al 1999, 2004 ] Many of the factors responsible for site variability are controlled in the laboratory to a larger extent except the mode of compaction. There have been many research aimed to simulat e field compaction in the laboratory. Key amongst them is t he S trategic Highway Research program which recommends t he use of the gyratory compactor as the preferred means of asphalt mixture compaction (Sousa et al.1991; Harvey and Monismith 1993). Gibb (1996) found that in terms of permanent deformation, vibratory compacted specimens generally produced results which we re closer to site cores than steel roller compacted specimens. From their research, it was also found that rolling wheel compaction represents most closely field cores in terms of aggregate structure. Also, their research indicated that kneading compactor produces specimen with the strongest aggregate structure, while gyratory compaction produces the weakest specimens. Hartman et al (2001) compared the indirect stiffness values of specimens

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17 manufactured from five laboratory methods of compaction with site cores and found that steel roller compacted specimens were of comparable stiffness with those of the site cores. Alistair et al (2009) looked at the effect of compaction mode on the mechanical performance and conclude d that mold based compaction methods s uch as gyratory and vibratory, generally produce stiffer specimens with higher resistance to permanent deformation when compared to field specimens of comparable air voids. Von Quintus et al (1991) investigated the differences between laboratory compactio n methods as a part of the Asphalt Aggregate Mixture Analysis study in the NCHRP project. Five laboratory compaction methods namely Texas gyratory compactor, ASTM kneading compactor, Arizona vibratory/kneading compactor, Marshall hammer and steel roller we re examined to decide the method, which most closely simulates actual site condition. From their report, it is found that specimens compacted by the Texas gyratory compactor showed similar behavior to actual site cores in terms of mechanical properties. It should be noted that although the research of Von Quintus et al successfully compared five laboratory compaction methods, the cores taken from sites showed relatively higher air voids than the laboratory compacted specimens. Button et al (1994) examined the correlation between field cores and laboratory compacted specimens. They also looked at compaction methods most like actual site compaction. In their study, field cores were obtained from five different sites, whereas specimens were manufactured using four laboratory compaction methods (i.e. Texas gyratory, Exxon rolling wheel, Elf kneading and Marshall Hammer ). These were examined through both mechanical tests and s tatis ti cal analysis. Their research concluded that Texas gyratory compactor is the most suitable compaction method to simulate site

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18 compaction. The Exxon rolling compactor and Elf linear kneading compactor often simulate the behavior of actual site cores. However specimens compacted by Exxon rolling wheel compactor did not have similar air vo id contents to other laboratory compacted specimens. Therefore the specimens were not comparable with field cores. 2.3 Laboratory Compaction M ethods 2.3.1 Gyratory C ompactor of compaction was further developed and applied by the Army Corps of Engineers and the Central Laboratory for Bridges and Roads (LCPC) in France. One of the final products of the SHRP was t he Superpave mix design method with the Superpave Gyratory Compactor being a key component of the mix design procedure. The Superpave Gyratory Compactor was modified from the Texas Gyratory Compactor to perform several goals: Realistically compact mix specimens to densities achieved under actual pavement climate and traffic loading conditions; Capable of accommodating large aggregates; Capable of measuring compactibility so that potential tender mix behavior and similar compaction problems could be identified; Portable enough to allow quality control and quality assurance in mixing facility Figure 2 2 below shows a schematic diagram of a Superpave Gyratory Compactor (SGC) The SGC is a mechanical compaction device and is basically composed of the parts shown in Figure 2 2. The gyratory motion of the SGC applies two simultane ous stresses during compaction: one is the constant compression stress and the other is a shearing stress which produces a kneading action on the specimen.

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19 Fig ure 2 2 Schematic diagram of Superpave Gyratory Compactor ( Graph courtesy of Jinsong Chen) Th e compaction effort applied to the sample by the SGC is controlled by three parameters, namely vertical pressure angle of gyration and number of gyrations. Typically an angle of 1.25 degrees is used. The number of gyrations applied depends on the traffic level. Compaction automatically stops when the desired number of gyrations or height of specimen is reached. The specimen height is constantly monitored during compaction, which provides a measure of specimen density throughout the compaction procedure. 2. 3.2 Vibratory Compactor Vibratory compaction is also used to produce laboratory asphalt mixture specimens. Cooper et al (1985, 1991) used a vibratory hammer to develop the new Hot Mix asphalt mixture design method aimed at improving on previous methods. T hey applied a vibratory hammer in the Percentage refusal Density test. It was found from their research that specimens manufactured by the percentage density equipment were similar to cores taken from the field, in terms of density. Hunter et al (2004) de scribed that the vibratory hammer is often used in place of the Marshall compactor because it is

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20 easier to achieve target bulk density and void contents. It has a disadvantage in its application in that the quality of compaction depends on the operator 2.3 .3 Kneading Compaction The compaction method used by Hveem in his mix design procedure is kneading compaction. Kneading compaction applies forces through a roughly triangular shaped foot that covers only a portion of the specimen face. Compacted forces by tamps are applied uniformly on the free face of the specimen to achieve compaction. The partial face allows particles to move relative to each other, creating a kneading action that densifies the mix. Three different kneading compactors include the Califor nia kneading compactor, Linear kneading compactor and the Arizona knea ding compactor. (Philip B et al. 1994) 2.3.4 Impact Compaction Impact compaction is the oldest method of laboratory compaction. Marshall developed the mechanical Marshall hammer to simul ate impact type compaction. The number of blows applied to each face of the specimen (35 50 and 75 blows) was tied to general traffic levels. Higher energy levels (blows) were used for higher traffic levels. Unfortunately, different densities, because of the variability in Marshall hammers (mechanical, rotating and manual hammers), will result when these compaction blows are applied. (Philip B et al. 1994) 2. 4 Effect of R eheating on C ompact ed S pecimens Studies have been conducted to evaluate the effect of reheating and control of test temperature on compaction of asphalt mixtures. This is important because the viscosity of asphalt cement changes with temperature. A study conducted at the University of Wisconsin Madison under NCHRP 9 10, showed that there wa s little change in density

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21 with change in compaction temperature. The data showed that, though viscosity changed by three poises, between temperatures of 80C and 155C, compaction temperature had little to no effect on volumetric properties of the compact ed samples. Further evaluation was conducted using different modes of laboratory compaction (i.e. Marshall, Hveem) along with the Superpave G yratory C ompactor (SGC) at three different temperatures. They observed that SGC was the least sensitive to temperat ure change as can be observed in Figure 2 3 below: Fig ure 2 3 Effect of temperature on a ir v oids measured after compaction using different compaction methods for HMA containing a f ine crushed g ravel m ixture. [ Graph courtesy University of Wisconsin Madis on under NCHRP 9 10 ] 2. 5 Aging Effect on Asphalt Mixtures The stiffness of the asphalt mixture is affected by the aging phenomenon. To be able to characterize asphalt mixtures adequately requires that the samples are sufficiently simulating the in place pr operties of the mixture. The aging process in the field is affected by the amount of densification, the after construction air void and the production temperature. There are two types of aging process in the laboratory: 1. the

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22 short term oven aging which s imulates the change in stiffness during the production, laying and compaction stage. 2. The Long term oven aging which simulates the changes in stiffness after several years of oxidation, traffic densification and moisture damage. Superpave mix design requ ires that for the short term oven aging, the mixture be conditioned at a temperature equal to the expected compaction temperature for two hours after mixing and prior to compaction. For Long term oven aging, the compacted sample should be left in an oven f or an extended period of time (five days) to simulate the in service aging in the field. 2. 6 Prediction of Cracking Performance of Asphalt Mixtures Cracks that occur in HMA pavement are due to stresses, moisture damage of HMA, aging of HMA and inadequat e support from underlying layers. Asphalt mixtures can be evaluated for their cracking performance using the HMA fracture mechanics approach. The Indirect Tensile test (IDT) protocol is one method of determining the fatigue characteristics of HMA because i t allows for thin specimens of asphalt cored from the field or compacted in the laboratory to be tested. The Resilient Modulus, M R the creep compliance and the strength parameters of the HMA specimen can be determined from the IDT test. Research by Hiltun en and Roque (2004) shows that low temperature or thermal cracking can be analyzed from standard IDT test device. The resilient modulus is the first parameter obtained from the IDT test protocol. It is a measure of the materials stiffness and it is define d as the ratio of the applied stress to the recoverable strain under repeated loading. Typically, specimen diameter should range between 4 to 6 inches. The tensile stresses and strain values can be obtained at the center of the specimen from the equations stated below:

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23 ( 2 1) ( 2 2) Where t = tensile stress in the vertical diameter of the IDT specimen t = tensile strain in the center of the IDT specimen P = applied load in Ibs t = sample thickness, inches d = sample diameter in inches can be estimated from a load controlled mode system. They applied a repeated haversine wavef orm load to the specimen for a 0.1 second period followed by a rest period of 0.9 seconds. The applied load should be enough to keep the horizontal deformations within the linear viscoelastic range of 100 to 180 micro inches. The resilient modulus and Pois element analysis by Roque and Buttlar (1992) which was incorporated in the Superpave Indirect Tension Test at Low temperature (ITLT) computer program, developed by Roque et al. (1997). ( 2 3) ( 2 4)

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24 Where, M R deformation, t = Thickness, D = Diameter, C cmpl = 0. 6354 x (X/Y) 1 ratio, and X/Y = Ratio of horizontal to vertical deformation. The Creep test follows immediately after the resilient modulus test and is used to determine the creep properties of the asphalt mixture. Creep compliance and ratio are estimated using the following equations which are already incorporated in the Superpave Indirect Tension test at low temperature (ITLT) program as: ( 2 5) ( 2 6) Where, D ( cmpl, GL, v, P, and (X/Y) are already defined above. The total hori zontal deformation should be below 750 micro inches after 1000 seconds under a static load. After 100 seconds the range of horizontal deformation should be within 180 micro inches. The strength test is the last test performed on the mixtures. The tensile s trength, the failure strain and the fracture energy can be estimated from this test. The maximum tensile strength is calculated as follows: ( 2 7) Where, S t = maximum indirect tensile strength, P = Failure Load at first crack, C sx = 0.948 0.01114 x (b/D) 0.2693 x v + 1.436(b/D) x v, b = Thickness, D = Diameter and

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25 From the strengt h and resilient modulus test, the fracture energy and dissipated creep strain energy can be determined. The dissipated creep strain energy to failure is the difference between Fracture energy and the elastic energy as shown in the stress strain curve in Fi gure 2 4 below Fig ure 2 4 Determination of f racture e nergy [ Graph courtesy Chun S. 2011] Roque et al also suggested the energy ratio criterion based on their investigation of field samples. The concept was based on the fact that higher creep compliance does not necessarily imply that cracks initiate or propagate more quickly in mixtures. This criterion states that the energy ratio must be greater than 1.0 for the mixture to be acceptable. They defined the energy ratio as the ratio between the final and minimum dissipated creep strain energy. Table 2 1 shows the minimum energy ratio values for various traffic conditions. Table 2 1. Energy based m ixture specification c riteria Traffic ESALs/year x 1000 Minimum Energy Ratio <250 1 <500 1.3 <1000 1.95

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26 CH APTER 3 TEST PROCEDURE 3.1 Sample Preparation and Aging Plant mix asphalt mixtures from the five different Superpave project sections were reheated for two hours to reach their respective mix ing temperatures To ensure uniformity in heating each sample wa s stirred after an hour of heating. The maximum specific gravity (G mm ) of each of the project sections was determined by the Superpave monitoring project group at University of Florida and their values were used in the subsequent determination of air voids The tables below summarize the mixture information for the Superpave project s under investigation. Table 3 1 Mixture i nformation Project No Mix Type Sample Weight (g) Gyrations @ N des LAB DENSITY Ib/ft 3 COMPACTION TEMPERATURE ( F) % AIR VOID @ OAC 8 Co arse SP 12.5 recycle 4500 96 142.5 300 4 9 Fine FC 6 W/GTR 4750 75 147.4 300 4 10 FC 6 ARB 5 5040 75 154.6 300 4.03 11 Coarse SP 12.5 recycle 4700 125 147.3 325 4 12 FC 6 4900 75 152.1 300 3 5 Table 3 2 Binder i nformation for project s ections Proje ct Binder Type Mixture Type Traffic Level 8 PG 76 22 12.5 Coarse D 9 ARB 5 FC 6 C 10 ARB 5 FC 6 B 11 PG 76 22 12.5 Coarse E 12 ARB 5 FC 6 C

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27 The aggregate gradation for each project section for both the laboratory and the field specimens are summariz ed in Appendix A and B For the laboratory specimens, DASR porosity was calculated based on the design gradations. Aggregates were extracted from the in place field specimens and a sieve analysis was run to determine its DASR porosity. Table 3 3 compares the laboratory (design) and the in place (field) gradation parameters to assess whether compaction has changed the gradation characteristics of the field specimens. It is evident from the analysis that compaction did not affect the gradation characteristic s of the aggregates. Table 3 3 Comparison of DASR gradation parameters Project DASR (mm) DASR porosity (%) DASR (mm) DASR porosity (%) laboratory Field 8 4.75 2.36 50 4.75 2.36 54.5 9 4.75 1.18 53.6 4.75 1.18 51.5 10 9.5 1.18 43.1 9.5 1.18 42 1 1 4.75 1.18 41.4 4.75 1.18 41.6 12 4.75 2.36 52.8 4.75 1.18 44.1 3. 2 Compaction and Determination of Air Void The process of compaction was to aid in the determination of the bulk specific gravity of the samples from which the percent air voids ca n be estimated. The Superpave Gyratory compactor was used for this project. It applies a ram pressure of 600KPa on a 150mm diameter specimen at angle of 1.25 degrees. The reheated materials were poured into the preheated mold with a paper disc at the botto m. The mold was then loaded into the gyratory compactor and the required input data was recorded onto the computer system. Compaction was based on the number of gyrations to achieve the design target air void [refer to Table 3 4 ]. The number of gyrations c orresponding to 7.5% air void was determined after calculations and the specimens

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28 were compacted to achieve the laboratory target air void for pills of 7.5% (0.5). A target air void of 7% (0.5) was expected after the pills are cut for testing. To determi ne the bulk specific gravity of the specimens, the weight of the dry specimen, the submerged and the saturated surface dry (SSD) is found. The bulk specific gravity of each of the specimens is calculated as follows: ( 3 1 ) Table 3 4 below shows the percent air void for each of the specimens tested Table 3 4 Number of gyrations and % a ir v oids Project Number of Gyrations weight in air (g) weight submerge d (g) We ight SSD (g) G mb G mm Cut Specimen Air Voids (%) 8 25 1315.7 723.9 1319.8 2.208 2.376 7.07 1323.1 730.3 1327.9 2.214 2.376 6.82 1404.0 776.7 1409.2 2.220 2.376 6.58 9 22 1323.1 750.5 1324.5 2.305 2.473 6.79 1385.7 787.8 1388.5 2.307 2.473 6.72 1424.6 809.5 1427.0 2.307 2.473 6.71 10 30 1411.2 834.8 1412.2 2.444 2.620 6.72 1502.3 888.6 1503.3 2.444 2.620 6.72 1486.4 878.9 1487.4 2.443 2.620 6.77 11 45 1245.5 710.1 1248.5 2.313 2.484 6.87 1385.0 789.5 1389.3 2.309 2.484 7.04 1243.4 707.3 1246.0 2.308 2.484 7.08 12 15 1399.8 816.8 1401.0 2.396 2.564 6.55 1421.9 829.9 1424.3 2.392 2.564 6.70 1265.4 737.4 1266.5 2.392 2.564 6.72 3. 3 Cutting After the specimens have been compacted and dried out enough, a cutting device was used to slice the pills into the desired thicknes s of about 1.5 inches. Figure 3 1

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29 below show the cutting device used for this project. Specimens were put into the de humidifier for at least 48 hours to remove all the moisture absorbed into the mix. Fig ure 3 1 S pecimens in cutting machine [Photo courtesy o f author ] 3. 4 Attaching Gage Points The gauge points are the pointers on which the strain gauges would be mounted. Gauge points were fixed on to the specimens at positions D/4 where D is the diameter of t he specimen. This is a consideration developed by Dr Roque (AAPT, 1992). Attaching the gauge points required the use of a vacuum pump shown in Figure 3 2 which allows for easy fixing onto the specimen and a strong adhesive which makes for difficult remov al of gauges from the specimens. 3. 5 Indirect Tension Test Procedure After attaching the gauge points, the specimens were placed in the IDT environmental chamber to condition the specimens to a testing temperature of 10C. The test protocol comprises of t he resilient modulus, creep compliance and strength test. These tests provided information on the properties of the asphalt mixtures compacted in the laboratory. The Material Testing System (MTS) shown in Figures 3 3

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30 was used for the testing and the test c onfiguration was set to the indirect tension test mode. Fig ure 3 2. Specimen in vacuum pump [Photo courtesy o f author ] Figure 3 3 Material Testing System [Photo courtesy o f author ] 3. 6 Resilient Modulus Test The resilient modulus is the ratio o f the applied stress to the recoverable strain under repeated loading. The test is performed in a load controlled mode by applying a repeated haversine waveform load to the specimen for 0.1 seconds followed by a rest period of 0.9 seconds. The resilient mo a three dimensional finite element analysis by Roque and Buttlar (1992) which was

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31 incorporated in the Superpave Indirect Tension Test at Low temperature (ITLT) computer program, developed by Roque et al. (19 97). ( 3 2 ) ( 3 3 ) Where, M R deformation, t = Thickness, D = Diameter, C cm pl = 0.6354 x (X/Y) 1 ratio, and X/Y = Ratio of horizontal to vertical deformation. 3. 7 Creep Compliance Test The creep test followed after the resilient modulus test. Creep compliance is a time dependent strain over a constant stress function. It can be used to evaluate the rate of damage accumulation of asphalt mixtures. Mixture parameter values such as D o, D 1 and m value. Figure 3 4 further explains the meaning of these mixture parameters. D 1 and m value are related to each other. Fig ure 3 4 Creep compliance curve based on p ower model [Reprinted with permission from Chun S. 2011]

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32 The creep test was also performed in the load controlled mode. A static load was applied to the specimen for 1000 seconds. The deformation curve was obs erved ensuring that at 100 seconds, the deformation was within 100 150 micro inches and at 1000 seconds, the total horizontal deformation was less than 750 micro inches. The creep compliance was calculated based on the equations stated below: ( 3 4 ) ( 3 5 ) Where, D ( cmpl, GL, v, P, and (X/Y) are already defined above. 3. 8 Strength T est The strength test is a destructive test and is controlled in a displacement mode. An application of 50mm/min displacement is applied to the specimen until failure. One advantage of the Superpave Indirect test is the fact that failure is known a priori and Figure 3 5 shows a typical failure mode of the specimens. The maximum tensile strength is calculated as follows: ( 3 6 ) Where, S t = maximum indirect tensile strength, P = Failure Load at first crack, C sx = 0.948 0.01114 x (b/D) 0.2693 x v + 1.436(b/D) x v, b = Thickness, D = Diameter and v =

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33 Fig ure 3 5 T ypical f ailure mode of IDT test specimens [Photo courtesy o f author ]

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34 CHAPTER 4 TEST RESULTS AND ANA LYSIS 4.1 Background I ndirect tension test results were analyzed using the ITLT computer program software developed by Roque et al (1999). The effect of compaction on mixture properties for all the project sections were assessed with due consider ation to the effect of air voids in mixtures. Comparison between the laboratory compacted specimens and the field compacted specimens wa s made for the following mi xture properties : R esilient modulus, strength, creep rate and creep compliance, fracture energy failure strain and the energy ratio. A T test analysis was done to assess the difference between the laboratory and the field compacted specimens for each pro ject section for the various mixture properties using the Statistical Package for the Social Sciences ( SPSS ) software Due to insufficient data, the T test was not conducted on creep rate, creep compliance, energy ratio, and fracture energy. 4.2 Comparison between Field and Lab Compacted Air Void Figure 4 1 shows a comparison between the field air void and laboratory air void Except for project 10, the laboratory compacted specimens produced higher air void content than the field compacted specimens. Gener ally, higher air voids would result in accelerating oxidative aging which would increase the embrittl ement of the mixture thus causing a reduction in failure strain. Correlation between field and laboratory specimens showed a poor correlation between the t wo as shown in Figure 4 2 below. Table 4 1 shows a summary of the results between the field and laboratory mixture properties at 10C

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35 Fig ure 4 1 Comparison between f ield and l aboratory a ir v oid [Photo courtesy o f author ] Fig ure 4 2. Correlation b etween lab and field c ompacted specimens [ Photo courtesy o f author ]

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36 Table 4 1 Comparison between f ield and l aboratory m ixture p roperties (10C) Creep Compliance in (1/Gpa) Strength in (MPa) Resilient Modulus (GPa) Failure strain (microstrain) Fracture Energy (KJ/m 3 ) Energy Ratio Project 8 Lab 1.426 2.08 10.41 1127.54 1.6 1.76 Field 0.829 2.23 11.55 937.92 1.4 2.69 Project 9 Lab 0.849 2.42 11.84 1035.75 1.8 3.43 Field 0.658 2.39 12.13 1268.68 2.3 5.79 Project 10 Lab 0.727 3.02 16.59 901.54 1.8 3.4 3 Field 0.905 3.01 14.64 1178.81 2.45 3.86 Project 11 Lab 1.335 2.97 13.94 1179.76 2.4 2.5 Field 1.295 3.27 13.39 1701.28 3.95 3.99 Project 12 Lab 2.457 2.31 10.50 1831.91 3.1 2.02 Field 2.257 2.40 10.32 2369.74 4.3 3.02 4.3 Resilient Modulus Th e resilient modulus which measures the elastic stiffness of the material is shown in Figure 4 3 A t test was conducted to investigate the differences between laboratory and field resilient modulus. From the results of the T test shown in Appendix C, it ca n be seen that laboratory and field resilient modulus were significantly different for all the project sections at 10% level of significance with the exception of project 12. Furthermore, a linear regression analysis was conducted to determine whether ther e is any correlation between laboratory and field compacted specimens. From Figure 4 4, it

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37 can be seen that there is a good correlation between the field and laboratory resilient modulus with a correlation coefficient (R Square) of 0.91. The regression equ ation is Field M R =1.5016*Laboratory M R 5.9734 Fig ure 4 3 Comparison between f ield and l aboratory r esilient m odulus [ Photo courtesy o f author ] Figure 4 4. Correlati on between f ield and l aboratory specimens [ Photo courtesy o f author ]

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38 4.4 Creep Compli ance /Creep Rate Creep compliance indicates the ability of the mixture to relax stresses. Generally, the higher the creep compliance the higher the mixtures ability to relax stresses at a faster rate. Higher creep compliance also gives an indication of perm anent damage. Figure 4 5 shows results of the creep compliance between the field and the laboratory compacted specimens. Except for Project 10, the other project sections showed a higher rate of damage accumulation for the laboratory compacted specimens wh ich could explain why it resulted in a low er energy ratio. The higher rate of damage accumulation for the laboratory specimens could be attributed to the effect of binder aging for the laboratory specimens. Creep rate or rate of creep compliance is related to rate of damage and showed similar trends as illustrated in Figure 4 6 A regression analysis between the field and the laboratory specimens showed that there is good correlation between the field and the laboratory creep compliance and creep rate with a correlation coefficient of (R Square) of 0.8287 and (R Square) of 0.8436 respectively. Fig ure 4 5 Comparison between field and laboratory creep c ompliance [ Photo courtesy o f author ]

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39 Fig ure 4 6 Comparison between f ield a nd laboratory c ree p r ate [ P hoto courtesy o f author ] Fig ure 4 7 Creep rate correlation between field and l aboratory specimens [ Photo courtesy o f author ]

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40 Figure 4 8. Creep compliance correlation between field and laboratory specimens [ Photo courtesy o f author ] 4.5 Tensile Stre ngth The tensile strength of the material is the stress at which it fractures. Figure 4 9 illustrates the comparison between laboratory compacted and field compacted specimens. As can be observed, the strength parameters between the field and the laborator y compaction are almost the same. A T test analysis also shows that at 10% level of significance, there was no significant difference in strength between the laboratory and the field compacted specimens for all the project sections as shown in Appendix C. a good correlation was found between the field and the laboratory compacted specimens with a correlation coefficient of R 2 =0.9141 as shown in Figure 4 10.

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41 Fig ure 4 9. Comparison between Field and Laboratory Strength [Photo courtesy of author ] Figure 4 10. Strength correlation between lab and field compacted specimens [Photo courtesy of author]

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42 4.6 Fracture Energy Fracture energy is known to be a good indicator to predict the cracking performance of asphalt pavement and it is the ability of the mixtur e to resist damage without fracturing. Figure 4 11 shows the effect of laboratory and field compacted specimens on fracture energy. It can be observed that in four out of the five project sections the laboratory fracture energy w ere significantly lower th an the field. It can be posited that the compaction effect predicts much conservative values than the effect in the field. The difference in gradation between the laboratory and the field specimens were not significant as shown in Appendix A and B and ther efore could not have accounted for the difference. The laboratory specimens could have aged during storage and reheating the specimens to the compaction temperature could have also increased the aging process which may explain the observed trend. There was also a very good correlation between the lab and the field compaction for the entire project section as seen in Figure 4 12 with a correlation coefficient of R 2 = 0.8728 Fig ure 4 11. Comparison betw een field and laboratory fracture e nergy [Photo courte sy of author]

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43 Figure 4 12. Fracture energy correlation [Photo courtesy of author] 4.7 Failure Strain Failure strain is related to the brittleness of the mixture. A lower failure strain is characterized by a very stiff mixture and thus very brittle. It a lso informs of the mixtures aging condition or susceptibility to oxidative aging. Laboratory samples may have ag ed res ulting in it having lower values of failure strain. The process of reheating to reach the compaction temperature may also accelerate the a ging process and hence the reduction in failure strains for laboratory mixtures than the field specimens. Figure 4 13 shows the comparison between the field and the laboratory compacted specimens. Except for project 8, all the other project sections showed a significant difference between the field and the laboratory specimens at a significance level of 10% from the T test analysis shown in Appendix C. There was a good correlation between the laboratory and the field compacted specimens for the entire proje ct section as seen in Figure 4 14 with a correlation coefficient of R 2 =0.7874

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44 Fig ure 4 13. Comparison between field and l aboratory f ailure strain [Photo courtesy o f author ] Figure 4 14. Failure strain correlation [Photo courtesy o f author ]

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45 4.8 Energy Ratio Energy ratio illustrates best the trend between the laboratory compacted specimen and the field compacted specimens. Energy ratio seems to be the most sensitive parameter that defines the effect of compaction on asphalt mixtures. It was always lower for the laboratory specimens compared with the field specimens as shown in Figure 4 15 All the laboratory compacted mixtures however met the minimum requirement of 1.0 for a mixture to be accepted. The relatively lower energy ratio value for the field c ompacted specimen in Project 10 could be explained by its higher air void content as seen in Figure 4 1. The correlation between field and laboratory energy ratio shown in Figure 4 16 highlights this trend as project 10 was far from the equality line The energy ratio parameter generally showed a good correlation between the field and the laboratory for the entire project sections as seen in Figure 4 16 except for project 10, which has been explained above with a correlation coefficient of R 2 =0.6626. F ig ure 4 15. Comparison between f ield and l aboratory f ailure strain [Photo courtesy o f author ]

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46 Figure 4 1 6 Energy ratio correlation [Photo courtesy o f author ]

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47 CHAPTER 5 CONCLUSION 5.1 Summary of Findings This chapter provides the findings of this repor t and the issues arising out of the research. Laboratory compacted plant mix specimens were tested at 10C to evaluate its mixture properties. The results of the evaluation were compared with field compacted specimens at same temperature. It was evident fr om the experimental procedure that the energy ratio which is a function of the fracture energy and the creep compliance is the key parameter to compare the compaction effect of laboratory and field. It was observed that laboratory compaction generally prod uces conservative predictions even though they met the minimum requirements needed for an acceptable mixtu re. The results also confirmed that resilient modulus and strength parameters may not be ideal for crack performance prediction. 5.2 Issues Severa l issues may have affected the validity of the results. Due to the unavailability of materials, comparisons were only made using five project sections. 5 3 Future Research Future research into this area would be helpful and informative using the original Superpave aggregates and binders for a wide range of project sections for different layers and at different testing temperatures. Binder extraction from the laboratory compacted specimens should be made to assess its fracture performance using the newly d eveloped fracture test protocol at the University of Florida.

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48 APPENDIX A LABORATORY GRADATION Table A 1. Aggregate g radation for project 8 Milled Material S1 A Stone S1 B Stone New Mill Screening Sand JMF Control Points Restricted Zone No 10% 15% 50% 10% 15% JMF CP RZ 19 100 100 100 100 100 100 100 12.5 98 60 100 100 100 94 90 100 9.5 95 39 100 100 100 90 4.75 73 7 52 97 100 59 2.36 59 6 8 65 99 32 28 58 39.1 39.1 1.18 50 5 3 48 89 25 25.6 31.6 600 46 4 3 37 50 18 19.1 23.1 300 40 3 3 2 6 20 12 150 27 3 2 18 7 7 75 10.9 3 2 8.7 1 4.5 2 10 Table A 2. Aggregate g radation for project 9 # 67 Stone #89 Stone W 10 Screening M 10 Screening Local Sand JMF Control Points Restricted Zone No 15% 15% 20% 40% 10% JMF CP RZ 19 100 100 100 100 100 100 100 12.5 65 100 100 100 100 95 90 100 9.5 38 93 100 100 100 90 4.75 10 33 93 94 100 73 2.36 4 5 63 74 100 54 28 58 39.1 39.1 1.18 2 3 40 53 92 39 25.6 31.6 600 2 2 23 37 85 29 19.1 23.1 300 2 1 12 26 55 19 150 2 1 6 17 10 9 75 1.3 0.9 3.6 10.8 1.6 5.5 2 10

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49 Table A 3. Aggregate g radation for project 10 #78 Stone #89 Stone W 10 Screening M 10 Screening Sand JMF Control Points Restricted Zone No 30% 10% 20% 30% 10% JMF CP RZ 19 100 100 100 100 100 100 100 12.5 93 100 1 00 100 100 98 90 100 9.5 60 100 100 100 100 88 4.75 10 35 100 100 100 67 2.36 4 5 64 68 100 45 28 58 39.1 39.1 1.18 2 4 44 50 100 35 25.6 31.6 600 1 3 27 40 88 27 19.1 23.1 300 1 2 15 23 60 16 150 1 1 8 17 12 8 75 1 1 4 12 2 5.4 2 10 Table A 4. Aggregate g radation for project 11 Milled Material #67 Stone #89 Stone W 10 Screening M 10 Screening JMF Control Points Restricted Zone No 15% 17% 30% 26% 12% JMF CP RZ 19 100 98 100 100 100 100 100 12.5 99 56 100 100 100 92 90 100 9.5 9 8 35 96 100 100 87 4.75 83 4 40 90 90 59 2.36 64 2 6 63 64 36 28 58 39.1 39.1 1.18 54 1 5 38 43 25 25.6 31.6 600 46 1 4 25 30 18 19.1 23.1 300 38 1 3 14 21 13 150 24 1 2 6 14 8 75 12.9 1 1 3.9 10.4 4.7 2 10

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50 Table A 5. Aggregate g radat ion for project 12 #78 #89 W 10 Screenings Sand JMF Control Points Restricted Zone No 25% 28% 27% 20% JMF CP RZ 19 100 100 100 100 100 100 12.5 93 100 100 100 98 90 100 9.5 60 100 100 100 90 4.75 10 35 100 100 59 2.36 4 5 66 100 40 28 58 39.1 39.1 1.18 2 3 46 100 34 25.6 31.6 600 1 2 29 89 26 19.1 23.1 300 1 2 17 28 11 150 1 1 9 6 4 75 1 1 4.5 1 3.5 2 10

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51 APPENDIX B FIELD GRADATION Table B 1. Aggregate g radation for project 8 Gradation Control Points Restricted Zone No CP R Z 19 98.58 100 12.5 92.32 90 100 9.5 87.62 4.75 61.88 2.36 35.95 28 58 39.1 39.1 1.18 25.77 25.6 31.6 600 18.33 19.1 23.1 300 11.75 150 10.34 75 5.82 2 10 Table B 2. Aggregate g radation for project 9 Gradation Control Points Rest ricted Zone No CP RZ 19 99.37 100 12.5 95.30 90 100 9.5 91.23 4.75 74.17 2.36 52.42 28 58 39.1 39.1 1.18 37.38 25.6 31.6 600 28.93 19.1 23.1 300 18.23 150 8.80 75 5.43 2 10

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52 Table B 3. Aggregate g radation for project 10 Gra dation Control Points Restricted Zone No CP RZ 19 100 100 12.5 99.63 90 100 9.5 89.21 4.75 67.29 2.36 49.18 28 58 39.1 39.1 1.18 34.48 25.6 31.6 600 26.07 19.1 23.1 300 16.24 150 8.88 75 5.42 2 10 Table B 4. Aggregate g radation f or project 11 Gradation Control Points Restricted Zone No CP RZ 19 97.27 100 12.5 90.51 90 100 9.5 86.48 4.75 61.09 2.36 37.45 28 58 39.1 39.1 1.18 24.61 25.6 31.6 600 17.44 19.1 23.1 300 12.13 150 7.50 75 4.88 2 10

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53 Table B 5. Aggregate g radation for project 12 Gradation Control Points Restricted Zone No CP RZ 19 100 100 12.5 99.28 90 100 9.5 91.78 4.75 58.39 2.36 40.44 28 58 39.1 39.1 1.18 31.62 25.6 31.6 600 25.61 19.1 23.1 300 13.01 150 5.60 75 3. 5 3 2 10

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54 APPENDIX C T TEST DATA Table C 1. Project 8 Mean N Std. Deviation Std. Error Mean t statistic Sig. (2 tailed) Resilient Modulus Laboratory 10.407 3 0.032 .01856 61.605 .00026 Field 11.550 3 0.000 0.00000 Strength Laboratory 2.077 3 0.110 .06333 2.421 .13652 Field 2.230 3 0.000 0.00000 Creep Compliance Laboratory 1.4260 a 1 0.000 0.00000 N.A N.A Field .8290 a 1 0.000 0.00000 Creep Rate Laboratory 3.6000E 009 a 1 0.000 0.00000E+00 N.A N.A Field 1.8900E 009 a 1 0.000 0.00000E+ 00 Failure Strain Laboratory 1127.535 4 236.978 118.48885 1.600 .20785 Field 937.920 4 0.000 0.00000 Fracture Energy Laboratory 1.6000 a 1 0.000 0.00000 N.A N.A Field 1.4000 a 1 0.000 0.00000 Energy Ratio Laboratory 1.7600 a 1 0.000 0.00000 N.A N .A Field 2.6900 a 1 0.000 0.00000 a. The correlation and t cannot be computed because the standard error of the difference is 0. Table C 2. Project 9 Mean N Std. Deviation Std. Error Mean t statistic sig (2 tailed) Resilient Modulus Laborator y 11.8433 3 .05033 .02906 9.865 .0101 Field 12.1300 3 0.00000 0.00000 Strength Laboratory 2.4133 3 .04163 .02404 .971 .434 Field 2.3900 3 0.00000 0.00000 Creep Compliance Laboratory .8490 a 1 0.00000 0.00000 N.A N.A Field .6580 a 1 0.00000 0.000 00 Creep Rate Laboratory 1.8800E 009 a 1 0.00000E+00 0.00000E+00 N.A N.A Field 1.5200E 009 a 1 0.00000E+00 0.00000E+00 Failure Strain Laboratory 1035.7525 4 139.57936 69.78968 3.338 .0445 Field 1268.6800 4 0.00000 0.00000 Fracture Energy Labora tory 1.8000 a 1 0.00000 0.00000 N.A N.A Field 2.3000 a 1 0.00000 0.00000 Energy Ratio Laboratory 3.4300 a 1 0.00000 0.00000 N.A N.A Field 5.7900 a 1 0.00000 0.00000 a. The correlation and t cannot be computed because the s tandard error of the differe nce is 0.

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55 Table C 3. Project 10 Mean N Std. Deviation Std. Error Mean t statistic Sig (2 tailed) Resilient Modulus Laboratory 16.5933 3 .03512 .02028 96.338 .000 Field 14.6400 3 0.00000 0.00000 Strength Laboratory 3.0200 3 .34511 .19925 .05 0 .965 Field 3.0100 3 0.00000 0.00000 Creep Compliance Laboratory .7270 a 1 0.00000 0.00000 N.A N.A Field .9050 a 1 0.00000 0.00000 Creep Rate Laboratory 1.9000E 009 a 1 0.00000E+00 0.00000E+00 N.A N.A Field 2.7200E 009 a 1 0.00000E+00 0.00000E+00 Failure Strain Laboratory 901.5400 4 118.59635 59.29817 4.676 .018 Field 1178.8100 4 0.00000 0.00000 Fracture Energy Laboratory 1.8000 a 1 0.00000 0.00000 N.A N.A Field 2.4500 a 1 0.00000 0.00000 Energy ratio Laboratory 3.4300 a 1 0.00000 0.0000 0 N.A N.A Field 3.8600 a 1 0.00000 0.00000 a. The correlation and t cannot be computed because the standard error of the difference is 0. Table C 4. Project 11 Mean N Std. Deviation Std. Error Mean t statistic Sig.(2 tailed) Resilient Modulus Laboratory 13.9367 3 .05508 .03180 17.192 .003 Field 13.3900 3 0.00000 0.00000 Strength Laboratory 2.9667 3 .21939 .12667 2.395 .139 Field 3.2700 3 0.00000 0.00000 Creep Compliance Laboratory 1.3350 a 1 0.00000 0.00000 N.A N.A Field 1.2950 a 1 0.00000 0.00000 Creep Rate Laboratory 3.6000E 009 a 1 0.00000E+00 0.00000E+00 N.A N.A Field 3.8300E 009 a 1 0.00000E+00 0.00000E+00 Failure Strain Laboratory 1179.7550 4 181.61080 90.80540 5.743 .010 Field 1701.2800 4 0.00000 0.00000 Fracture E nergy Laboratory 2.4000 a 1 0.00000 0.00000 N.A N.A Field 3.9500 a 1 0.00000 0.00000 Energy Ratio Laboratory 2.5000 a 1 0.00000 0.00000 N.A N.A Field 3.9900 a 1 0.00000 0.00000 a. The correlation and t cannot be computed because the standard error of the difference is 0.

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56 Table C 5. Project 12 Mean N Std. Deviation Std. Error Mean t statistic Sig. (2 tailed) Resilient Modulus Laboratory 10.5000 3 .11358 .06557 2.745 .11 1 Field 10.3200 3 0.00000 0.00000 Strength Laboratory 2.3167 3 .11930 .06888 1.210 .350 Field 2.4000 3 0.00000 0.00000 Creep Compliance Laboratory 2.4570 a 1 0.00000 0.00000 N.A N.A Field 2.2570 a 1 0.00000 0.00000 Creep Rate Laboratory 8.210 0E 009 a 1 0.00000E+00 0.00000E+00 N.A N.A Field 6.9300E 009 a 1 0.00000E+00 0.00000E+00 Failure Strain Laboratory 1831.9100 4 453.09854 226.54927 2.374 .098 Field 2369.7400 4 0.00000 0.00000 Fracture Energy Laboratory 3.1000 a 1 0.00000 0.00000 N. A N.A Field 4.3000 a 1 0.00000 0.00000 Energy Ratio Laboratory 2.0200 a 1 0.00000 0.00000 N.A N.A Field 3.0200 a 1 0.00000 0.00000 a. The correlation and t cannot be computed because the standard error of the difference is 0.

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57 LIST OF REFERENCE S transportation engineering. sured University of Nottingham. Masad, E., M., Properties of Laboratory Compacted Aspha University of Nottingham, United Kingdom. Mix Asphalt Materials, Mixture Philip B. B., Mahboub, K.C., and Huber, G.A. (1994), Compaction of Hot of Transportation Research Board, National Research Council, Washington, D.C., Vol. 1454, pp.144 153. Sousa, J.B., Deacon, J. A., and Monismith, Compaction Method on Permanent Deformation Characteristics of Asphalt 60, pp. 533 585. Studies of Bituminous Paving pp.117 153.

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58 BIOGRAPHICAL SKETCH Michael Ankamah Bekoe is pursuing his c ivil e ngineering ( m aterials) at the University of Flor ida. He was born in Ghana and obtained his degree in the same field at the Kwame Nkrumah University of Science and Technology in 2005 Before coming to the United States, he worked as a m aintenance engineer with the Department of Urban Roads, a road agency under the Ministry of Roads and Highways, Ghana. He has the desire to pursue a doctorate degree in c ivil engineering (materials) and l ooks forward to that challenge.