TRB Abstracts 2003
Table of Contents
1. Development of an Efficient Hot Mix Asphalt Fracture Mechanics-Based Crack Growth
Simulator
2. An Updated Review Of SMA And Superpave Projects
3. Analysis Of Permeability And Fluid Flow In Asphalt Mixes
4. Economic Impact of Refining The Dynamic Internal Angle Of The Superpave® Gyratory
Compactor
5. Evaluation of Permeability of Superpave Asphalt Mixtures
6. An Examination of Gamma Ray Methods for Measuring Bulk Specific Gravity of Hot-Mix
Asphalt Concrete
7. Investigation Of The Tender Zone In The Compaction Of Coarse-Graded Superpave Hot
Mix Asphalt (HMA) Mixes
8. Use Of PMS Data For Performance Monitoring With Superpave As An Example
9. Workability Of Hot Mix Asphalt
10. The Effect of Volumetric Properties on Mechanical Behavior of Asphalt Mixtures
11. Georgia DOT’s Evaluation of a Remixing Paver
12. An Investigation Of Factors Influencing Permeability Of Superpave Mixes
13. Laboratory Evaluation Of The Effect Of SBS Modifier On Cracking Resistance Of Asphalt
Mixture
14. Interlayer and Design Considerations to Retard Reflective Cracking
15. Precision of Shear Tests Used for Evaluating Asphalt Mixtures
16. Superpave Laboratory Compaction Versus Field Compaction
17. Application of Infrared Imaging and Ground-Penetrating Radar for Detecting Segregation
in Hot-Mix Asphalt Overlays
18. Case Study: Preliminary Field Validation of Simple Performance Tests for Permanent
Deformation
19. Establishing the Superpave Ndesign Compaction Matrix Using Information Collected in
Northern Taiwan Area
20. New Mix-Design Procedure of Cold In-Place Recycling for Pavement Rehabilitation
21. Performance Evaluation Of Polymer Modified Superpave Mixes Using Laboratory Tests
And Accelerated Pavement Load Facility
22. The Effects of HMA Mixture Characteristics on Rutting Susceptibility
23. An Evaluation Of Use Of Rapid Triaxial Test In Quality Control Of Hot Mix Asphalt
(HMA)
24. Field Evaluation of Asphalt Additives to Control Rutting and Cracking
25. Measuring And Predicting Hydraulic Conductivity (Permeability) Of Compacted Asphalt
Mixtures In The Laboratory
26. Micro-Deval Testing Of Aggregates In The Southeast
27. Resilient Modulus, Tensile Strength, and Simple Shear Test to Evaluate Moisture
Sensitivity and the Performance of Lime in Hot Mix Asphalt Mixtures
28. Simulation of Fracture Initiation in Hot Mix Asphalt Mixtures
29. Three-Dimensional Finite Element Analysis Of Measured Tire Contact Stresses And Their
Effects On Instability Rutting Of Asphalt Mixture Pavements
30. Ultrasonic Pulse Wave Velocity Test As A Tool For Monitoring Changes In Hma Mixture
Integrity Due To Exposure To Moisture
31. Use Of Screenings To Produce HMA Mixtures
32. Aggregate Imaging System (AIMS) For Characterizing The Shape Of Fine And Coarse
Aggregates
33. Analytical Formulas for Film Thickness in Compacted Asphalt Mixture
34. Asphalt Pavement Quality Control/Quality Assurance Programs In The United States
35. Do Asphalt Mixtures Correlate Better with Mastics or Binders in Evaluating Permanent
Deformation?
36. Lessons Learned From Trucking Operations At The Ncat Pavement Test Track
37. Pavement Surface Macrotexture Measurement and Application
38. The Time-Temperature Superposition For Asphalt Mixtures With Growing Damage And
Permanent Deformation In Compression
39. A Commentary on FDOT Technician Certification Program
40. Creep Compliance of Polymer Modified Asphalt, Asphalt Mastic and Hot Mix Asphalt
41. Design, Construction And Early Performance Of Foamed Asphalt Full Depth Reclaimed
(FDR) Pavement In Maine
42. Development And Validation Of A Model To Predict Pavement Temperature Profile
43. Development Of A New Test Procedure For Determining The Bulk Specific Gravity Of Fine
Aggregate Using Automated Methods
44. Development Of A Rational Procedure For Evaluation Of Moisture Susceptibility Of
Asphalt Paving Mixes
45. Evaluation Of Infrared Ignition Furnace For Determination Of Asphalt Content
46. Evaluation Of Moisture Susceptibility Of Asphalt Mixtures Containing Bottom Ash
47. Quantitative Field Evaluation and Effectiveness of Fine Mix under HMA Base in Flexible
Pavements
48. Utilizing Pavement Evaluation Data in Rehabilitation Design in MDSHA
49. Viscoelastic, Viscoplastic, and Damage Modeling of Asphalt Concrete in Unconfined
Compression
50. Implementation of a New Ride Quality Specification in Maryland An Incentive Based
Profile Specification
51. Laboratory Evaluation of Asphalt Rubber Mixtures Using the Dynamic Modulus (E*) Test
52. Mechanistic Evaluation Of Mineral Fillers On Fatigue Resistance And Fundamental
Material Characteristics
53. Whitetopping And Hot-Mix Asphalt Overlay Treatments For Flexible Pavement: A
Minnesota Case History
54. Evaluation Of Rutting Resistance Of Superpave Mixtures With And Without Sbs
Modification By Means Of Accelerated Pavement Testing
55. Performance-Related Tests and Specifications for Cold In-Place Recycling: Lab and Field
Experience
56. Thermal Aspect of Frost-Thaw Pavement Dimensioning: In Situ Measurement and
Numerical Modeling
57. Design And Construction Of Rock Cap Roadways – A Case Study In Northeast Washington
58. Using Gyratory Compaction to Investigate Density and Mechanical Properties of RCC
59. The Change to End-Result Specifications: Where Are We Now?
60. Detection of Surface Segregation using LASER
61. Evaluation of Different Parameters for Superpave High Temperature Binder Specification
Based on Rutting Performance in the Accelerated Loading Facility at FHWA
62. A Fatigue Endurance Limit for Highway and Airport Pavements
63. Ground-Penetrating Radar: What Can It Tell about the Moisture Content of the Hot Mix
Asphalt Pavement?
64. Successful Application of GPR for Quality Assurance/Quality Control of New Pavements
65. Development and Implementation of a Continuous Vertical Track Support Testing
Technique
66. Direct Tension Tests – a Useful Tool to Study the Low Temperature Properties of Wax –
Containing Asphalt
67. Refinement Of New Generation Open-Graded Friction Course Mix Design
68. Combining Traditional and Non-Traditional NDT Techniques to Evaluate Virginia’s
Interstate 81
69. Construction-Related Variability in Mat Density Due to Temperature Differentials
70. Effectiveness Of Lime In Hot Mix Asphalt Pavements
71. Eight-Year of Field Performance of A Secondary Road Incorporating Geosynthetics at The
Subgrade-Base Interface
72. Expanded Asphalt Stabilization On The Trans-Canada Highway
73. A Pavement Management Perspective On Integrating Preventive Maintenance Into A
Pavement Management System
74. Representative Sampling For Construction Quality Control At The 2000 Ncat Pavement
Test Track
75. Field Study of the Influence of Shear Stiffness on Rutting of Asphalt Mixes
76. Traditional Fatigue Analysis of Asphalt Concrete Mixtures
77. Comparison Of Non-Destructive Testing Devices To Determine In Situ Properties Of
Asphalt Concrete Pavement Layers
78. Cost-Effectiveness of Joint and Crack Sealing
79. Crack Modeling Of Asphaltic Mixtures Considering Heterogeneity Of The Material
80. Development Of An Asphalt Aging Procedure To Assess Long-Term Binder Performance
81. Development Of Flexible Pavement Performance Prediction Model Based On Pavement
Data
82. Effects of Environmental Factors on Pavement Performance – The Initial Evaluation of the
LTPP SPS-8 Experiment
83. Fatigue Life Prediction Of Asphalt Mixes Using Viscoelastic Material Properties
84. Field Evaluation of the Stiffness of Unbound Aggregate Base Layers in Inverted Flexible
Pavements
85. Laboratory Performance Testing For The NCAT Pavement Test Track
86. Paved Shoulders Adjacent to Concrete Pavements: Synthesis of Current Practices in the
Midwest
87. Performance Analysis of Ultra-thin Whitetopping Intersections on US-169
88. Performance In Fatigue Cracking Of High Strength Concrete As Ultra-Thin Whitetopping
89. Performance of Flexible Pavement Maintenance Treatments in the LTPP SPS-3
Experiment
90. Physico-Chemical Characterization of Asphalt-Aggregate Interactions under the Influence
of Freeze-Thaw Cycles
91. Quantifying the Benefits of a Geocomposite Membrane as a Pavement Moisture Barrier
Using Ground Penetrating Radar and Falling Weight Deflectometer
92. Reinforcing Benefits of Geosynthetic Materials in Asphalt Concrete Overlays using Pseudo
Strain Damage Theory
93. A Simplified Overlay Design Model against Reflective Cracking Utilizing Service Life
Prediction
94. A Study On Properties Of Foamed Asphalt Treated Mixes
95. A Validated Model For Predicting Field Performance Of Aggregate Base Courses
96. Defining Asphalt Binder Fatigue as a Function of Pavement Temperature and
Pavement Structure
97. Variation Of Pavement Smoothness Between Adjacent Lanes: Implications For
Performance Based Contracting
Development of an Efficient Hot Mix Asphalt Fracture Mechanics-Based Crack Growth
Simulator
Boonchai Sangpetngam
Graduate Research Assistant
Department of Civil Engineering, University of Florida
345 Weil Hall, P. O. Box 116580
Gainesville, FL 32611-6580
Tel: (352) 392-9537
Fax: (352) 392-3394
Email: bsang@ufl.edu
Bjorn Birgisson
(Corresponding Author)
Assistant Professor
Department of Civil and Coastal Engineering
University of Florida, 345 Weil Hall, P. O. Box 116580
Gainesville, FL 32611-6580
Tel: (352) 392-9537
Fax: (352) 392-3394
Email: bbirg@ce.ufl.edu
Reynaldo Roque
Professor
Department of Civil Engineering, University of Florida
345 Weil Hall, P. O. Box 116580
Gainesville, FL 32611-6580
Tel: (352) 392-9537 ext. 1458
Fax: (352) 392-3394
ABSTRACT
It has long been accepted that cracking of hot-mix asphalt (HMA) pavements is a major mode of
premature failure. Many state agencies have verified that pavement cracking not only occurred in
fatigue cracking in which a crack initiates from the bottom of the asphalt layer but also in other
modes such as low temperature cracking, and the more recently identified top-down cracking.
Recent work at the University of Florida has led to the development of a viscoelastic fracture
mechanics-based crack growth law that is capable of fully describing both initiation and
propagation of cracks in asphalt mixtures. The model requires the determination of only four
fundamental mixture parameters that can be obtained from less than one hour of testing using the
-damage,
crack propagation, and healing for stated loading conditions, temperatures, and rest periods. This
paper describes the generalization of the hot mix asphalt crack growth law needed for the
successful implementation of the crack growth law into a displacement discontinuity boundary
element method. The resulting hot mix asphalt boundary element approach is shown to predict
the crack propagation of two coarse-graded mixtures under cyclic IDT loading conditions.
Keywords: pavement cracking, viscoelastic behavior, hot mix asphalt, numerical method,
displacement discontinuity method.
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An Updated Review Of SMA And Superpave Projects
Donald E. Watson, P. E.
National Center for Asphalt Technology
277 Technology Parkway
Auburn, AL 36830
Phone: (334) 844-6228
Fax: (334) 844-6248
E-Mail: dwatson@eng.auburn.edu
ABSTRACT
Stone Matrix Asphalt (SMA) and Superpave have represented relatively new mix design
technologies in this country. Therefore, a condition survey was conducted of mixes that had been
in service for several years in order to evaluate long-term performance of SMA and Superpave
projects. This is a follow-up study to a 1995 review of SMA projects and a 1998 review of
Superpave projects. Both SMA and Superpave are acknowledged to be rut-resistant mixes and
this was shown to be true during this project review. However, a significant amount of cracking
occurred early in the life of some of these mixtures. Overall, the SMA mixtures appeared to be
more durable than the Superpave mixtures evaluated. The SMA mixtures have been in place
about two and one-half years longer than the Superpave mixtures, but the overall condition is
about the same. Some of the primary conclusions from the survey are as follows: 1. Both SMA
and Superpave mixtures have been shown to be rut-resistant even when placed on high traffic
volume facilities. 2. Much of the observed cracking, especially load cracking, appeared to be
more related to problems other than mix design or material properties. 3. SMA mixtures can be
expected to last longer than Superpave mixtures before reaching the same condition level.
Key Words: Stone Matrix Asphalt, Superpave, rutting, cracking
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Analysis Of Permeability And Fluid Flow In Asphalt Mixes
Eyad Masad1, Bjorn Birgisson2, Aslam Al-Omari3, and Allen Cooley4
1 Assistant Professor
Department of Civil and Environmental Engineering
Washington State University
Pullman, WA 99164-99164
Tel.: (509) 335 9147
Fax: (509) 335 7632
Email: masad@wsu.edu
2 Assistant Professor
Department of Civil and Coastal Engineering
University of Florida
Gainesville, FL 32611
Tel.: (352) 392 9537
Fax: (352) 392 3394
Email: bbirg@ce.ufl.edu
3 Graduate Research Assistant
Department of Civil and Environmental Engineering
Washington State University
Pullman, WA 99164-99164
Tel.: (509) 335 0994
Fax: (509) 335 7632
Email: aslam@wsunix.wsu.edu
4 Manager
Southeastern Superpave Center
National Center for Asphalt Technology
277 Technology Parkway
Auburn, AL 36830
Tel.: (334) 844 6248
Fax: (334) 844 6228
Email: coolela@eng.auburn.edu
ABSTRACT
Permeability is an important property that influences the performance of hot mix asphalt
(HMA). It is a function of compaction effort, and several properties of HMA such as asphalt
content, and shape and size distribution of aggregates. Due to the different laboratory and field
methods for measuring permeability, and the interaction among the factors that influence
its value, it would be difficult to develop an analytical equation that accurately relates
permeability to all factors contributing to HMA permeability. This paper presents a simple
equation for approximating the permeability of asphalt mixes. It utilizes the percent air voids
and surface area of aggregates. The equation is empirical but it is derived based n the wellknown Kozeny-Carman equation or calculating the permeability of granular materials. The
developed equation was used successfully to fit permeability data collected from several studies
that carried field and laboratory measurements of HMA permeability. A finite element model
was developed to investigate the influence of the gradient of percent air voids in HMA on water
flow patterns. The X-ray computed tomography was used to measure the percent air void
gradients between sublayers of the asphalt mix. The permeability of these sublayers was
calculated using the developed equation, and used as an input to the finite element model.
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Economic Impact of Refining The Dynamic Internal Angle Of The Superpave® Gyratory
Compactor
Dr. George K. Chang, P.E.
Project Manager
The Transtec Group, Inc., 1012 East 38 ½ Street, Austin, Texas 78751
Phone: (512) 451-6233, Fax: (512) 451-6234
gkchang@thetranstecgroup.com
Dr. Robert Otto Rasmussen, P.E.
Vice President and Chief Engineer
The Transtec Group, Inc., 1012 East 38 ½ Street, Austin, Texas 78751
Phone: (512) 451-6233, Fax: (512) 451-6234
robotto@thetranstecgroup.com
Mr. Thomas Harman, P.E.
Asphalt Pavement Team Leader
Federal Highway Administration
Turner-Fairbank Highway Research Center
6300 Georgetown Pike, HDRI-11, McLean, Virginia 22101-2296
Phone: (202) 493-3072
Tom.Harman@fhwa.dot.gov
ABSTRACT
The purpose of the paper is to present qualitative as well quantitative comparisons of hot mix
asphalt pavement performance designed on Superpave® gyratory compactors with different
dynamic internal angles. The Superpave® gyratory compactor became the standard compaction
instrument for HMA design in the mid-1990’s with the national adoption of the Superpave®
system. Differences in compacted mixtures using Superpave® gyratory compactors from various
manufacturers have become a concern of State agencies and suppliers in the asphalt industry.
Through the analysis in this paper, the economic impact due to changes in the dynamic internal
angles of Superpave® gyratory compactors has been shown to be significant. It has been
determined that an increase in the DIA of 0.06°, from the target dynamic internal angle, results in
a national increase in the life-cycle cost by as much as $2 billion annually. This economic impact
justifies the need for a robust procedure to adjust and maintain dynamic internal angles of
Superpave® gyratory compactors using the Federal Highway Administration Dynamic Angle
Validator.
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Evaluation of Permeability of Superpave Asphalt Mixtures
Louay N. Mohammad1
Corresponding Author, Associate Professor, Louisiana Transportation Research Center and Dept. of Civil
and Environmental Engineering, Louisiana State University, Baton Rouge, LA 70803
Email: louaym@lsu.edu, Tel: 225-767-9126
Ananda Herath2,
2 Postdoctoral
Researcher, Louisiana Transportation Research Center
4101 Gourrier Ave., Baton Rouge, LA 70808
Email: mherath@lsu.edu, Tel: 225-767-9128
Baoshan Huang3
3 Assistant
Professor, Dept. of Civil and Environmental Engineering,
University of Tennessee, Knoxville, TN 37996
Email: bhuang@utk.edu, Tel: 865-974-7713
ABSTRACT
The presence of water in a pavement system is detrimental to its life. Permeable asphalt concrete
pavement structures are vulnerable to stripping causing premature damage under heavy traffic. In
order to assess the permeability of asphalt mixtures, a research study was conducted at the
Louisiana Transportation Research Center (LTRC). Laboratory permeability tests were
performed on field cores taken from seventeen Superpave projects in Louisiana. An LTRC
modified version of Karol-Warner’s falling-head permeameter was used to conduct the
permeability test. A sensitivity analysis was performed to relate the permeability test results to
the mixture volumetric properties such as the air void content, compaction effort, mixture
gradation, and lift thickness. A statistical regression model was developed to predict the
permeability of Superpave mixtures from the mixture volumetric properties. The model
successfully predicted the coefficient of permeability of asphalt mixtures from a separate data set
that was not included in the model development.
Keywords: Hot-mix asphalt concrete mixtures, Hydraulic conductivity, Permeability,
Superpave
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An Examination of Gamma Ray Methods for Measuring Bulk Specific Gravity of Hot-Mix
Asphalt Concrete
Kevin D. Hall, Professor
University of Arkansas
Department of Civil Engineering
4190 Bell Engineering Center
Fayetteville, AR 72701
kdh3@engr.uark.edu
(501) 575-8695
(501) 575-7168 Fax
Stacy G. Williams, Research Assistant Professor
Department of Civil Engineering
University of Arkansas
700 Research Center Blvd.
Fayetteville, AR 72701
sgwill@uark.edu
479-575-2220
Frances T. Griffith, Director, CTTP
Department of Civil Engineering
University of Arkansas
700 Research Center Blvd.
Fayetteville, AR 72701
ftg@engr.uark.edu
479-575-4497
ABSTRACT
There has been much attention given to the determination of the bulk specific gravity (Gmb) of
compacted hot-mix asphalt (HMA) specimens. For relatively open-graded HMA mixtures such
as those produced by Superpave and stone-matrix asphalt (SMA) design methods, perceived
potential shortcomings in traditional tests methods may be pronounced. Recently, a new device
was introduced for measuring Gmb ,which features the use of gamma-ray technology. In order to
evaluate the efficacy of the device, a total of 221 compacted HMA specimens were tested using
three test methods: (1) saturated surface dry (AASHTO T-166); (2) vacuum sealing (Corelok);
and (3) gamma-ray technology (CoreReader). Each specimen was tested three times in each of
the three methods. The specimens represented field-sampled and lab-prepared mixtures, 12.5 mm
and 25 mm nominal maximum aggregate sizes, and a variety of aggregates typically used in
Arkansas. Test results indicated that statistically significant differences exist between mean
Gmb values generated by each of the three testing methods. In general, the vacuum sealing
method yielded the lowest Gmb values, followed (in order of low to high) by gamma ray and
SSD. Significant differences in the variability of test results were not observed between test
methods. In terms of ease of testing and testing variability, the CoreReader gamma-ray device
does not appear to offer significant advantages for determining the bulk specific gravity of
compacted HMA cores. Further, agencies wishing to replace or allow alternatives to traditional
SSD-based tests should consider the impact of test results on existing volumetric property
specifications.
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Investigation Of The Tender Zone In The Compaction Of Coarse-Graded Superpave Hot
Mix Asphalt (HMA) Mixes
M. Shane Buchanan, Ph. D., P. E.
Assistant Professor
Civil Engineering
Mississippi State University
235 Walker Engineering Building
Mississippi State, Mississippi 39762
Telephone: (662) 325-3838
Fax: (662) 325-7189
e-mail:shaneb@engr.msstate.edu
L. Allen Cooley
Research Engineer
National Center for Asphalt Technology
277 Technology Parkway
Auburn, Alabama 38630
Telephone: (334) 844-6228
Fax: (334) 844-6248
e-mail:coolela@eng.auburn.edu
ABSTRACT
Tender hot mix asphalt (HMA) mixes have been observed and experienced by paving contractors
for many years. However, during the field compaction of coarse-graded Superpave mixes, a
“tender zone”, not a true tender mix, is sometimes experienced. The tender zone is range of mix
compaction temperatures during which the mix exhibits instability during roller action. There
have been many possible causes of the tender zone presented including differences in lab and
production absorption, mix moisture, low dust to asphalt ratio, increased asphalt binder film
thickness, and a temperature differential with the lift. A study was conducted to document and
evaluate field mixes exhibiting the tender zone to determine the possible cause(s) for its
occurrence. Documentation included mix, production, and construction related items. Laboratory
evaluation consisted of mix gradation and volumetric testing along with Superpave asphalt
binder testing on the project asphalt binder before and after steam distillation. Project results
failed to clearly identify one particular reason for the tender zone occurrence. However, it is felt
that the tender zone was a result of field absorption being less than design and increased asphalt
binder film thickness acting in conjunction with an inherent temperature differential within the
lift.
KeyWords: Tender Zone, Superpave, Steam Distillation
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Use Of PMS Data For Performance Monitoring With Superpave As An Example
W.R. Hudson, Ph.D., P.E.
Senior Consultant
TRDI, Inc.
2602 Dellana Lane
Austin, Texas 78746
Office: 512/327-4200, Fax: 512/328-7246
rhudson@trdi.com
C.L. Monismith
Professor
University of California at Berkeley
Department of Civil Engineering
Room 115, McLaughlin Hall
Berkeley, CA 94720
Office: 510/231-9587, Fax: 510231-9589
clm@newton.Berkeley.EDU
C.E. Dougan, Ph.D.
Senior Research Associate
University of Connecticut
Connecticut Transportation Institute
179 Middle Turnpike, U-202
Storrs, CT 06269-5202
Office: 860/486-5535, Fax: 860/486-2399
cdougan@engr.uconn.edu
W. Visser
TRDI, Inc.
2602 Dellana Lane
Austin, Texas 78746
Office: 512/327-4200, Fax: 512/328-7246
pvisser@trdi.com
ABSTRACT
The objective of this project was to examine how pavement management and related data in
various state DOTs can be used to evaluate the performance of new materials and to validate new
design concepts. Evaluating the performance of Superpave was used as an ideal example to
demonstrate the potential. No performance analyses are presented to date. The project started
with fact finding visits to the DOTs of Maryland, Florida, Indiana, Arizona and Washington.
Based on these findings the authors were asked to coordinate a Pathfinder study in Maryland,
where all required data from seven Superpave projects were collected and transferred to an
electronic file, and subsequently entered into a web-based system, developed by the University
of Washington, where the data could be analyzed. The project results show that it is possible for
state DOTs to assemble a database that can be used to evaluate the performance of Superpave
and other design and new materials concepts. The project was not large or long enough to make a
complete evaluation, but it did determine the feasibility of the concept and its applicability
among five states.
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Workability Of Hot Mix Asphalt
Jagan M Gudimettla
Graduate Research Assistant
National Center for Asphalt Technology
277 Technology Parkway
Auburn, AL 36830
Phone: (334) 332-0560
Fax: (334) 844-6248
Email: gudimettla@hotmail.com
L. Allen Cooley, Jr (Corresponding Author)
Manager, Southeastern Superpave Center
National Center for Asphalt Technology
277 Technology Parkway
Auburn, AL 36830
Phone: (334) 844-6228
Fax: (334) 844-6248
Email: coolela@eng.auburn.edu
ABSTRACT
Workability of Hot Mix Asphalt (HMA) is a critical element in getting the desired density of
bituminous pavements. Density is in turn responsible for long lasting and better performing
pavements. Temperature as well as the constituents in the mix influence workability of Hot Mix
Asphalt. Due to the increased use of modified binders and mixes with high level of filler content,
both of which increase the viscosity of the binder, the workability of HMA mixes has become
more important issue. Based on previous instruments used to measure workability, in concrete
and HMA industry a new device was developed to measure workability of HMA. Workability of
with mixes with expected range of workabilities. Once the machine was able to distinguish the
different mixes based on workability it was tested with mixes with different combinations of
nominal maximum aggregate size (12.5 mm and 19mm), gradation shape (fine- and coarsegraded), aggregate type (granite, limestone, and crushed gravel) and binder type (PG 64-22, PG
70-22 and PG 76-22) on workability. The effects of each of the individual constituents and
temperature on the mix workability were analyzed. The device developed was able to
differentiate mix workability based on the constituents of the mix.
KeyWords: Workability, compactability, mixing and compaction temperatures, gradation
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The Effect of Volumetric Properties on Mechanical Behavior of Asphalt Mixtures
Terhi K. Pellinen
School of Civil Engineering
Purdue University
1284 Civil Engineering Building
West Lafayette, IN 47907-1284
ABSTRACT
The empirical nature of mix design method development has led to significant differences in the
volumetric composition for an acceptable asphalt mix. A key to the successful mix design is the
balance between the volumetric composition and the used raw materials (binder, aggregate,
filler, and additives) at specific climatic and traffic conditions. Thus, a balanced design can be
achieved only when the climatic considerations are taken in account when selecting the
volumetric criteria. A delicate balance between mixture stiffness and shear strength appears to
provide the key to a successful design. Based on these findings, a fundamentally based
conceptual performance criteria is presented; the criteria rely on stiffness and shear strength to
explain the mechanical behavior of asphalt mixtures.
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Georgia DOT’s Evaluation of a Remixing Paver
Georgene M. Geary, P.E.
State Materials & Research Engineer
georgene.geary@dot.state.ga.us
Peter Y. Wu, Ph.D., P.E.
State Bituminous Construction Engineer
peter.wu@dot.state.ga.us
Sheila Hines
Bituminous Technical Services Manager
sheila.hines@dot.state.ga.us
David Jared, E.I.T.
Special Research Engineer
david.jared@dot.state.ga.us
Georgia Department of Transportation
15 Kennedy Drive
Forest Park, Georgia 30297-2599
Phone: (404) 363-7500
Fax: (404) 363-7684
ABSTRACT
Georgia DOT (GDOT) evaluated a remixing paver to determine its ability to meet GDOT
specifications concerning gradation- and temperature segregation on asphalt paving projects. In
the remixing paver, augers are used to control the movement of asphalt from the hopper to the
screed, rather than the slat conveyors used in conventional pavers. Two projects in Carroll
County, Georgia were selected for the evaluation, and the general scope of the evaluation was
the same for both projects. In order to monitor gradation segregation, a select number of asphalt
loads were produced at the asphalt plant in a manner that would foster segregation. Special
GDOT and private lab asphalt samples were taken at the plant and on the roadway from the
contractor acceptance samples and from the intentionally segregated mix. Roadway density
readings were taken to evaluate the uniformity of the plant mix density after placement, and
hence monitor gradation segregation. Temperature segregation was monitored via photos from
an infrared camera. Based on the results obtained, the degree of remixing provided by the
remixing paver for the mixes under consideration was generally insufficient to satisfy GDOT
requirements for gradation- and temperature segregation. Segregation problems were observed
when the mix was purposely segregated and when it was not. Indications of remixing were
evidenced in the evaluation but not consistently enough to satisfy GDOT requirements.
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An Investigation Of Factors Influencing Permeability Of Superpave Mixes
Mohd Rosli Hainin (Corresponding Author)
Graduate Research Assistant
National Center for Asphalt Technology
277 Technology Parkway
Auburn, AL 36830
Phone: (334) 844-6228
Fax: (334) 844-6248
Email: hainimr@eng.auburn.edu
L. Allen Cooley, Jr.
Manager, Southeastern Superpave Center
National Center for Asphalt Technology
277 Technology Parkway
Auburn, AL 36830
Phone: (334) 844-6228
Fax: (334) 844-6248
Email: coolela@eng.auburn.edu
Brian D. Prowell
Assistant Director
National Center for Asphalt Technology
277 Technology Parkway
Auburn, AL 36830
Phone: (334) 844-6228
Fax: (334) 844-6248
Email: Bprowell@eng.auburn.edu
ABSTRACT
Permeability has become a continuing issue discussed in the hot mix asphalt (HMA) community,
especially with the introduction of Superpave mixes in late 1990s. Permeability can cause an
increased potential for oxidation, raveling, cracking, and water damage in HMA pavements. The
objective of this study is to evaluate the permeability characteristics of Superpave pavements and
determine the influence of in-place density, nominal maximum aggregate size (NMAS),
gradation, lift-thickness, and design compactive effort (Ndes) on the permeability of these
pavements. A total of 354 cores were obtained from 42 different Superpave projects immediately
after paving. Five different mix types utilized in this study were fine-graded 9.5 mm, 12.5 mm,
and 19.0 mm NMAS mixes and coarse-graded 9.5 mm and 12.5 NMAS mixes. Bulk specific
gravity of cores was determined using AASHTO T 166 and a vacuum sealing method (Corelok).
The permeability test was performed according to ASTM PS129-01. The results of the
investigation indicate that in-place void content is the most significant factor impacting
permeability of Superpave pavements. Air voids determined using vacuum sealing method
(Corelok) has more impact on permeability than AASHTO T 166 method. This is followed by
coarse aggregate ratio, percent passing 12.5 mm sieve, percent passing 1.18 mm sieve, Ndes, and,
lift thickness. As the values of coarse aggregate ratio, percent passing 12.5 and 1.18 mm sieve,
and Ndes increase, permeability increases. For coarse-graded mixes, as the coarse aggregate ratio
approaches 1.0 or higher, permeability increases significantly. Permeability decreases as lift
thickness increases.
Back to Table of Contents
Laboratory Evaluation Of The Effect Of SBS Modifier On Cracking Resistance Of Asphalt
Mixture
Booil Kim, Graduate Research Assistant
Department of Civil Engineering
University of Florida
P. O. Box 116580
Gainesville, FL 32611-6580
Tel: (352) 846-3427
Fax: (352) 392-1660
Email: bikim@ufl.edu
Reynaldo Roque, Professor
(Corresponding Author)
Department of Civil Engineering
University of Florida
P. O. Box 116580
Gainesville, FL 32611-6580
Tel: (352) 392-9537 (1458)
Fax: (352) 392-1660
Email: rroqu@ce.ufl.edu
Bjorn Birgisson, Assistant Professor
Department of Civil Engineering
University of Florida
P. O. Box 116580
Gainesville, FL 32611-6580
Tel: (352) 392-9537 (1462)
Fax: (352) 392-1660
Email: bbirg@ce.ufl.edu
ABSTRACT
A laboratory investigation was conducted to evaluate the effects of SBS modification on the
cracking resistance and healing characteristics of coarse-graded Superpave mixtures. Four types
of asphalt mixtures with 6.1% and 7.2% design asphalt contents using unmodified and SBS
modified asphalt cement were produced in the laboratory. Tests performed with the Superpave
IDT included repeated load fracture test, healing test, strength tests at two loading rates, as well
as longer-term creep tests to failure. The test results showed that the benefit of SBS modifiers to
mixture cracking resistance appeared to be primarily derived from a reduced rate of microdamage accumulation. The reduced rate of damage accumulation was reflected in a lower
mvalue without a reduction in fracture energy limit or healing rates. It was shown that the
benefits of the SBS modifier were clearly identified by using the HMA fracture model, which
accounts for the combined effects of m-value and fracture energy limit on cracking resistance. It
was also determined that the residual dissipated energy as determined from Superpave IDT
strength tests appears to be uniquely associated with the presence and benefit of SBS
modification, and may provide a quick way to make relative comparisons of cracking
performance suitable for SBS-modified mixtures. Longer-term creep test results showed that
time to crack initiation appeared to provide another parameter uniquely related to the effects of
SBS modification. In conclusion, the key to characterizing the effects of SBS modifier on the
cracking resistance of asphalt mixture is in the evaluation of the combined effects of creep and
failure limits.
Back to Table of Contents
Interlayer and Design Considerations to Retard Reflective Cracking
Phil Blankenship Natalie Iker
Koch Pavement Solutions
4900 S. Mason Ave
Chicago, IL 60638
phone: 316/828-8495 phone: 708/594-4148
fax: 316/828-7385 fax: 708/458-1564
blankenp@kochind.com ikern@kochind.com
Joseph Drbohlav
Koch Pavement Solutions
4027 E. 37th St. North
Wichita, KS 67220
phone: 316/828-7748
fax: 316/828-7385
drbohlaj@kochind.com
ABSTRACT
To protect the structure and provide a new, smoother riding surface, many highway agencies
overlay deteriorating Portland cement concrete pavements with hot mix asphalt (HMA) overlays.
Reflective cracking through the overlays has been a persistent problem. Most methods used to
delay the cracks have been based on tension, or the horizontal movement occurring at the crack
or joint interface. A performance-related flexural fatigue test addresses the tension, shear and
bending forces that result in the reflective cracks. A reflective crack relief system consisting of
an impermeable, highly elastic interlayer using fine graded aggregates and a quality hot mix
asphalt overlay has been specified using the flexural fatigue for crack resistance and Hveem
stability for rutting resistance. Preliminary cracking data from several projects placed using the
specification and their control sections shows that the reflective cracking is delayed. Cores taken
from the test sections show that even when the overlay cracks, the interlayer remains intact and
impermeable, protecting the pavement structure from moisture intrusion. These cores also show
that, unlike the control sections, the reflective cracks over the new system are offset from the
underlying joints, further disrupting paths for water and giving better rideability. Seven state
departments of transportation have used the performance-related specification for constructing
the interlayer and overlay.
Back to Table of Contents
Precision of Shear Tests Used for Evaluating Asphalt Mixtures
R. Michael Anderson*
Asphalt Institute
P.O. Box 14052
Lexington, KY 40512-4052
859.288.4984 (voice)
859.288.4999 (FAX)
manderson@asphaltinstitute.org
Gerald A. Huber
Heritage Research Group
7901 West Morris Street
Indianapolis, IN 46231
317.390.3141 (voice)
317.486.2985 (FAX)
Gerald.Huber@heritage-enviro.com
Richard K. Steger
Koch Performance Roads, Inc.
P.O. Box 1875
Wichita, KS 67201
316.828.3081 (voice)
316.529.7696 (FAX)
stegerr@kochind.com
Pedro Romero
University of Utah
Dept. of Civil & Environmental Engineering
122 South Central Campus Drive
EMRO Bld. Ste. 104
Salt Lake City, UT 84112-0561
801.587.7725 (voice)
801.585.5477 (FAX)
romero@civil.utah.edu
ABSTRACT
Various methods exist to measure the mechanical properties of Hot Mix Asphalt (HMA). To be
useful such a test must not only measure a property that controls performance, but the test must
be repeatable. The Strategic Highway Research Program developed tests using the Superpave
Shear Tester (SST) which have been shown to be related to HMA performance. To date
repeatability has not been quantified. This paper reports the results of a repeatability study for the
measurement of shear stiffness (frequency sweep) and the measurement of permanent shear
strain (repeated-load, constant-height testing).
Key words: Hot Mix Asphalt, Superpave, Superpave Shear Tester, shear stiffness, permanent
shear strain, repeatability
Back to Table of Contents
Superpave Laboratory Compaction Versus Field Compaction
Robert L. Peterson
Asphalt Materials Engineer
Asphalt Institute
Lexington, KY 40512
859-288-4977
bpeterson@asphaltinstitute.org
Kamyar C. Mahboub, Ph.D., P.E. (Contact Person)
Associate Professor of Civil Engineering
University of Kentucky, Lexington, KY 40506-0281
859-257-4279
kmahboub@engr.uky.edu
R. Michael Anderson, P.E.
Director of Research
Asphalt Institute
Lexington, KY 40512
859-288-4984
manderson@asphaltinstitute.org
Eyad Masad, Ph.D.
Assistant Professor of Civil Engineering
Washington State University
Pullman, WA 91964-2910
509-335-9147
Laith Tashman
Graduate Research Assistant
Washington State University
Pullman, WA 91964-2910
509-335-0994
ABSTRACT
Laboratory compaction is an important part of asphalt mix design. In order for the mix design
process to be effective, laboratory compaction must adequately simulate field compaction. This
study used mechanical properties measured with the Superpave Shear Tester to evaluate field
compaction and laboratory compaction. The field compaction consisted of three test sections
with different compaction patterns. The laboratory compaction used the Superpave Gyratory
Compactor with adjustments to several parameters. Results of this study indicate that current
gyratory protocol produces specimens with significantly different mechanical properties than
field cores produced with the same material and compacted to the same air voids. Results also
show that adjustments to certain parameters of the gyratory can produce specimens that better
simulate the mechanical properties of pavement cores.
KEYWORDS: Superpave Gyratory Compactor, Air Voids, Mechanical Properties, Asphalt,
Pavement Cores.
Back to Table of Contents
Application of Infrared Imaging and Ground-Penetrating Radar for Detecting Segregation
in Hot-Mix Asphalt Overlays
Stephen Sebesta
Assistant Transportation Researcher
Texas Transportation Institute
Texas A&M University
Room 501 CE/TTI Tower
College Station, TX 77843-3135
Phone: (979) 845-5845
Fax: (979) 845-1701
s-sebesta@tamu.edu
Tom Scullion, P.E.
Research Engineer
Texas Transportation Institute
Texas A&M University
Room 501 CE/TTI Tower
College Station, TX 77843-3135
Phone: (979) 845-9910
Fax: (979) 845-1701
t-scullion@tamu.edu
ABSTRACT
Segregation is a serious problem in hot-mix asphalt and typically results in poor performance,
poor durability, shorter life, and higher maintenance costs of the pavement. This paper presents a
summary of results and recommendations from three projects in Texas in which infrared imaging
and ground-penetrating radar were used to examine the uniformity of the pavement mat. Both
techniques have significant advantages over currently used nuclear density techniques in that
they provide virtually 100 percent coverage of the new surface. The effectiveness of both the
infrared and radar techniques was evaluated by taking measurements on new overlays at the time
of placement, coring, then identifying relationships between changes in the infrared and radar
data with changes in the measured volumetric and engineering properties of cores. Analyses of
results showed that changes in both infrared and radar data are significantly related to changes in
hot-mix asphalt properties such as air void content and gradation. Based upon current Texas
Department of Transportation specifications, significant changes in the hotmix asphalt are
expected if temperature differentials of greater than 25 oF (13.9 oC) are measured after
placement but before rolling. If the surface dielectric of the in-place mat changes by more than
0.8 for coarse-graded mixes and 0.4 for dense-graded materials, significant changes in mix
properties are expected. Given the promising results from this work, agencies should consider
implementing both the infrared and ground-penetrating radar technologies.
Back to Table of Contents
Case Study: Preliminary Field Validation of Simple Performance Tests for Permanent
Deformation
Fujie Zhou
Research Associate, Texas Transportation Institute
501F CE/TTI Building, Texas A&M University, College Station, TX 77843
Phone: 979-458-3965, Fax: 979-845-1701, Email: f-zhou@tamu.edu
Tom Scullion
Research Engineer, Texas Transportation Institute
501E CE/TTI Building, Texas A&M University, College Station, TX 77843
Phone: 979-845-9913, Fax: 979-845-1701, Email: t-scullion@tamu.edu
ABSTRACT
“Simple Performance Test” (SPT) to be used with the Superpave volumetric mixture design
procedure has recently been recommended by National Cooperation Highway Research Program
(NCHRP) Superpave Project 9-19 (“Simple Performance Test for Superpave Mix Design). The
field validation of SPT is critically important to its final acceptance and implementation in dayto-day Superpave mixture design practice. The Special Pavement Studies-1 (SPS-1) premature
rutted sections on US281, Texas, were used to validate SPT for permanent deformation,
including dynamic modulus test, repeated load test, and associated rutting indicators,
n), respectively. The results of this case study clearly show that
n can effectively
distinguish the good mixtures from the bad. It preliminarily validated both Simple Performance
Tests for permanent deformation. In addition, this paper also clarifies the location of tertiary
point in the permanent strain vs. load repetitions plot; and a simple linear model needs to be
added in order to determine the Flow Number. Furthermore, this paper discusses the possibility
of using the number of load repetitions (Nps) corresponding to the initial point of the secondary
stage to characterize the rutting resistance of asphalt mixtures, which is supported by the limited
data presented in this paper. This indicator is supported by the limited data presented in this
paper, and it can be easily determined and reduce significantly the test duration.
KEYWORDS: Simple Performance Test, Permanent Deformation, Dynamic Modulus, Flow
Number
Back to Table of Contents
Establishing the Superpave Ndesign Compaction Matrix Using Information Collected in
Northern Taiwan Area
Jyh-Dong Lin
Professor
National Central University, Department of Civil Engineering
No.300, Jung-da Rd., Jung-li City, Taoyuan, Taiwan 32054, R.O.C
Tel: (886-3) 4227151-4123, Fax: (886-3) 422-7183, jyhdongl@cc.ncu.edu.tw
Shih-Huang Chen*
Ph.D. Candidate Student
National Central University, Department of Civil Engineering
No.300, Jung-da Rd., Jung-li City, Taoyuan, Taiwan 32054, R.O.C
Tel: (886-3) 4227151-4087, Fax: (886-3) 422-7183, s8342008@cc.ncu.edu.tw
Pei Liu
Assistant professor
Feng-Chia University
No.100 Wen-Hwa Rd, TaiChung, 407 Taiwan , R.O.C
Tel: (886-4) 424524362, peiliu@fcu.edu.tw
Shu-Hao Lin
Assistant Professor
Sze-Hai Institute of Technology and Commerce
No.1, Lane 380, Tu-Cheng City Taipei County, Ching-Yun Rd, Taiwan, R.O.C
Tel: (886-9) 21160082, shlin@sitc.edu.tw
ABSTRACT
The Superpave design specification provides an Ndesign compaction matrix for compaction of
asphalt concrete mixture. In the matrix, compaction effort parameters for use under various
traffic levels were specified. Since traffic characteristics and materials available in Taiwan are
different from those in the States, it is worthwhile to evaluate the applicability of the Ndesign
compaction matrix in Taiwan.
General pavement studies on nine test sites in northern Taiwan were performed. Samples were
cored, and increases of %Gmm of all test sites were calculated. By assuming the degree of
compaction at the time of opening was the same for all sites, %Gmm of cored samples were
adjusted in accordance to this assumption. Aggregates recovered from each test site were then
remixed according to the original job mix formula, aged, and SGC compacted. Traffic
characteristics of each test site were obtained from project installed WIMs, and weighted
averages of available data in vicinity areas as well. Meanwhile, traffic volumes were collected
and estimated from officially surveyed data. Accumulated ESALs of each test site during studied
period was then calculated. Correlations of information obtained from the above procedures
were performed. It was observed that derived correlations between Nini, Nmax and Ndes are
slightly different (differences of respective coefficients are with 10%) from those specified by
SHRP. Nonetheless, the gyration efforts specified in the Superpave Ndesign compaction matrix
seem too low for situations in Taiwan. High volumes of overloaded trucks may be the reason for
high SGC gyrations. More studies on this issue are needed to verify such phenomenon.
Keyword: Superpave Gyratory Compressor (SGC), Compaction, ESAL, and WIM
Back to Table of Contents
New Mix-Design Procedure of Cold In-Place Recycling for Pavement Rehabilitation
K. Wayne Lee, Ph.D., P.E.
Professor of Civil Engineering and
R&D Director of Transportation Center
University of Rhode Island
Tel: (401) 874-2695 Fax: (401) 874-2297
e-mail: lee@egr.uri.edu
Todd E. Brayton
Bryant Associates, Inc.
12 Breakneck Hill Road
Lincoln, RI 02865
Tel: (401) 722-7660 Fax: (401) 722-7530
e-mail: Tbrayton@bryant-engrs.com
Jason Harrington
Federal Highway Administration
Pavement Division
400 Seventh Street, S.W.
Washington, D.C. 20590
Tel: (202) 366-1576 Fax: (202) 366-9981
e-mail: K.Jason.Harrington@fhwa.dot.gov
ABSTRACT
An attempt has been made to develop a new mix-design method for use with the Cold In-Place
Recycling (CIR) of asphalt pavement with the assistance from the Federal Highway
Administration (FHWA). Evaluation results of the modified Marshall Design method from the
AASHTO Task Force No. 38 have suggested that it is not the future for CIR mixtures.
Expanding use of the Superpave technology deems it vitally necessary to provide a mix-design
procedure for CIR that for the hot mix asphalt (HMA) with modifications for the nature of cold
mixes. Thus, a new volumetric mix-design utilizing the Superpave gyratory compactor (SGC)
has been developed for use with CIR materials. It was primarily developed for partial-depth
CIR, using emulsion as the recycling additive. The new mix-design procedure was evaluated
using materials from five geographically varied locations in North America. The present study
has recommended further development of a procedure to evaluate the performance of CIR
mixtures that have been prepared in accordance with the new procedure. Since the Superpave
performance analysis procedure for HMA has not been finalized, only the creep compliance and
indirect tensile strength tests were performed to evaluate the low temperature cracking
characteristics of CIR mixtures. A test section has been established in Arizona with CIR
mixtures using the new mix design procedure in October 2000, and is performing well with no
visible cracking or distresses.
Back to Table of Contents
Performance Evaluation Of Polymer Modified Superpave Mixes Using Laboratory Tests
And Accelerated Pavement Load Facility
SANG-SOO KIM (Corresponding Author)
Assistant Professor
SHAD M. SARGAND
Professor
Department of Civil Engineering
Ohio University
Athens, OH 45701
Tel: 740-593-1463
Fax: 740-593-0625
E-mail: skim@bobcat.ent.ohiou.edu
ABSTRACT
Effects of polymer modification and aggregate gradation on rutting and fatigue resistance of
Superpave mixes were evaluated using laboratory tests and an indoor load facility test. Asphalt
mixes were prepared using three different PG 70-22 binders (unmodified, SBS and SBR
modified), and were evaluated using a triaxial repeated load test, a static creep test, the Asphalt
Pavement Analyzer test, and the flexural beam fatigue test. The rut resistance was also evaluated
using the OU Accelerated Pavement Load Facility (APLF). When aggregates meeting Superpave
angularity requirements were used, the effects of gradation on the rut and fatigue resistance of
Superpave mixes were relatively small. Even though binders used in this study had similar
dynamic shear moduli, mixes containing polymer modified binders showed significantly lower
resilient moduli than the unmodified mixes when measured in the indirect tensile and Triaxial
compressive modes. All laboratory test results indicated that the polymer modified mixes were
significantly more rut resistant and fatigue resistant than the unmodified mixes with the same PG
grading. Improvement in rut resistance due to polymer modification was shown to be most
significant in the triaxial repeated load test, especially at a higher temperature. In summary, the
Superpave mixes were highly rut resistant and effects of gradation variation on rut and fatigue
resistance were small. The mixes with polymer modified binders were more rut and fatigue
resistant than the unmodified mixtures. The triaxial repeated load test showed much more
sensitivity to polymer modification than the uniaxial static creep test.
KEY WORDS: asphalt, pavement, Superpave, polymer, aggregate, gradation, performance
Back to Table of Contents
The Effects of HMA Mixture Characteristics on Rutting Susceptibility
Stacy G. Williams, Ph.D., P.E.
Research Assistant Professor
Department of Civil Engineering
University of Arkansas
700 Research Center Blvd., Rm. 213
Fayetteville, AR 72701
479-575-2220
479-575-7639 (FAX)
sgwill@uark.edu
ABSTRACT
Permanent deformation, or rutting, is a primary failure mode of hot-mix asphalt (HMA)
pavements. Many mixture characteristics are known to affect pavement rutting, though a
comprehensive relationship of such characteristics to rutting has proven to be quite elusive. This
project explores the relationships of HMA mixture properties to rutting susceptibility as
measured by the utilization of wheel-tracking devices. Two analyses involving regression
procedures were performed in an attempt to develop mathematical relationships between
laboratory measurements of rutting susceptibility and HMA mixture characteristics. The overall
conclusion of this analysis was that while many factors play a role in the rutting characteristics of
HMA samples, regression procedures were unable to determine valid mathematical relationships;
however, several important trends were documented. As VMA increases, so does rut depth. This
implies that higher VMA may not be desirable for the mixes involved in the analysis with respect
to rutting performance. As the PG binder grade increases, rut depths decrease. Binders are
polymer-modified with the intention of improved performance, which can translate to a decrease
in rutting susceptibility. As binder content increases so does rut depth. This is expected because
too much binder can actually lubricate the aggregate particles, allowing them to shift more than
they should. Finally, as film thickness increases, rut depth also increases. Too much film
thickness causes the aggregate to be more likely to move.
Back to Table of Contents
An Evaluation Of Use Of Rapid Triaxial Test In Quality Control Of Hot Mix Asphalt
(HMA)
Jonathan S. Gould
Undergraduate Research Assistant
Worcester Polytechnic Institute (WPI)
Phone: 508 831 6035, Fax: 508 831 5808, E-mail: gouldj@wpi.edu
Yamini V. Nanagiri
Graduate Research Assistant
Worcester Polytechnic Institute (WPI)
Phone: 508 831 5826, Fax: 508 831 5808, E-Mail: yamini@wpi.edu
Rajib B. Mallick (Corresponding Author)
Assistant Professor
Civil and Environmental Engineering Department
Worcester Polytechnic Institute (WPI)
100 Institute Road
Worcester, MA 01609
Phone: 508 831 5289, Fax: 508 831 5808, E-Mail: rajib@wpi.edu
Joseph D. Petruccelli
Professor, Mathematical Sciences
Worcester Polytechnic Institute (WPI)
100 Institute Road
Worcester, MA 01609
Phone: 508 831 5362, Fax: 508 831 5824, E-mail: jdp@wpi.edu
William C. Crockford
President, ShedWorks
Phone: 979 695 8416, Fax: 303 265 9359, E-mail: wwc@shedworks.com
ABSTRACT
The objectives of this research are to evaluate the rapid triaxial test method for use in quality
control of HMA production and if possible, determine test conditions for getting reliable results.
The scope of this study consisted of testing different mixes at two different temperatures and
frequencies and evaluating the results. The equipment is rugged and portable, and the hardware
and software are easy to handle and do not require extensive technician training. The results from
this study show that modulus and phase angle values obtained from testing are sensitive to key
mixture components and properties. The coefficients of variation of results obtained from tests
conducted at 60oC and 1 Hz are low. Tests with fine graded mixes showed good correlation of
dynamic stiffness parameters with rutting, and the stiffness parameters were found to be sensitive
to dust to effective binder ratio. One significant advantage of using this test procedure as a
regular quality control tool is that decisions can be taken on the basis of performance related
parameters rather than on the basis of volumetric properties only. Considering the desirable
qualities, it seems that this test method can be considered for regular use for quality control
testing. However, before it is used, user agencies must test mixes using an adopted test protocol,
and establish target values and allowable variations.
Key words: Rapid Triaxial Test, quality control, HMA
Back to Table of Contents
Field Evaluation of Asphalt Additives to Control Rutting and Cracking
Rebecca S. McDaniel
Technical Director
North Central Superpave Center
Purdue University
P. O. Box 2382
West Lafayette, IN 47906
765/463-2317; fax 765/497-2402
rsmcdani@purdue.edu
Hussain U. Bahia
Associate Professor
Department of Civil and Environmental Engineering
University of WI- Madison
2210 Engr. Hall, 1415 Engr. Dr
UW Madison, 53706
608/265-4481; fax 608/262-5199
hubahia@facstaff.wisc.edu
ABSTRACT
This paper presents the results of an investigation of the performance of a variety of materials
added to asphalt binders and mixtures to change their properties, particularly with respect to
rutting and cracking. Two approaches were taken. The first was a field trial of seven polymer and
particulate modifiers. The modifiers evaluated included Polymerized Asphalt Cement,
Novophalt, Multigrade Asphalt Cement, Polyester Fibers, Neoprene, SBR and Asphalt Rubber.
The second approach was a laboratory study of the effects of these modifiers on binder and
mixture properties. The field trial showed that different modifiers do yield different performance.
Modifiers are not essential to ensure that the pavement will not rut; none of the mixtures
evaluated here exhibited appreciable rutting. Dramatic differences were noted in the cracking
behavior, however. The newly developed MP-1a binder tests were able to identify binders that
would be more prone to cracking.
Back to Table of Contents
Measuring And Predicting Hydraulic Conductivity (Permeability) Of Compacted Asphalt
Mixtures In The Laboratory
Kunnawee Kanitpong
Hussain U. Bahia
Craig H. Benson
Xiaodong Wang
Department of Civil and Environmental Engineering
2210 Engineering Hall, 1415 Engineering Dr.
The University of Wisconsin-Madison, Madison, WI, 53706
kanitpon@cae.wisc.edu, bahia@engr.wisc.edu, benson@engr.wisc.edu,
wang1@cae.wisc.edu
ABSTRACT
Hydraulic conductivity of asphalt mixtures is known to be affected significantly by air void
content, but may also be affected by other factors such as specimen thickness, aggregate shape,
and aggregate gradation. This study was conducted to study the effect of these factors and
quantify them relative to effect of air voids. Extensive hydraulic conductivity testing of more
than 40 different types of asphalt mixtures was conducted and permeability prediction methods
recently proposed by others were used to estimate hydraulic conductivity. The results indicate
that air void content is the predominant factor controlling hydraulic conductivity, but aggregate
shape (source) and gradation also have a statistically significant influence. Specimen thickness
was not found to be a statistically significant factor affecting hydraulic conductivity of laboratory
prepared specimens. Although shape and gradation can be used as indicator variables to improve
the prediction of hydraulic conductivity statistically, there still exist appreciable differences
between predicted and measured hydraulic conductivities. In addition, the proposed protocol of
using effective air voids or surface porosity does not show promising results. It appears that the
lack of agreement between measured and predicted hydraulic conductivity is related to the
saturation of voids and the complexity of the void structure.
Key Words: hydraulic conductivity, permeability, asphalt, air voids, effective air voids, porosity
Back to Table of Contents
Micro-Deval Testing Of Aggregates In The Southeast
L. Allen Cooley, Jr.
Manager, Southeastern Superpave Center
National Center for Asphalt Technology
277 Technology Parkway
Auburn, AL 36830
Phone: 334-844-6228
Fax: 334-844-6248
Email: coolela@eng.auburn.edu
Robert S. James
National Center for Asphalt Technology
277 Technology Parkway
Auburn, AL 36830
Phone: 334-844-6228
Fax: 334-844-6248
Email: jamesro@eng.auburn.edu
ABSTRACT
Aggregate used in hot mix asphalt (HMA) must be tough and durable, not only to withstand the
effects of HMA production, transportation, and construction but also resist the effects of traffic
and the environment. Historically, the Los Angeles Abrasion and Impact test has determined the
toughness of aggregates. The long-term durability characteristics of aggregates are generally
determined using a soundness test: sodium or magnesium sulfate. During the National
Cooperative Highway Research Program’s Project 4-19, the Micro-Deval test, in conjunction
with the magnesium sulfate soundness test, were recommended in lieu of the Los Angeles
Abrasion and Impact test and other soundness tests. Therefore, a study was needed within the
Southeast U.S. to evaluate the range in Micro-Deval results that could be expected. The
objective of this research was to characterize the toughness/durability of aggregates with respect
to their Micro-Deval test results. Seventy-two aggregate sources from eight different states were
included in this research. These aggregates were rated as “good”, “fair”, or “poor” with respect
to performance by the contributing state. Based upon the results of this study, some large
differences were found in Micro-Deval test results within a given performance category. Within
a given performance category, significant differences were also found in Micro-Deval results
between different aggregate mineralogical types. Also, there was no relationship between Los
Angeles Abrasion and Impact and Micro-Deval test results.
Back to Table of Contents
Resilient Modulus, Tensile Strength, and Simple Shear Test to Evaluate Moisture
Sensitivity and the Performance of Lime in Hot Mix Asphalt Mixtures
Martin McCann, Ph.D., PE
Western Research Institute
365 North 9th Street
Laramie, WY 82072-3380
Phone: 307-721-2254
Fax: 307-721-2345
E-mail: mmccann@uwyo.edu
Dr. Peter E. Sebaaly
Professor – University of Nevada, Reno
Civil Engineering Dept. Mail Stop 258
Reno, NV 89557
Phone: 775-784-6565
Fax: 775-784-1429
E-mail: sebaaly@unr.nevada.edu
ABSTRACT
The use of hydrated lime in hot mix asphalt (HMA) is an accepted practice used by many state
highway departments. However, there are various techniques of introducing lime into the
mixture and several factors that favor one method over another. The goal of this study was to
evaluate the mechanical properties of lime-treated HMA mixtures before and after multiple
cycles of freeze-thaw moisture conditioning. The mechanical tests used were the resilient
modulus, tensile strength, and simple shear test. In addition, the study compared the three test
procedures for evaluating the moisture sensitivity of HMA mixtures. With the addition of lime
and after multiple cycles of freeze-thaw moisture conditioning, all mixtures demonstrated an
enhanced ability to retain the original measured properties. The four methods of lime treatment:
dry lime to moist aggregates, lime slurry to dry aggregates, and each application method
receiving either a 48 hour marination time or no marination time, were found to be statistically
equivalent. The evaluation of moisture sensitivity of a HMA mixture is possible with all three
mechanical test procedures. Resilient modulus proved to be the best technique for measuring
small reductions in strength. When the loss of strength due to moisture sensitivity exceeded 20
percent, the measurement of tensile strength provided a better statistical correlation.
Back to Table of Contents
Simulation of Fracture Initiation in Hot Mix Asphalt Mixtures
Chote Soranakom
Graduate Research Assistant
Department of Civil & Coastal Engineering, University of Florida
P.O. Box 116580, Gainesville, FL 32611-6580,
Tel (352) 392-9537 ext 1468, E-mail: mrchote@yahoo.com
Bjorn Birgisson
(Corresponding Author)
Assistant Professor
Department of Civil & Coastal Engineering, University of Florida
P.O. Box 116580, Gainesville, FL 32611-6580,
Tel: (352) 392-9537 ext 1462, E-mail: bbirg@ce.ufl.edu
John A.L. Napier
CSIR Fellow
Council for Scientific and Industrial Research, Miningtek Division
Johannesburg, South Africa
Email: jnapier@csir.co.za
Reynaldo Roque
Professor
Department of Civil & Coastal Engineering, University of Florida
P.O. Box 116580, Gainesville, FL 32611-6580,
Tel: (352) 392-9537 ext 1458, Email: rroqu@ce.ufl.edu
ABSTRACT
This paper presents a displacement discontinuity boundary element method to explicitly model
the microstructure of asphalt mixtures and to predict their tensile strength and fracture energy
density. The loading response of three mixtures was simulated to assess the mechanics of
fracture in the Superpave indirect tension test. The predicted tensile strength and fracture energy
density of three samples were comparable to their test results. The predicted crack initiation and
crack propagation patterns also seem to be consistent with observed cracking behavior. The
results also imply that fracture in mixtures can be modeled effectively using a micromechanical
approach that allows for crack growth both along aggregate surfaces, as well as through
aggregates. Finally, the non-linear Mohr-Coulomb type of failure envelope used to model the
mastic appears to result in reasonable predictions. It can be concluded that the explicit fracture
modeling with the displacement discontinuity boundary element method has the potential to
evaluate the mechanics of fracture in asphalt mixtures.
Key Words: Hot mix asphalt, indirect tension test, boundary elements, fracture mechanics
TRB 2003 Annual Meeting CD-ROM Original paper submittal – not revised by author.
Back to Table of Contents
Three-Dimensional Finite Element Analysis Of Measured Tire Contact Stresses And Their
Effects On Instability Rutting Of Asphalt Mixture Pavements
Marc Novak
University of Florida
Graduate Student
Department of Civil and Coastal Engineering
P.O. Box 116580
Gainesville, FL 32611-6580
Telephone: (352) 392-0769
Fax: (352) 392-3394
E-mail: men@ufl.edu
Dr. Bjorn Birgisson
University of Florida
Assistant Professor
Department of Civil and Coastal Engineering
P.O. Box 116580
Gainesville, FL 32611-6580
Telephone: (352) 392-9537
Fax: (352) 392-3394
E-mail: bbirg@ce.ufl.edu
Dr. Reynaldo Roque
University of Florida
Professor
Department of Civil and Coastal Engineering
P.O. Box 116580
Gainesville, FL 32611-6580
Telephone: (352) 392-9537
Fax: (352) 392-3394
E-mail: rroqu@ce.ufl.edu
ABSTRACT
Instability rutting generally occurs within the top two inches of the asphalt layer when the
structural properties of the asphalt concrete are inadequate to resist the stresses imposed upon it.
Several researchers have presented observations in attempts to explain instability rutting, but a
clear identification of the mechanism does not exist. Stresses in the asphalt layer caused by
measured tire interface stresses were analyzed in three-dimensions using finite elements in an
attempt to identify possible mechanisms for instability rutting. The analysis showed that radial
tires produce high near surface shear stresses at low confinements, which are not predicted with
traditional uniform vertical loading conditions, in the region where instability rutting is known to
occur. The resulting shear stresses tend to be shallower than for the uniformly loaded case, and
focused in areas where instability rutting has been observed. The observed stress states imply
that the characterization of instability rutting requires testing at these low confinement (and
sometimes tensile) stress states, rather than at the higher stress states typically used in the
strength characterization of mixtures.
Keywords: rutting instability, shear instability, hot mix asphalt, flexible pavements, finite
elements.
Back to Table of Contents
Ultrasonic Pulse Wave Velocity Test As A Tool For Monitoring Changes In Hma Mixture
Integrity Due To Exposure To Moisture
Bjorn Birgisson
(Corresponding Author)
Assistant Professor
Department of Civil and Coastal Engineering
University of Florida, 345 Weil Hall, P. O. Box 116580
Gainesville, FL 32611-6580
Tel: (352) 392-9537
Fax: (352) 392-3394
Email: bbirg@ce.ufl.edu
Reynaldo Roque
Professor
Department of Civil Engineering, University of Florida
345 Weil Hall, P. O. Box 116580
Gainesville, FL 32611-6580
Tel: (352) 392-9537 ext. 1458
Fax: (352) 392-3394
Email: rroqu@ce.ufl.edu
Gale C. Page
State Bituminous Materials Engineer
Florida Department of Transportation
State Materials Office
2006 NE Waldo Road
Gainesville, FL 32609
Tel: (352) 337-3100
Fax: (352) 334-1648
E-mail: gale.page@dot.state.fl.us
ABSTRACT
In this paper, the ultrasonic pulse wave velocity test is evaluated as a possible tool for monitoring
changes in the integrity of mixtures due to moisture conditioning. Two sets of mixtures were
prepared. The first group involved fine-grained (above restricted the zone) and coarse-grained
(below the restricted zone) limestone mixtures commonly used by the Florida Department of
Transportation (FDOT) that were produced with multiple void structure and permeability
configurations by varying the gradations and proportions for a common set of aggregates and
asphalt cement. The second set of mixtures consisted of three granite-based mixtures commonly
used by the FDOT. The results presented show that the MAll strain modulus obtained with the
ultrasonic pulse wave velocity test appears to be sensitive to changes in mixture integrity due to
moisture, and therefore may be a possible tool for the characterization of damage in both
laboratory and field specimens. Additional work remains to be performed to define better the
meaning of the values obtained. However, the current results indicate that the ultrasonic pulse
wave velocity test may be used as an indicator of damage in specimens, as well as a quick
monitoring device for detecting changes in the integrity of mixtures due to the exposure to
moisture.
Keywords: Nondestructive testing, pulse wave velocity, moisture damage, hot mix asphalt
Back to Table of Contents
Use Of Screenings To Produce HMA Mixtures
L. Allen Cooley, Jr., Manager, Southeastern Superpave Center
National Center for Asphalt Technology, 277 Technology Parkway, Auburn, AL 36830
Office: (334) 844-6228, Fax: (334) 844-6248, email: coolela@eng.auburn.edu
Michael H. Huner,District Engineer
Asphalt Institute, 415 Bridge St., Franklin, TN 37064
Office: (615) 599-3939, Fax: (615) 599-4645, email: mhuner@asphaltinstitue.org
Jingna Zhang, Research Engineer
National Center for Asphalt Technology, 277 Technology Parkway, Auburn, AL 36830
Office: (334) 844-6228, Fax: (334) 844-6248, email: zhangj1@eng.auburn.edu
E. Ray Brown, Director
National Center for Asphalt Technology, 277 Technology Parkway, Auburn, AL 36830
Office: (334) 844-6228, Fax: (334) 844-6248, email: rbrown@eng.auburn.edu
ABSTRACT
Thin-lift hot mix asphalt (HMA) layers are utilized in almost every maintenance and
rehabilitation application. These mix types require smaller maximum particle sizes than most
conventional HMA surface layers. Although the primary functions of thin-lift HMA are to level
the pavement surface, smooth the surface, and/or slow the deterioration of the existing pavement,
these mixes may also provide some structural improvement, depending on the layer thickness
placed. The use of manufactured aggregate screenings (fine aggregate stockpiles) as the sole
aggregate portion of an HMA mixture was evaluated in this study. Mixes of this nature have the
potential for use as thin-lift HMA layers. Two different sources of aggregate screenings, granite
and limestone, were utilized to design mixtures at varying design air void contents and then
tested for rut susceptibility. The use of a neat versus modified asphalt binder was also evaluated,
as well as evaluating potential advantages of cellulose fiber additives. These mixtures using 100
percent manufactured screenings proved to be acceptable with regards to rutting resistance. No
work was performed in this study to look at thermal cracking or durability.
KEYWORDS
Hot-Mix Asphalt, Coarse Graded, Screenings, Design Air Void Content, Binder Type,
Fiber, Voids Filled With Asphalt, Rutting Resistance, Design Criteria, Thin-Life Maintenance
Back to Table of Contents
Aggregate Imaging System (AIMS) For Characterizing The Shape Of Fine And Coarse
Aggregates
Thomas Fletcher, Civil Engineer
US Army Corps of Engineers
Walla Walla District
Tel: (509) 527 7625
Fax: (509) 527 7812
Email: Thomas.W.Fletcher@nww01.usace.army.mil
Chandan Chandan, Graduate Research Assistant
School of Electrical Engineering and Computer Science
Washington State University
Pullman, WA 99164
Tel: (509) 335-2348
Email: chandan@eecs.wsu.edu
Eyad Masad, Assistant Professor
Department of Civil and Environmental Engineering
Washington State University
Pullman, WA 99164-2910
Tel: (509) 335 9147
Fax: (509) 335 7632
Email: masad@wsu.edu
Krishna Sivakumar
School of Electrical Engineering and Computer Science
Washington State University
Pullman, WA 99164
Tel: (509) 335 4969
Email: siva@eecs.wsu.edu
ABSTRACT
This paper presents the design and development of a unified computer automated system for
characterizing the shape of fine and coarse aggregates. It describes the unique features of the
system and the experimental design considerations. These considerations are related to the
required image resolution, field of view, and lighting scheme. The unique features of the system
include the ability of analyzing fine and coarse aggregate, quantifying texture, angularity and the
three-dimensions of form. The developed system is used to measure aggregate shape properties
for a wide range of fine and coarse aggregates, and the results are compared with hot mix asphalt
(HMA) laboratory performance. The analysis shows that the developed procedure yields detailed
information on shape properties of aggregates in a short time. The measurements have very good
correlation with the resistance of asphalt mixes to permanent deformation measured in the
laboratory using different wheel tracking devices.
Back to Table of Contents
Analytical Formulas for Film Thickness in Compacted Asphalt Mixture
Boris Radovskiy
Consultant
11977 Kiowa Avenue, # 109, Los Angeles, CA 90049
Tel. 310-207-4740 and Fax 310-207-3686
E-mail: b.radovskiy@worldnet.att.net
ABSTRACT
Several researchers have recently proposed the asphalt film thickness as a criterion for ensuring
durability of asphalt mixtures. However, it was suggested that the standard film thickness
equation dating back to the 1940s needs to be examined by modern technology and improved. In
this paper, a presumable background on which the Asphalt Institute surface area factors are
based is recovered and analyzed in details. A fundamentally sound model for film thickness
calculation is developed using a model of asphalt concrete in which the aggregates are spherical,
but with arbitrary size distribution. A recent result from statistical geometry is applied to
determine the film thickness for any volume fraction of aggregates and any volume fraction of
effective asphalt. The analytical formulas are presented, the details of the calculation are
summarized and examples provided.
Back to Table of Contents
Asphalt Pavement Quality Control/Quality Assurance Programs In The United States
Nathan E. Butts
Graduate Research Assistant
Department of Civil and Architectural Engineering
University of Wyoming
P.O. Box 3295, University Station
Laramie, Wyoming 82071
Tel: (307) 766-5255
Fax: (307) 766-2221
E-mail: buttsn@uwyo.edu
Khaled Ksaibati, Ph.D., P.E.
Professor of Civil Engineering
Department of Civil and Architectural Engineering
University of Wyoming
P.O. Box 3295, University Station
Laramie, Wyoming 82071
Tel: (307) 766-6230
Fax: (307) 766-2221
E-mail: khaled@uwyo.edu
ABSTRACT
Many of the State highway agencies (SHAs), in recent years, have adopted quality
control/quality assurance (QC/QA) specification programs for the construction of asphalt
pavements. This new specification is meant to improve the quality of the pavements through
frequent testing and monitoring throughout the production and placement of the hot mix asphalt.
With a QC/QA specification, the Contractor is responsible for the quality of the pavement, while
the highway agency is responsible for the acceptance, rejection and/or price adjustment of that
product. The University of Wyoming and the Wyoming Department of Transportation has
combined their efforts to evaluate the effectiveness of QC/QA on the national level. In order to
achieve this goal, a basic understanding of the status quo of the QC/QA programs is essential. A
survey was prepared and distributed to the 50 SHAs to contrast and compare various QC/QA
programs. Results of the survey indicated that 40 of 45 responding SHAs or nearly 90% have
implemented an asphalt pavement construction QC/QA specification program. Although the first
program emerged as early as in 1968, most of the programs were implemented after 1985,
indicating that QC/QA are still in the stages of development. Different SHAs have different
versions of QC/QA, which may vary significantly in the scope of QC/QA, QC responsibility, QA
responsibility, QA testing, properties to be tested, certification of testers, variable control level,
and incentive and disincentive policies. Previous evaluations of QC/QA by individual SHAs
have resulted in positive reviews.
Back to Table of Contents
Do Asphalt Mixtures Correlate Better with Mastics or Binders in Evaluating Permanent
Deformation?
Aroon Shenoy
Senior Research Rheologist
Turner-Fairbank Highway Research Center
6300 Georgetown Pike, McLean, VA 22101
Tel: 202-493-3105; Fax: 202-493-3161; e-mail: aroon.shenoy@fhwa.dot.gov
Kevin Stuart
Research Highway Engineer
Turner-Fairbank Highway Research Center
6300 Georgetown Pike, McLean, VA 22101
Tel: 202-493-3073; Fax: 202-493-3161; e-mail: kevin.stuart@fhwa.dot.gov
Walaa Mogawer
Professor
University of Massachusetts-Dartmouth
285 Old Westport Rd, Dartmouth, MA 02747-2300
Tel: 508-999-8468; Fax: 508-999-8964; e-mail: Wmogawer@umassd.edu
ABSTRACT
Researchers have often looked for relationships between the mechanical properties of the asphalt
mixtures and the rheological properties of the binders when assessing the resistance of the
mixtures/binders to permanent deformation. When mixtures are subjected to deformation upon
application of a stress, the aggregates act as load-bearing entities while the binders deform in
response to the applied stress. Intuitively it thus seems obvious that some sort of correlation
must exist between the properties of the mixtures and the binders. However, most often it is
observed that a good correlation does not exist. There could be a number of different reasons for
the observed poor correlations. There could be variability in the data, or possible change in the
microstructure of two-phase polymer-modified asphalt in the presence of aggregates, or possibly
strong interactions between the aggregate and the binder that, of course, does not get reflected in
the binder properties. In such cases, there are reasons to believe that asphalt mastics might
provide a better correlation because they would account for at least the physicochemical aspects
of the aggregate-binder interaction.
The present work compares asphalt mixture data initially with the mastic data and then
separately with the binder data. The mastic and binder rheological data are generated using the
same equipment under identical conditions of measurement, thus making it possible to identify
the one that correlates better with the mixture data. A good correlation is obtained only in one
case when Superpave Shear Tester data for mixtures are compared with the Dynamic Shear
Rheometer data for binders. In all cases analyzed in this work, there is no correlation found
between the permanent deformation for mixtures and the rheological properties of the mastics.
Keywords: Rheological data, asphalt binder, asphalt mastic, asphalt mixture evaluation,
Superpave shear tester, French pavement rutting tester, Hamburg wheel-tracking device,
Back to Table of Contents
Lessons Learned From Trucking Operations At The Ncat Pavement Test Track
Jennifer Still
The National Center for Asphalt Technology
277 Technology Parkway
Auburn, AL 36830
Phone: (334) 844-6228
Fax: (334) 844-6853
stilljl@auburn.edu
ABSTRACT
An experimental facility has been constructed near the campus of Auburn University for the
purpose of conducting research to extend the life of flexible pavements. The National Center for
Asphalt Technology’s Pavement Test Track is a full-scale accelerated loading test oval. To
achieve the necessary traffic on the Track, tractor-trailer assemblies were utilized. This paper
documents all aspects of the trucking operations for the two-year project in hopes that on-going
and future research may benefit from the lessons learned at the NCAT Pavement Test Track.
Back to Table of Contents
Pavement Surface Macrotexture Measurement and Application
Gerardo W. Flintsch
Assistant Professor, The Via Department of Civil and Environmental Engineering
Transportation Fellow, Virginia Tech Transportation Institute
200 Patton Hall, Virginia Polytechnic Institute and State University
Blacksburg, VA 24061-0105
voice (540) 231 9748, fax (540) 231 7532
email: flintsch@vt.edu
Edgar de León
Graduate Research Assistant, Virginia Tech Transportation Institute
3500 Transportation Research Plaza
Blacksburg, VA 24061-0105
voice (540) 231 1568, fax (540) 231 1555
email: edeleoni@vt.edu
Kevin K. McGhee
Senior Research Scientist, Virginia Transportation Research Council
530 Edgemont Road
Charlottesville, VA 22903
voice (434) 293-1956, fax (434) 293-1990
email: McGheeKK@vdot.state.va.us
Imad L. Al-Qadi
Charles E. Via, Jr., Professor of Civil and Environmental Engineering
Leader, Roadway Infrastructure Group, Virginia Tech Transportation Institute
200 Patton Hall, Virginia Polytechnic Institute and State University
Blacksburg, VA 24061-0105
voice (540) 231 5262, fax (540) 231 7532
email: alqadi@vt.edu.
Virginia Tech Transportation Institute, Virginia Tech, Blacksburg, VA
ABSTRACT
This paper discusses different techniques for measuring pavement surface macrotexture and its
application in pavement management. The main applications of surface macrotexture are to
measure the frictional properties of the pavement surface and to detect hot mix asphalt (HMA)
construction segregation or non-uniformity. Since surface macrotexture can be measured quite
efficiently using noncontact technologies and provides important information regarding
pavement safety and HMA construction quality, this parameter may be included in the quality
assurance or control procedures. Correlations between different measuring devices were
investigated utilizing different HMA wearing surfaces. Excellent correlation was found between
the CTMeter and the sand patch measurements. In addition, the Mean Profile Depth (determined
using a laser profiler) correlates well with the sand patch measurements. Consistent with
previous studies, it was found that the skid number gradient with speed is inversely proportional
to the pavement macrotexture. However, there was a noticeable difference in speed dependency
when using the smooth and ribbed tires and oscillations in the percent normalized gradient with
time due to seasonal variations were observed. Macrotexture measurements hold great promise
as tools to detect and quantify segregation for quality assurance purposes. A standard
construction specification has been proposed in a recent NCHRP study. However, the equation
proposed for computing the non-segregated ETD could not be applied to the mixes studied. An
alternative equation has been proposed, which estimates the surface macrotexture using the mix
nominal maximum size and voids in the mineral aggregate. Further investigation using other
mixes than the ones used at the Virginia Smart Road is recommended.
Back to Table of Contents
The Time-Temperature Superposition For Asphalt Mixtures With Growing Damage And
Permanent Deformation In Compression
Yanqing Zhao
Graduate Research Assistant
Department of Civil Engineering
North Carolina State University
Raleigh, NC
E-mail: yzhao3@unity.ncsu.edu
Y. Richard Kim (Corresponding Author)
Professor
Deptartment of Civil Engineering, Campus Box 7908
North Carolina State University
Raleigh, North Carolina 27695
Ph: (919) 515-7758
Fax: (919) 515-7908
Email: kim@eos.ncsu.edu
ABSTRACT
The objective of this paper is to check the validity of the time-temperature superposition
principle for hot-mix asphalt (HMA) with growing damage and viscoplastic strain in the
compression state, which is essential for the permanent deformation characterizaton of HMA.
Constant crosshead rate compression tests were conducted at temperatures between 25 and 55C,
and data were analyzed to construct the stress-log reduced time master curves for various strain
levels. Research results indicate that HMA with growing damage remains thermorheologically
simple (TRS) in the temperature range used in this study, and that the time-temperature shift
factor is only a function of temperature and is independent of the strain level. Two types of tests,
the repeated creep and recovery test and the cyclic sinusoidal loading test, were performed in this
study to validate the timetemperature superposition in loading histories commonly used in
asphalt mixture testing. The results further confirm that the time-temperature superposition is
valid for HMA with growing damage and permanent deformation and that the response of HMA
only depends on the reduced loading history.
Keywords: time-temperature superposition, growing damage, shift factor, compression
Back to Table of Contents
A Commentary on FDOT Technician Certification Program
Charles Nunoo Ph.D., P.Eng.
Assistant Professor / Advisor
Civil and Environmental Engineering Department
Florida International University
10555 West Flagler Street
Miami, FL 33174
Tel: 305-348-4102 Fax: 305-348-2802
Email: cnunoo@eng.fiu.edu
Hasham Ali, Ph.D., PE
District Materials Engineer
Florida Department of Transportation
14200 W State Rd. 84
Davie, FL 33325
Email: Hesham.ali@dot.state.fl.us
Felix Delgado
Student Assistant
Civil and Environmental Engineering Department
Florida International University
10555 West Flagler Street
Miami, FL 33174
Tel: 305-528-1595
Email: felixhdo@yahoo.com
ABSTRACT
The Florida Department of Transportation (FDOT) has recently revamped its materials quality
assurance practice. The new philosophy advocates improving the technical qualifications of
technicians involved in materials sampling and testing. The higher level of professionalism
allows FDOT to rely on Contractors personnel to be in full charge of their quality control, and
reduce the Department’s materials sampling and testing responsibility. The new quality control
system is based on several component programs that must function together in a complementary
manner. The first is the Construction Training and Qualification Program (CTQP), which are
designed to provide the training and certification of technicians in several materials areas. The
second is the Independent Assurance Program (IA), which is aimed at evaluating the
performance of construction technicians while performing their duties. The third is the new
specifications (referred to as QC 2000) that give the contractor the ability to be in full charge of
his production through quality control testing, with limited verification testing performed by
Department personnel. The fourth is the Laboratory Qualification Program that allows the
contractor to use a private laboratory to perform materials sampling and testing for acceptance
purposes, subject to approval and qualification of the laboratory by the Department. This paper
describes the training and qualification program (CTQP) used by FDOT and some of the
perceived advantages and disadvantages of the new system, compared to the old system and to
practices in other state DOT’s. This paper is based on extensive information review and expert
opinion by the authors.
KEY WORDS
Construction Quality Assurance, Materials, Sampling and Testing, Technician Qualification,
Independent Assurance, FDOT.
Back to Table of Contents
Creep Compliance of Polymer Modified Asphalt, Asphalt Mastic and Hot Mix Asphalt
Ota J. Vacin
Graduate Student
Tel.(403) 220-2722
Fax. (403) 282-7026
ojvacin@ucalgary.ca
Jiri Stastna
Adjunct Professor
Tel. (403) 220-7179
Fax. (403) 282-7026
stastna@ucalgary.ca
Ludo Zanzotto
Professor
Tel.(403) 220-8918
Fax. (403) 282-7026
lzanzott@ucalgary.ca
Address: University of Calgary, Dept. of Civil Engineering, Bituminous Materials Chair,
2500 University Drive N.W., Calgary, Alberta, Canada, T2N 1N4
ABSTRACT
A possibility to use commercial rheometers for comprehensive testing of asphalt binders, asphalt
mastics and hot mix asphalts (HMA) is explored in this contribution. Samples of one polymer
modified asphalt; its mix with fine mineral filler (mastic) and one HMA prepared with the same
modified asphalt as binders were tested in the dynamic shear rheometer (DSR) and the bending
beam rheometer (BBR). All tested materials can be characterized by their discrete relaxation and
retardation spectra (under the condition of small deformations). DSR testing was done in the
plate-plate and the torsion bar geometry. From the obtained relaxation and retardation spectra the
shear compliance J(t) was calculated and compared with the tensile creep compliance, D(t),
measured in BBR (both creep and recovery experiments were run). A simple relation between
J(t) and D(t) was found for the asphalt binder and asphalt mastic. In the case of HMA the bulk
compliance, B(t), contributes to D(t) at short and long times. Both the Boltzmann superposition
principle and the time temperature superposition principle hold for all tested materials, at low
temperatures, very well. There are qualitative differences, in the rheological behaviour, of the
asphalt binder and asphalt mastic on one side and the HMA on the other. These differences can
be seen in dynamic (DSR) as well as in transient (BBR) experiments.
Back to Table of Contents
Design, Construction And Early Performance Of Foamed Asphalt Full Depth Reclaimed
(FDR) Pavement In Maine
Brian Marquis1, Richard L. Bradbury1, Stephen Colson1, Rajib B. Mallick2, Yamini V. Nanagiri2,
Jonathan S. Gould2 and Mike Marshall3
1. Maine Department of Transportation, 2. Civil and Environmental Engineering Department, Worcester
Polytechnic Institute, 3. Wirtgen, GmbH
ABSTRACT
Maine Department of Transportation constructed its first foamed asphalt full depth reclamation
project in June 2001. The objectives of this study are to evaluate ME DOT’s foamed asphalt
design and construction procedures and make appropriate recommendations for improving the
performance of foamed asphalt reclaimed pavements. The scope of work reported in this paper
consists of testing one year old cores for density and stiffness, determination of asphalt content
and gradation of cores, comparison of density and stiffness of laboratory mix design samples
with density and stiffness of in-place cores and a review of falling weight deflectometer results.
It is concluded that because of the variable nature of thick pavement layers, a high variation in
density and asphalt content of foamed asphalt reclaimed layers can be expected, and that
variation in density of layers can affect stiffness significantly. Moisture susceptibility testing
with cyclic loading in water showed that foamed asphalt mixes were not inferior to emulsion
plus lime mixes. Sections with thicker HMA showed significantly lower cost per percent
increase in modulus. Back calculation analysis with falling weight deflectometer data from 10
month old pavement showed a modulus of 1,055 Mpa for a foamed asphalt layer of 200 mm
thickness, with 60 % Recycled Asphalt Pavement material, 15 % granular material, 25 % crusher
dust, 1.5 % cement and with 2.5 % foamed asphalt. Use of heavier rollers in compaction of
foamed asphalt reclaimed layers is recommended.
Key words: foamed asphalt, full depth reclamation, density, moisture susceptibility, stiffness
Back to Table of Contents
Development And Validation Of A Model To Predict Pavement Temperature Profile
Brian K. Diefenderfer
Project Manager, Concorr, Inc.
45710 Oakbrook Court, Suite 160
Sterling, VA 20166
Email: bdief@concorr.com
Phone: 571 434-1852
Fax: 571 434-1851
Imad L. Al-Qadi, Charles E. Via, Jr. Professor of Civil and Environmental Engineering
Via Department of Civil and Environmental Engineering and Virginia Tech Transportation Institute
3500 Transportation Research Plaza
Blacksburg, VA 24061
Email: alqadi@vt.edu
Phone: 540 231-1503
Fax: 540 231-1555
Stacey D. Reubush
Graduate Research Assistant, Via Department of Civil and Environmental Engineering
and Virginia Tech Transportation Institute
3500 Transportation Research Plaza
Blacksburg, VA 24061
Email: doodle@vt.edu
Phone: 540 231-1553
Fax: 540 231-1555
Thomas E. Freeman
Senior Research Scientist, Virginia Transportation Research Council, VDOT,
530 Edgemont Road
Charlottesville, VA 22903
Email: Tom.Freeman@viginiadot.org
Phone: 434 293-1957
Fax: 434 823-7978
ABSTRACT
Flexible pavements comprise a majority of the primary highways in the United States. These
primary roads are subjected to heavy loading that can cause significant damage to the hot-mix
asphalt (HMA) pavements. As HMA is a viscoelastic material, the structural or load-carrying
capacity of the pavement varies with temperature. Thus, to determine in-situ strength
characteristics of flexible pavement, it is necessary to predict the temperature distribution within
the HMA layers. The majority of previously published research on pavement temperature
prediction has consisted of predicting the annual maximum or minimum pavement temperature
so as to recommend a suitable asphalt binder performance grade. To determine the pavement
temperature profile, the influence of ambient temperature and seasonal changes must be
understood such that the effects of heating and cooling trends within the pavement structure can
be quantified. Recent investigations have shown that it is possible to model daily pavement
maxima and minima temperature by knowing the maximum or minimum ambient temperatures,
the depth at which the pavement temperature is desired, and the day of year at a particular
location. This paper extends that model to incorporate either the calculated daily solar radiation
or latitude such that the model can be applied to any location. The suggested location
independent model was successfully validated utilizing data from the Virginia Smart Road and
two LTPP-SMP sites.
Back to Table of Contents
Development Of A New Test Procedure For Determining The Bulk Specific Gravity Of
Fine Aggregate Using Automated Methods
Nolan V. Baker
Graduate Research Assistant
National Center for Asphalt Technology
277 Technology Parkway
Auburn, AL 36830
Phone: (334) 844-6228
Fax: (334) 844-6248
Email: NolanBaker@Hotmail.com
Brian D. Prowell
Assistant Director
National Center for Asphalt Technology
277 Technology Parkway
Auburn, AL 36830
Phone: (334) 844-6228
Fax: (334) 844-6248
Email: Bprowell@eng.auburn.edu
E. Ray Brown
Director
National Center for Asphalt Technology
277 Technology Parkway
Auburn, AL 36830
Phone: (334) 844-6228
Fax: (334) 844-6248
Email: Rbrown@eng.auburn.edu
ABSTRACT
This study evaluated two automated methods for determining the BSG of fine aggregates, the
Gilson SSD50 and InstroTek Corelok. Each proposed method was evaluated against the standard
method described in AASHTO T-84. Three operators each tested ten replicates each on seven
different fine aggregate sources, four natural sands and 3 crushed screenings. Both the Gilson
and InstroTek devices appear to provide low absorption results when using high absorptive
crushed aggregates. This did not appear to be the case for high absorptive rounded sands. The
initial evaluation of the prototypes indicated drawbacks of both methods. The Gilson device has
problems with aggregates containing high fines and some repeatability issues. Overall, the
Gilson device produced results that were the closest to AASHTO T-84. The InstroTek device
generally overestimated absorption. This is believed to be caused by entrapped air in the
pycnometer used to determine the sample bulk volume. The InstroTek device indicates improved
repeatability for bulk and apparent specific gravity measurements. Both manufacturers believe
that additional modifications to the equipment or test method will improve results.
Back to Table of Contents
Development Of A Rational Procedure For Evaluation Of Moisture Susceptibility Of
Asphalt Paving Mixes
Rajib B. Mallick1
Jonathan S. Gould1
Sudip Bhattacharjee1
Ali Regimand2
Lawrence H. James2
Elton Ray Brown3
1 – CEE Department, Worcester Polytechnic Institute (WPI), 2 – InstroTek Inc., 3 – National Center for Asphalt
Technology (NCAT)
ABSTRACT
Proper testing and screening for moisture susceptibility is a crucial requirement for designing
good performing asphalt pavements. The objective of this ongoing study is to develop a rational
procedure for evaluation of moisture susceptibility of asphalt paving mixes. Theoretical
considerations show that pore pressure generated under saturated undrained condition is
significantly higher than that generated under drained condition. Some preliminary tests with a
modified existing equipment indicated that conditioning process of applying cyclic pressure of
35-210 kPa at 5 Hz and 60oC is able to induce moisture damage within one hour. A new
standalone equipment was used for conditioning samples of two mixes – one with and another
without moisture susceptibility problems. The equipment consists of a system to use a supply of
compressed air to load and apply vacuum to force water out and in through a sample. Results
were compared to results obtained from AASHTO T283 and rut testing under water. It was
concluded that the new procedure has good potential for use as a method for evaluation of
moisture susceptibility of mixes. It is capable of repetitive generation of pore pressure and
suction, causing hydraulic scouring of mixes, and causing progressive moisture damage with
increasing number of cycles. The process has good repeatability and is sensitive to temperature
and mix types. It is recommended that further improvement of this equipment and refinement of
the test procedure be carried out and research be conducted with different types of mixes,
especially with aggregates/mixes susceptible to stripping.
Key words: moisture damage, stripping, hydraulic scouring, asphalt, FEM
Back to Table of Contents
Evaluation Of Infrared Ignition Furnace For Determination Of Asphalt Content
Graham C. Hurley
Research Engineer
National Center for Asphalt Technology
277 Technology Park
Auburn, AL 36832
Phone: (334) 844-6228
Fax: (334) 844-6248
Email: hurlegc@eng.auburn.edu
Brian D. Prowell
Assistant Director
National Center for Asphalt Technology
277 Technology Park
Auburn, AL 36832
Phone: (334) 844-6228
Fax: (334) 844-6248
Email: bprowell@eng.auburn.edu
ABSTRACT
This study evaluated the Troxler Model 4730 infrared ignition furnace as compared to a standard
Thermolyne ignition furnace. Comparisons conducted on a single unit of each furnace type were
based on correction factor for aggregate loss during ignition, accuracy and variability of the
measured asphalt content, and aggregate degradation during ignition. Forty-eight samples,
representing two nominal maximum aggregate sizes (9.5 and 19.0 mm), four aggregate types
(granite, crushed gravel, limestone and dolomite) and two asphalt contents (optimum and
optimum plus 0.5 percent asphalt content) were tested in each furnace. The results indicated that
the correction factors for aggregate loss during ignition were significantly different for each type
of furnace, thus requiring a separate calibration for each type of furnace. Practically, the
differences for all but the 9.5 mm NMAS limestone and both dolomite mixtures are less than 0.1
percent. The samples at optimum plus 0.5 percent asphalt content were tested using the
calibration factors developed for a particular mix/furnace combination. The results were
analyzed in terms of accuracy (bias) and variability (standard deviation). Neither the measured
bias’ nor standard deviations for the two types of furnaces were significantly different. Results
from four sieve sizes (NMAS, 4.75, 2.36 and 0.075 mm) were evaluated for aggregate
breakdown. A comparison of the recovered aggregate gradations from both furnaces indicated no
significant difference in the degree of aggregate degradation. A round robin should be conducted
to confirm that the precision of the infrared furnace is similar to the precision of the standard
furnace.
Back to Table of Contents
Evaluation Of Moisture Susceptibility Of Asphalt Mixtures Containing Bottom Ash
Menglan Zeng, Ph.D.
Postdoctoral Research Assistant
Department of Civil and Architectural Engineering
University of Wyoming
P.O. Box 3295, University Station
Laramie, Wyoming 82071
Tel: (307) 766-3031, Fax: (307) 766-2221
E-mail: zeng@uwyo.edu
Khaled Ksaibati, Ph.D., P.E.
Professor of Civil Engineering
Department of Civil and Architectural Engineering
University of Wyoming
P.O. Box 3295, University Station
Laramie, Wyoming 82071
Tel: (307) 766-6230, Fax: (307) 766-2221
Email: Khaled@uwyo.edu
ABSTRACT
Bottom ash, as a byproduct of coal fired electric power plants, has recently been used in
constructing transportation facilities. However, the use of bottom ash in asphalt mixture is still in
early stages. The moisture resistance of asphalt mixtures containing bottom ash was not
adequately researched. This study investigated the moisture susceptibility of asphalt mixtures
containing bottom ash. Eight asphalt mixtures produced with one type of asphalt cement, two
types of aggregate, three sources of bottom ash, and lime additive were evaluated using the
principles in AASHTO T283. Analysis on test data indicated that granite mixtures had higher
tensile strength (TS) values than limestone mixtures in dry condition. The lime or bottom
addition did not substantially change TS values. All mixtures tested met the Superpave
volumetric mix design requirement of tensile strength ratio (TSR) after one freeze-thaw cycle.
The addition of lime significantly improved the moisture susceptibility of the asphalt mixtures as
measured by TSR. With lime addition aggregate type, bottom ash addition, and bottom ash
source were all insignificant with respect to TSR. Based on TSR rate (TSRR) values, the
addition of lime also significantly improved the moisture susceptibility of the asphalt mixtures
subjected to multiple freeze-thaw cycles, while lime addition aggregate type and bottom ash
addition were insignificant. However, bottom ash source was a factor statistically significant in
relating to TSRR, which was not found for TSR. Without lime addition, bottom ash played a role
similar to lime in improving TSRR for the materials tested.
Back to Table of Contents
Quantitative Field Evaluation and Effectiveness of Fine Mix under HMA Base in Flexible
Pavements
Imad L. Al-Qadi, Charles E. Via, Jr. Professor of Civil and Environmental Engineering
200 Patton Hall, Virginia Tech
Blacksburg, VA 24061
Email: alqadi@vt.edu, Phone: 540 231-5262; Fax: 540 231-7532
Amara Loulizi, Research Scientist
Virginia Tech Transportation Institute
3500 Transportation Research Plaza
Blacksburg, VA 24061
Email: amlouliz@vt.edu, Phone: 540 231-1504; Fax: 540 231-1555
Samer Lahouar, Graduate Research Assistant
Virginia Tech Transportation Institute
3500 Transportation Research Plaza
Blacksburg, VA 24061-0536
e-mail: slahouar@vt.edu, Tel: 540 231-1588, Fax: 540 231-1555
Gerardo W. Flintsch, Assistant Professor
The Via Department of Civil and Environmental Engineering
200 Patton Hall, Virginia Tech
Blacksburg, VA 24061-0105
email: flintsch@vt.edu, voice (540) 231 9748, fax (540) 231 7532
Thomas E. Freeman, Senior Research Scientist
Virginia Transportation Research Council, VDOT,
530 Edgemont Road
Charlottesville, VA 22903
Email: Tom.Freeman@viginiadot.org, Phone: 434 293-1957; Fax: 434 823-7978
ABSTRACT
The main objective of this study was to predict the effect of incorporating a fine hot-mix asphalt
(HMA) layer under HMA base on the long term fatigue performance of flexible pavements.
Testing at the Virginia Smart Road allowed the determination of the vertical compressive stress
and horizontal transverse strain induced by a steering-axle tire of 25.8kN (5800lbs) under the
hot-mix asphalt (HMA) layer of two pavement designs, one of which included a fine surface mix
below a base mix. Stresses and strains were measured for four different speeds (8, 24, 40, and
72km/h (5, 15, 25, and 45mph)), three tire inflation pressures (552, 655, and 724kPa (80, 95, and
105psi)), and under different temperatures. Stresses were measured using pressure cells while
strains were measured using H-Type strain gages embedded in the HMA layers during
construction. As expected, temperature was found to significantly affect the measured vertical
compressive stresses and measured horizontal transverse strains under the HMA layer. Speed, on
the other hand, did not affect the magnitude of the measured vertical compressive stress in all
layers, but did affect the loading time. However, speed was found to significantly affect the
measured horizontal transverse strain under the HMA layer. Measured compressive stress and
horizontal transverse strain at the bottom of the HMA layer at depths greater than 150mm (6in)
were found to be independent of tire inflation pressure ranges from 552kPa (80psi) to 724kPa
(105psi). It appears that incorporation of a fine mix at the bottom of a base HMA layer would
increase the fatigue life of flexible pavements.
Back to Table of Contents
Utilizing Pavement Evaluation Data in Rehabilitation Design in MDSHA
Tim Smith, Acting Pavement Division Chief of the Office of Materials and Technology
Maryland State Highway Administration
2323 W. Joppa Road
Brooklandville, MD 21022
Tel: (410) 321-3110
Fax: (410) 321-3099
TSmith2@sha.state.md.us
Peter Stephanos, Director of the Office of Materials and Technology
Maryland State Highway Administration
2323 W. Joppa Road
Brooklandville, MD 21022
Tel: (410) 321-3110
Fax: (410) 321-3099
PStephanos@sha.state.md.us
ABSTRACT
Maryland State Highway Administration (MDSHA) has implemented a pavement rehabilitation
design approach that attempts to utilize pavement evaluation data and current pavement design
procedures. There are numerous different mechanisms and testing equipment currently utilized
to evaluate the existing structural and functional condition of roadway pavements. In the same
manner, there are many different analysis approaches and design theories that are used in the
pavement industry to develop the pavement design strategies for new roadways and the
rehabilitation of existing roadways. The majority of the pavement rehabilitation design
approaches are based primarily on test site empirical equations or on the experience of the
individuals responsible for the construction management of the project. In addition, most of the
known existing rehabilitation design approaches do not typically utilize current pavement
evaluation techniques to assist in rehabilitation design. MDSHA utilizes pavement evaluation
data collected from deflection testing, ride quality testing, surface friction testing, groundpenetrating radar testing, and pavement surface distress testing to contribute to the development
of our pavement rehabilitation strategies. The pavement evaluation data collected is used along
with the procedures in the “1993 AASHTO Guide for Design of Pavement Structures” to
develop pavement rehabilitation strategies. This paper documents MDSHA’s attempt to utilize
pavement evaluation data to select rehabilitation strategies based on the most effective pavement
engineering design, considering cost to the administration, practicality of construction, and
benefit in terms of service life provided to pavement network.
Back to Table of Contents
Viscoelastic, Viscoplastic, and Damage Modeling of Asphalt Concrete in Unconfined
Compression
Nelson H. Gibson
(Corresponding author)
Department of Civil and Environmental Engineering
University of Maryland
College Park, MD 20742
301.405.0305 (voice)
301.405.2585 (fax)
nelgib@glue.umd.edu
Charles W. Schwartz
Department of Civil and Environmental Engineering
University of Maryland
College Park, MD 20742
301.405.1962 (voice)
301.405.2585 (fax)
schwartz@eng.umd.edu
Richard A. Schapery
Department of Aerospace Engineering and Engineering Mechanics
University of Texas
Austin, TX 78712
512.471.3924 (voice)
512.475.5500 (fax)
schapery@austin.rr.com
Matthew W. Witczak
Department of Civil and Environmental Engineering
Arizona State University
Tempe, Arizona 85287-5306
480.965.2759 (voice)
480.965.0557 (fax)
witczak@asu.edu
ABSTRACT
The purpose of this study was to calibrate a comprehensive constitutive model for asphalt
concrete that includes viscoelasticity, viscoplasticity, and irreversible microstructural damage in
unconfined compression. Three different types of laboratory tests were designed and performed
to calibrate each of these response components. Small strain dynamic modulus tests were used to
calibrate the undamaged linear viscoelastic properties. Cyclic creep and recovery tests to failure
were performed to calibrate the viscoplastic properties. Constant rate of strain tests to failure
were used to calibrate the damage behavior. These tests were performed at a wide range of
temperatures, loading rates, and stress levels. Upon calibration of each individual response, the
model was validated by predicting the results of other constant rate of strain tests at temperatures
and strain rates different from those used in the calibrations. The reasonable predictions at these
different conditions suggests that the comprehensive model can realistically simulate a wide
range of asphalt concrete behavior.
Back to Table of Contents
Implementation of a New Ride Quality Specification in Maryland An Incentive Based
Profile Specification
Peter Stephanos, PE,
Maryland State Highway Administration
2323 West Joppa Road,
Brooklandville, MD 21022
(410) 321-3110 (p)
(410) 321-3099 (f)
pstephanos@sha.state.md.us
Jeffrey Withee
Maryland State Highway Administration
2323 West Joppa Road,
Brooklandville, MD 21022
(410) 321-3115 (p)
(410) 321-3099 (f)
jwithee@sha.state.md.us
John Andrews
Maryland State Highway Administration
2323 West Joppa Road,
Brooklandville, MD 21022
(410) 321-3098 (p)
(410) 321-3099 (f)
jandrews@sha.state.md.us
ABSTRACT
The Maryland State Highway Administration (MDSHA) has developed a new, performance
based construction specification for ride quality. The new specification was developed as a
strategy to meet an objective in the MDSHA business plan that requires the percentage of
smoother pavements to increase statewide over the next five years. The new specification allows
the use of inertial profiler testing devices as well as California style rolling wheel profilographs
and includes incentive and disincentive based pay adjustments for asphalt paving. The
specification includes an innovative approach to establishing acceptable ride quality values that
considers many of the factors that affect the ability to construct a smooth riding surface. In
addition, the specification includes clear identification of pay adjustments that are calculated
using a software application developed by MDSHA. Implementation of the new specification
includes inclusion of the new specification in all projects advertised after July 1, 2001 and efforts
to train construction project personnel in the use of the specification. Future implementation
efforts phase out the use of the California style profilograph by 2004. The following paper
includes a description of the efforts completed to date to develop the new specification and
provides highlights of the new specification.
Back to Table of Contents
Laboratory Evaluation of Asphalt Rubber Mixtures Using the Dynamic Modulus (E*) Test
Kamil E. Kaloush, Ph.D., P.E., Assistant Professor
Arizona State University
Department of Civil and Environmental Engineering
PO Box 875306, Tempe, AZ 85287-5306
Tel (480) 965-5509
Fax (480) 965-0557
e-mail: kaloush@asu.edu
Matthew W. Witczak, Ph.D., P.E., Professor
Arizona State University
Department of Civil and Environmental Engineering
PO Box 875306, Tempe, AZ 85287-5306
Tel (480) 965-2759
Fax (480) 727-7058
e-mail: witczak@asu.edu
Andres C. Sotil, Graduate Research Assistant
Arizona State University
Department of Civil and Environmental Engineering
PO Box 875306, Tempe, AZ 85287-5306
e-mail: andres.sotil@asu.edu
George B. Way, P.E., Chief Pavement Design Engineer
Arizona Department of Transportation
1221 North 21st Avenue, MD 068R
Phoenix, AZ 85009
Tel (602) 712-8085
e-mail: gway@dot.state.az.us
ABSTRACT
For thirty years, the Arizona Department of Transportation has been adding crumb rubber to the
asphalt concrete with remarkable performance. A primary objective of this study was to evaluate
the laboratory performance of these mixtures by conducting the Dynamic Complex Modulus
(E*) test. Field samples of two Asphalt Rubber (AR) mixtures were used: Asphalt-RubberAsphalt-Concrete-Gap-Graded, and Asphalt-Rubber-Asphalt-Concrete-Friction-Course-OpenGraded mixes, which utilized a common base binder grade of PG 58-22. Tests were performed
unconfined and confined (three different levels), and the E* master curves were developed for
each mixture and test condition. The E* test results for the AR mixes were compared with
conventional dense graded mixtures test results available from previous studies at Arizona State
University. A modular (E*) ratio was calculated for all mixtures using a conventional PG 64-22
mixture as a reference. A comparison of the modular ratios was done at 14F and 100F, for a
selected frequency of 10 Hz. For the unconfined tests, at 14F, the AR exhibited the lowest
modular ratio (lowest stiffness) and therefore the best performance against cracking. At 100F,
the AR mixtures had comparatively the lowest stiffness values. However, when the comparison
of the ratios was made with confined test results, the AR mixtures showed higher modulus
values, and therefore, the best performance against permanent deformation. Since the
performance of the AR mixtures have been remarkable in the field, the results of this study
showed the importance of using confined tests when comparing the performance of open graded
to dense graded mixtures.
Back to Table of Contents
Mechanistic Evaluation Of Mineral Fillers On Fatigue Resistance And Fundamental
Material Characteristics
YONG-RAK KIM (Corresponding Author)
Graduate Assistant Research, Texas Transportation Institute
501J CE/TTI Building, Texas A&M University, College Station, Texas 77843-3135
Phone: (979) 845-9914, Fax: (979) 845-0278, E-mail: y-kim@ttimail.tamu.edu
DALLAS N. LITTLE
Professor, Department of Civil Engineering,
601 CE/TTI Building, Texas A&M University, College Station, Texas 77843-3135
Phone: (979) 845-9963, Fax: (979) 845-0278, E-mail: d-little@tamu.edu
INJUN SONG
Graduate Assistant Research, Texas Transportation Institute
601 CE/TTI Building, Texas A&M University, College Station, Texas 77843-3135
Phone: (979) 862-3647, Fax: (979) 845-0278, E-mail: i-song@ttimail.tamu.edu
ABSTRACT
Complex characteristics of fatigue behaviors are evaluated based on test results and their
mechanical analyses. The dynamic shear rheometer (DSR) is used to characterize fundamental
linear viscoelastic properties of asphalt cements and mastics. Various dynamic mechanical tests
using cylindrical sand asphalt samples mixed with pure binders and/or mastics are also
performed to estimate viscoelastic characteristics and fatigue behavior. Two distinctly,
compositionally different asphalt cements; AAD-1 and AAM-1; and two fillers; limestone and
hydrated lime; were selected to assess the filler effect. Test results are analyzed using
viscoealstic theory, a fatigue prediction model based on continuum damage mechanics, and a
rheological composite model. The role of fillers in fatigue resistance is quantified, and induced
mechanisms due to filler addition are investigated. The effect of hydrated lime as a filler, which
is highly binder specific, is further discussed by comparing test results from hydrated lime filler
to test results from limestone filler.
Key Words: Asphalt mastic, Fatigue, Damage, Viscoelasticity
Back to Table of Contents
Whitetopping And Hot-Mix Asphalt Overlay Treatments For Flexible Pavement: A
Minnesota Case History
Tom Burnham, Research Project Engineer
Minnesota Department of Transportation
Office of Materials and Road Research
1400 Gervais Avenue, Maplewood,MN 55109
Phone: (651) 779-5605, Fax: (651) 779-5616
e-mail: tom.burnham@dot.state.mn.us
David Rettner, Geotechnical Engineering Manager
Minnesota Department of Transportation
Office of Materials and Road Research
1400 Gervais Avenue, Maplewood,MN 55109
Phone: (651) 779-5516, Fax: (651) 779-5616
e-mail: rett1dav@dot.state.mn.us
ABSTRACT
In 1993, two hot-mix asphalt overlay and four whitetopping test sections were constructed on
low volume TH 30 in southern Minnesota. A study was undertaken to examine the performance
and costs associated with the test sections after nine years of service. The field testing and
evaluation are described, and the costs incurred through 2001 are tabulated. The hot-mix asphalt
overlay test sections are performing up to their design expectations. Both hot-mix asphalt test
sections have had routine preventative maintenance applied to them, adding to their long-term
cost of operation and ownership. The whitetopping test sections are performing very well at the
midpoint of their design life of 20 years. Most distresses to date are related to poor construction
and materials, rather than inherent design features. Average compressive and flexural strength of
the concrete mix was found to be significantly below the specified design values. Some random
longitudinal cracking has occurred in areas of the whitetopping control section. The doweled test
section has numerous distressed transverse joints caused by dowels near the surface of the slabs.
There is virtually no faulting of the transverse joints, and the ride quality has stabilized. No
maintenance has been performed on the whitetopping sections through 2001. As of 2002, the
most economical design on a year-by-year basis is whitetopping test section 3, which has the
same design as the control section. Based on recent observations, it appears whitetopping is a
good performing and economical rehabilitation option for low volume roads in Minnesota.
Back to Table of Contents
Evaluation Of Rutting Resistance Of Superpave Mixtures With And Without Sbs
Modification By Means Of Accelerated Pavement Testing
Okan Sirin, Assistant Professor of Civil Engineering
University of Gaziantep, 27310 Gaziantep- TURKEY,
Phone: +90 (342) 360-1200 ext 2432, Fax: +90 (342) 360-1107, E-mail: osirin@gantep.edu.tr
Hong-Joong Kim, Graduate Research Assistant
University of Florida, E-mail: gogator76@hanmail.net
Mang Tia (corresponding author), Professor of Civil and Coastal Engineering
University of Florida, P.O. Box 116580, Gainesville, FL 32611-6580
Phone: 352-3929537 X1463, Fax: 352-3923394, E-mail: tia@ce.ufl.edu
Bouzid Choubane
Florida Department of Transportation, Materials Research Park, 5007 N.W. 39 th Avenue, Gainesville, FL 32609
Phone: 352-955-6302, Fax: 352-955-6345, E-mail: bouzid.choubane@dot.state.fl.us
Thomas Byron
Florida Department of Transportation, Materials Research Park, 5007 N.W. 39th Avenue, Gainesville, FL 32609
Phone: 352-955-6314, Fax: 352-955-6345, E-mail: tom.byron@dot.state.fl.us
ABSTRACT
The rutting performance of unmodified and SBS-modified Superpave mixtures was evaluated
using a Heavy Vehicle Simulator (HVS). Three different pavement designs were evaluated,
namely (1) two 2-inch lifts of unmodified mixture, (2) two 2-inch lifts of SBS-modified mixture,
and (3) a 2-inch lift of SBSmodified mixture over a 2-inch lift of unmodified mixture.
Laboratory tests were also conducted on asphalt mixture samples collected from the plant and
cored from the test pavements to evaluate the relationship between mixture properties and rutting
performance. Results from the HVS tests showed that the pavement sections with two lifts of
SBS-modified mixture clearly outperformed those with two lifts of unmodified mixture, which
had two to two and a half times the rut rate. The pavement sections with a lift of SBS-modified
mixture over a lift of unmodified mixture had only about 20% higher rutting than those with two
lifts of modified mixture when tested at 50 C. The test section with two lifts of SBS-modified
mixture and tested at 65 C still outperformed the test sections with two lifts of unmodified
mixture and tested at 50C. Mixtures with a higher rut depth in the APA also rutted more in the
HVS tests. Mixtures with a GSI of more than 1.0 as measured by the GTM rutted more than one
with a GSI close to 1.0. Rutting of the unmodified mixture was observed to be caused by a
combination of densification and shoving, while that of the SBS-modified mixture was due
primarily to densification.
Back to Table of Contents
Performance-Related Tests and Specifications for Cold In-Place Recycling: Lab and Field
Experience
Todd Thomas
Koch Pavement Solutions
4027 E. 37th St. North
Wichita, KS 67220
telephone 316/828-6737
fax 316/828-7385
thomast@kochind.com
Arlis Kadrmas
Koch Pavement Solutions
4027 E. 37th St. North
Wichita, KS 67220
telephone 316/828-8994
fax 316/828-7385
kadrmasa@kochind.com
ABSTRACT
Cold in-place recycling (CIR) is a cost-effective treatment for deteriorated pavements, and a
recent FHWA policy statement recommends recycled materials be considered for all paving
projects. A survey of 38 state departments of transportation by the Rocky Mountain User
Producer Group found that many routinely use the technique, but there are some problems with
performance reliability, specifically pointing to the lack of a uniform, defined design procedure,
and problems with raveling, thermal cracking, compaction problems, low early strength and
extended curing time. Other agencies are reluctant to try CIR because of those problems. Much
recent asphalt research focuses on lessening risks of early pavement failures through the use of
performance type specifications. When an improved technology for emulsion cold in-place
recycling was developed, researchers also developed performance-related test methods to
improve the reliability of the process and give agencies more confidence in trying CIR. A
laboratory raveling test run on Superpave Gyratory Compactor prepared samples simulates the
raveling that can occur on the newly recycled pavement, and is used as part of an engineered
design process as well as specifying raveling resistance and early strength. The Indirect Tensile
Test developed for Superpave design is modified to design and specify CIR resistance to thermal
cracking. The data from these tests for numerous projects is given, and compared for a side-byside trial of the new CIR and conventional methods. Since 2000, over 1280 lane-kilometers of
pavements in 17 states have been successfully recycled using the new performance-related
specifications.
Key Words: Cold In-Pace Recycling, Indirect Tensile Test, Raveling Test, Performance-Related
Specifications
Back to Table of Contents
Thermal Aspect of Frost-Thaw Pavement Dimensioning: In Situ Measurement and
Numerical Modeling
Michel Boutonnet, ing.
Denis Saint-Laurent, ing., M.Sc.
Laboratoire Central des Ponts et Chaussées
5 rue Phisalix
25 000 Besançon, France
Phone number : (33-1)-06 75 80 42 01
Email : mboutonnet@hotmail.com
Ministère des Transports du Québec
Direction du Laboratoire des chaussées, Service des
chaussées
930, Chemin Sainte-Foy, 5e étage
Québec, Canada G1S 4X9
Phone number: 418-643-7740
Fax number: 418-646-6195
Email: destlaurent@mtq.gouv.qc.ca
Patrick Lerat, ing., M. Sc, Ph D.
(corresponding author)
Laboratoire Central des Ponts et Chaussées
LAMI, Ecole Nationale des Ponts et Chaussées
6 et 8, Avenue Blaise Pascal, Cité Descartes, Champs
sur Marne
77 455 Marne la Vallée Cedex 2, France
Phone number : (33-1) 64 15 37 03
Fax number : (33-1) 64 15 37 41
Email : patrick.lerat@lami.enpc.fr
Yves Savard, ing., M.Sc.
Ministère des Transports du Québec
Direction du Laboratoire des chaussées, Service des
chaussées
930, Chemin Sainte-Foy, 5e étage
Québec, Canada G1S 4X9
Phone number: 418-643-8005
Fax number: 418-646-6195
Email: ysavard@mtq.gouv.qc.ca
ABSTRACT
The thermal behavior of pavements in winter has a major influence on their dimensioning. The
Paris-based Laboratoire Central des Ponts et Chaussées (LCPC) and the ministère des Transports
du Québec (MTQ) have models to forecast the propagation of frost, frost heave and thaw
phenomena. They have developed a collaborative project to validate these models on an
experimental pavement. This pavement was constructed in Québec in 1998 and its thermal
behavior was monitored for three years. Pavements with a cement treated base and a hot-mix
asphalt pavement were selected. Two test beds of each type were constructed. One of these two test
beds was thermally insulated by a layer of extruded polystyrene, while the second was not. This
paper presents the assessments of the SSR, GEL1D and CESAR – GELS thermal models. It
describes: - the models, - the site and the temperature conditions of the three winters, - the
pavement structures and their physical properties, - the instrumentation set up, - the analysis and
comparison of the results of the models among themselves and in relation to the observations
conducted on the pavements. This work shows that the models used provide a satisfactory
estimate of frost penetrations, with less than 10% deviation observed between the measured and
calculated depths. The deviations between the results of the different models are explained by the
differences between the modeling principles. The size and quality of the database constituted
under this project will make it possible to improve the thermal forecasting models through more
in-depth studies.
Back to Table of Contents
Design And Construction Of Rock Cap Roadways – A Case Study In Northeast
Washington
Jeff S. Uhlmeyer
Pavement Design Engineer
Washington State Department of Transportation
P.O. Box 47365
Olympia, WA 98504-7365
Phone: (360) 709-5485
Fax: (360) 709-5588
uhlmeyj@wsdot.wa.gov
James S. Lovejoy
Pavement Soils Testing Engineer
Washington State Department of Transportation
P.O. Box 47365
Olympia, WA 98504-7365
Phone: (360) 709-5477
Fax: (360) 709-5588
lovejoj@wsdot.wa.gov
Joe P. Mahoney
Professor
Civil and Environmental Engineering
University of Washington
Box 352700
Seattle, WA 98195-2700
Phone: (206) 685-1760
Fax: (206) 543-1543
jmahoney@u.washington.edu
Linda M. Pierce
State Pavement Engineer
Washington State Department of Transportation
P.O. Box 47365
Olympia, WA 98504-7365
Phone: (360) 709-5470
Fax: (360) 709-5588
piercel@wsdot.wa.gov
Mike R. Gribner
North/South Corridor Project Engineer
Washington State Department of Transportation
2714 N. Mayfair Street
Spokane, WA 99207-2090
Phone: (509) 324-6095
Fax: (509) 324-6099
gribnem@wsdot.wa.gov
Gordon D. Olson
Project Engineer
Washington State Department of Transportation
North 12223 Division
Spokane, WA 99218
Phone: (509) 324-6232
Fax: (509) 324-6234
olsongd@wsdot.wa.
ABSTRACT
In recent years the Washington State Department of Transportation (WSDOT) has deviated from
its normal policy of correcting frost heaving and thawing problems on state highways. WSDOT’s
traditional approach for frost design rehabilitation has been to place crushed stone base at least
half the depth of the frost penetration. This approach has served WSDOT well on the majority of
its highway system, however, other measures were sought to mitigate extensive frost related
problems in northeast Washington. To isolate the flow of water from the pavement structure, a
capillary break using a free draining aggregate or “rock cap” layer was used on projects during
the last five years. The rock cap material used was a 75 mm (3 in.) maximum sized material with
0 to 15 percent passing a 12.5 mm (1/2 in.) sieve. The open graded nature of the rock cap
provides a positive drainage blanket so that excess water can be eliminated from the roadway
structure thus eliminating frost heaving and thaw weakening problems. However, constructing
with a large stone material presents special construction considerations particularly pertaining to
the stability of the material. WSDOT’s construction experience is detailed in this study as well as
a summary of rock cap performance in Washington State.
Back to Table of Contents
Using Gyratory Compaction to Investigate Density and Mechanical Properties of RCC
Nader Amer, Research Assistant
Department of Civil and Environmental Engineering, The University of Alabama at
Birmingham, 1075 13th Street South (Hoehn Building), Suite 120, Birmingham, AL 35294-4440
Phone (205) 934-1574, Fax: (205) 934-9855, email: amern84@eng.uab.edu
Norbert Delatte, Associate Professor (Corresponding Author)
Department of Civil and Environmental Engineering, The University of Alabama at
Birmingham, 1075 13th Street South (Hoehn Building), Suite 120, Birmingham, AL 35294-4440
Phone (205) 934-8436, Fax: (205) 934-9855, email: ndelatte@uab.edu
Chris Storey, Research Assistant
Department of Civil and Environmental Engineering, The University of Alabama at
Birmingham, 1075 13th Street South (Hoehn Building), Suite 120, Birmingham, AL 35294-4440
Phone (205) 934-1574, Fax: (205) 934-9855, email: storec00@eng.uab.edu
Abstract:
Roller compacted concrete (RCC) is a durable, economical, low-maintenance material for low
speed heavy duty paving applications, including industrial and multimodal pavements. However,
it is difficult to prepare laboratory specimens to represent field performance because RCC is very
dry and requires considerable compactive effort to achieve field densities. The gyratory
compactor commonly used to prepare hot mix asphalt specimens may be used preparing
specimens for laboratory testing. Materials and mix designs from two industrial paving projects
were used to prepare specimens for comparison. Field results indicated that the gyratory
compactor produced specimens with mechanical properties consistent with those achieved in the
field. Specimens had high strength results and consistent density with low variability. The
gyratory compactor may be used to replace other methods presently used for preparing RCC
specimens such as the modified Vebe apparatus, the vibrating table and the vibrating hammer.
These methods have limitations that may be overcome with the gyratory compactor because of
its consistency of results and its compatibility with field results. The effects of density and
specimen aspect ratio on compressive and splitting tensile strength were investigated. The
number of gyrations applied to the specimen may be used to duplicate the desired field density.
For the industrial pavements investigated, approximately 60 gyrations accurately replicated field
conditions.
Back to Table of Contents
The Change to End-Result Specifications: Where Are We Now?
Alex Cervera, E.I.
University of Florida
P.O. Box 116580
Gainesville, FL 32611-6580
Ph: 352-846-0521, fax: 352-335-6548
alexcervera@hotmail.com
R. Edward Minchin Jr., Ph.D., P.E.
University of Florida
P.O. Box 116580
Gainesville, FL 32611-6580
Ph: 352-392-8173, fax: 352-335-6548
minch@ufl.edu
ABSTRACT
This paper discusses a recently conducted study that analyzes the prevalence of method
specifications versus end-result specifications in highway and bridge construction. The
definitions for both are stated, and the paper discusses the trend within the government and
industry to move away from method specifications and shift the systems in place for construction
contracting to more end-result specifications. A system for service contracting called
Performance-Based Service Contracting (PBSC) is in place and can be very useful as a guide.
The Federal Acquisition Regulation (FAR) is a document defined in this paper that provides the
criteria needed for a contract to be considered PBSC. Several government agencies, including the
U.S. Department of Transportation (DOT), have made the shift to performance-based
specifications a priority. The study thoroughly examined Standard Specifications for Highway
Construction from seven state DOTs and the Federal Standard Specifications for Highway
Construction; it also analyzed one state’s specifications for airport construction. The objective of
this study was to identify, within several standard specification books, those requirements that
can be considered method specifications and to classify and evaluate those requirements. Besides
reporting on the results of this primary focus, this paper also identifies trends among the
specifications reviewed. Specifically, the researchers identify trends regarding what states rely
the most heavily on method specs and which areas of construction are most likely to rely on
method specifications.
Back to Table of Contents
Detection of Surface Segregation using LASER
Jay N. Meegoda1, Geoffrey M. Rowe2, Andris Jumikis3, Chamil H. Hettiarachchi1,
Nishantha Bandara2 and Nicholas Gephart3
1New Jersey Institute of Technology, Civil & Env. Engineering, Newark, NJ 07102
2Abatech, Inc. 73 Old Dublin Pike, #312, Doylestown, PA 18901
3New Jersey Dept. of Transportation, Pavement Management Division, Trenton, NJ
ABSTRACT
This paper describes the research funded by New Jersey Department of Transportation to
develop a basis for an automated technology to quantify segregation that occurs during
construction of hot mix asphalt concrete pavements. A laser-based system was used for detection
of surface segregation. Two segregated test sections and a control test section were tested to
evaluate the applicability of laser texture method to detect and quantify segregation. Laser
texture data were gathered from all three sites, and sand patch and nuclear density tests were
performed at every 25 ft intervals of three sections. In addition to the above, visual surveys were
performed to confirm the measurements. Based on the test results it was found that the nuclear
density test could not be used to detect segregation but it can be used as a confirmation test. The
laser texture data showed the presence of segregation by consistently repeated texture peaks that
occurred at approximately 100-foot intervals. Test results from the control section were used to
establish a correlation between sand patch test (a quantitative test to determine segregation) and
laser texture data. This correlation will be used to calibrate laser texture data to quantify surface
segregation of asphalt pavements.
Key Words: Correlation, Surface Texture, Segregation, Measurement, Air Voids, Nuclear
Density, LASER (Light Amplification by Stimulated Emission of Radiation), Sand Patch and
Asphalt Pavements
Back to Table of Contents
Evaluation of Different Parameters for Superpave High Temperature Binder Specification
Based on Rutting Performance in the Accelerated Loading Facility at FHWA.
Raj Dongré, Ph. D.
Consultant, Federal Highway Administration
6300 Georgetown Pike, McLean, VA-22101
(703) 395-8854
rajdongre@yahoo.com
John D’Angelo, P. E.
Federal Highway Administration
400 Seventh Street, NW
Washington, D.C. 20590
(202) 366-0121
John.D’Angelo@fhwa.dot.gov
ABSTRACT
Various parameters have been proposed in recent literature to refine the current Superpave high
temperature binder specification. One parameter relates the phase angle directly to accumulated
strain from the creep recovery test. Another variation suggests a formula to predict the
accumulated strain using the current Superpave parameters G* and Sin(ä). Recently, NCHRP 910 project concluded by suggesting a criterion based on parameter derived from Burger’s
viscoelastic model. In Europe, zero-shear viscosity is being proposed as a high temperature
specification parameter. This paper evaluates these and other criteria proposed for high
temperature specification by examining the correlation of each criterion to pavement
performance. The experiment design consists of five asphalt binders used in the Federal
Highway Administration’s Accelerated Loading Facility (FHWA ALF). Additionally, two
binders used by Nevada Department of Transportation (DOT) in construction of highway I-80
test sections were also tested. Results show that the zero-shear viscosity correlates reasonably
well with performance and is the best parameter among all evaluated. However, accurate
determination of the zero-shear viscosity is time consuming and requires expensive
instrumentation making it unsuitable as a specification parameter. So, an easy method of
obtaining zero-shear viscosity was evaluated and found to correlate to performance equally well.
In this method, data from a single frequency sweep at the specification temperature is used to
estimate the zero-shear viscosity. This method can be implemented immediately.
Back to Table of Contents
A Fatigue Endurance Limit for Highway and Airport Pavements
Samuel H. Carpenter
Civil and Environmental Engineering Department
University of Illinois at Urbana-Champaign
1206 Newmark CE Lab
205 N. Mathews Avenue
Urbana, IL 61801
(217) 333-4188
scarpent@ux1.cso.uiuc.edu
Khalid A. Ghuzlan
California Department of Transportation (Caltrans) District 4
9th Floor / Design North Counties
111 Grand Ave. 94612
Oakland, CA 94623-0660
(510)-622-8652
kghuzlan@dot.ca.gov
Shihui Shen
Civil and Environmental Engineering Department
University of Illinois at Urbana-Champaign
1206 Newmark CE Lab
205 N. Mathews Avenue
Urbana, IL 61801
(217) 244-6064
ABSTRACT
The existence of a fatigue endurance limit has been postulated for a considerable time. With the
increasing emphasis on Extended Life Hot Mix Asphalt Pavements (ELHMAP), or perpetual
pavements (PP) the verification of the existence of this endurance limit, a strain below which
none or very little fatigue damage develops, has become a substantial consideration in the design
of these new multi-layered full depth pavements. This paper presents fatigue data collected on a
surface and binder mixture that were tested for an extended period from 5 to 48 million load
repetitions at strain levels down to 70 micro strain. The fatigue results are analyzed in the
traditional manner, and using the dissipated energy ratio (DER). This analysis shows that there is
a difference in the data at normal strain levels recommended for fatigue testing and at the low
strain levels. This difference cannot substantiate an endurance limit using traditional analyses
procedures, but the dissipated energy approach clearly shows that there is a distinct change in
material behavior at low flexural strain levels that supports the fact that at low strain levels the
damage accumulated from each load cycle is disproportionately less than what is predicted from
extrapolations of normal strain level fatigue testing which may be attributed to the healing
process. The conclusion of this study is that lab testing can verify the existence of a fatigue
endurance limit in the range of 90 to 70 micro strain, below which the fatigue life of the mixture
is significantly extended relative to normal design considerations.
Key Words: Fatigue, Dissipated Energy, Endurance Limit, Healing, Low-Strain
Back to Table of Contents
Ground-Penetrating Radar: What Can It Tell about the Moisture Content of the Hot Mix
Asphalt Pavement?
Lanbo Liu1, 2
1Department
of Geology and Geophysics
University of Connecticut
354 Mansfield Road, U-2045
Storrs, CT 06269-2045
phone: 860-486-1388 fax: 860-486-1383, e-mail: Lanbo.liu@uconn.edu
2Snow and Ice Branch, Cold Regions Research and Engineering Laboratory
Engineering Research and Development Center
US Army Corps of Engineers
72 Lyme Road
Hanover, NH 03755-1290
ABSTRACT
Laboratory experiments using ground-penetrating radar (GPR) on hot mix asphalt (HMA)
specimens were conducted under controlled condition of dry (freshly made), water-saturated, and
frozen conditions to measure the variations of electromagnetic (EM) wave velocity. The
purposes of measuring EM wave propagation velocity are calculating the dielectric constant and
the moisture content in the HMA pavement. GPR surveys were also repeatedly carried out on a
paved road segment with (HMA) on the University of Connecticut’s Depot Campus over a
complete seasonal cycle. The same 1-GHz antenna was used to acquire both laboratory and field
data. Results of the laboratory experiments serve as the baseline for interpreting field data. For
example, based on laboratory experiments, the complex refraction index model (CRIM) predicts
that when saturation changes from 0% (dry) to 90%, the EM velocity propagating through the
HMA specimen with 4% void ratio can drop about 12%. In the field data, the relative velocity
changes associated with rainwater wetting in the HMA can be up to 3-5%. This corresponds to 23 sample intervals’ change in GPR travel times. By applying the Topp model, this range in
velocity variation suggests a moisture change of 0.8-1.4%, and corresponds to the saturation
change of 10-20% in an HMA with 7% void ratio.
Back to Table of Contents
Successful Application of GPR for Quality Assurance/Quality Control of New Pavements
Imad L. Al-Qadi
Charles E. Via, Jr. Professor of Civil and Environmental Engineering,
Leader of the Roadway Infrastructure Group
Virginia Tech Transportation Institute
200 Patton Hall
Virginia Tech
Blacksburg, VA 24061-0105
Tel: 540 231-5262, Fax: 540 231-7532
e-mail: alqadi@vt.edu
Samer Lahouar
Graduate Research Assistant
Virginia Tech Transportation Institute
3500 Transportation Research Plaza
Virginia Tech
Blacksburg, VA 24061-0536
Tel: 540 231-1588, Fax: 540 231-1555
e-mail: slahouar@vt.edu
Amara Loulizi
Research Scientist
Virginia Tech Transportation Institute
3500 Transportation Research Plaza
Virginia Tech
Blacksburg, VA 24061-0536
Tel: 540 231-1504, Fax: 540 231-1555
e-mail: amlouliz@vt.edu
ABSTRACT
This paper presents the successful application of ground penetrating radar (GPR) as a quality
assurance/quality control tool to measure the layer thicknesses of newly built pavement systems.
This study was conducted on a newly built test section of Route 288 located near Richmond,
Virginia. The test section is a three-lane, 370m-long flexible pavement system composed of a
granular base layer and three different hot-mix asphalt (HMA) lifts. Ground penetrating radar
surveys were conducted on each lift of the HMA layers after they were constructed. To estimate
the layer thicknesses, GPR data was analyzed using simplified equations in the time domain. The
accuracy of the GPR system results was checked by comparing the GPR predicted thicknesses to
thicknesses measured directly on a large number of cores taken from the different HMA lifts.
This comparison revealed a mean thickness error of 2.9% for HMA layers ranging between
100mm (4in) and 250mm (10in) in thickness. This error is similar to the one obtained from direct
measurement of core thickness.
Keywords: quality assurance/quality control, ground penetrating radar, flexible pavement
Back to Table of Contents
Development and Implementation of a Continuous Vertical Track Support Testing
Technique
Dingqing Li
Transportation Technology Center, Inc. (TTCI)
55500 DOT Road
Pueblo, Colorado, 81001
Phone: (719) 584-0740 Fax: (719) 584-0791
E-mail: dingqing_li@ttci.aar.com - Corresponding Author
Randy Thompson
Transportation Technology Center, Inc. (TTCI)
Phone: (719) 584-0753 Fax: (719) 584-0770
E-mail:randy_thompson@ttci.aar.com
Previn Marquez
Transportation Technology Center, Inc. (TTCI)
Phone: (719) 584-0820, Fax: (719) 584-0770
E-mail: previn_marquez@ttci.aar.com
Semih Kalay
Transportation Technology Center, Inc. (TTCI)
Phone: (719) 584-0717, Fax: (719) 584-0580
E-mail: semih_kalay@ttci.aar.com
ABSTRACT
As part of an Association of American Railroads (AAR) research program, the Transportation
Technology Center, Inc. (TTCI), a subsidiary of the AAR, has developed a new method using its
Track Loading Vehicle (TLV) to measure vertical track deflections under given vertical loads
while in motion. The technique was developed to identify weak track locations and to measure
the load carrying capacity of existing tracks in order to aid and prioritize track maintenance and
to improve railroad operational performance. This paper discusses the development and
implementation of this continuous vertical track support measurement technique. This technique
provides an in-motion and non-destructive means of testing vertical track support. Currently, this
newly developed TLV technique is being used in revenue service: 1) to identify large track
stiffness variations along the track, indicating lower track strength or abrupt transitional stiffness
changes; 2) to locate the source of lower strength due to ballast and subgrade conditions; and 3)
to assess the need for upgrades to accommodate higher operation speeds and/or heavier axle
loads. Extensive tests in revenue service have shown this TLV testing technique to be a viable
method to perform the above tasks successfully. In addition, this new test technique can be used
to improve the understanding of track strength degradation over time and to help direct limited
maintenance resources to track locations requiring near-term maintenance.
Back to Table of Contents
Direct Tension Tests – a Useful Tool to Study the Low Temperature Properties of Wax –
Containing Asphalt
Susanna Man Sze Ho, Beverly Klesken, and Ludo Zanzotto
Bituminous Materials Chair
University of Calgary
2500 University Drive NW
Calgary, Alberta T2N 1N4
CANADA
Phone: 403-220-8077 and 403-220-8918
Fax: 402-282-7026
smsho@ucalgary.ca
bklesken@ucalgary.ca
lzanzott@ucalgary.ca
ABSTRACT
The effect of wax on the low-temperature performance of asphalt has been of interests to
researchers. In this work, two paraffin waxes, a microcrystalline wax and a combination of all
three waxes were added to asphalt to study their effect on the low-temperature properties of
asphalt. The molecular weight distributions of the wax materials were studied. The direct tension
test (DTT) technique, the Superpave tests and the glass transition temperatures (Tg) from the
modulated differential scanning calorimetry (MDSC) were used to study asphalts doped with 3%
wax.
The molecular weight and polydispersity of wax materials and their effect on asphalt were
studied. With the results of the analysis of the DTT failure energy and secant modulus, paraffin
wax lowered the failure energy and increased the secant modulus (stiffness) of the asphalt.
Microcrystalline wax had almost no effect on the secant modulus and even slightly raised the
failure energy at test temperatures higher than the predicted critical cracking temperature
(Tcritical). However, this microcrystalline wax studied also caused a drop in the DTT failure stress
values after Tcritical leading to a higher Tcritical if the DTT failure stress values after the drop were
included. We found that asphalt doped with a combination of all three waxes, 1% each, having a
wider molecular weight distribution, had an effect of restoring the lowtemperature property of
wax-containing asphalt by lowering the DTT secant modulus and shifting the BBR thermal stress
curve to the low-temperature end.
Back to Table of Contents
Refinement Of New Generation Open-Graded Friction Course Mix Design
Donald E. Watson, P.E.
Research Engineer
E-mail: dwatson@eng.auburn.edu
Kathryn Ann Moore, P.E.
(Corresponding Author)
Graduate Research Assistant, Auburn University
E-mail: kamoore@eng.auburn.edu
Kevin Williams
Research Engineer
E-mail: willik1@eng.auburn.edu
L. Allen Cooley, Jr.
Manager Southeastern Superpave Center
E-mail: coolela@eng.auburn.edu
National Center for Asphalt Technology
277 Technology Parkway
Auburn, AL 36830
Phone: (334) 844-6228
Fax: (334) 844-6248
ABSTRACT
Open-Graded Friction Course (OGFC) has been used in the United States for over fifty years. In
2000, NCAT research led to a recommended mix design procedure for a New-Generation OpenGraded Friction Course, but the work involved only one aggregate source. Therefore, NCAT is
in the process of refining this design procedure to ensure that it is applicable to other aggregate
types used in surface mixes throughout the United States. The objectives of NCAT’s current
research are to refine and field validate the new-generation OGFC mix design procedure. This
work has led to several experiments that are included in this paper. Several objectives have been
identified which need to be addressed. Superpave technology and use of the Superpave gyratory
compactor (SGC) needs to be incorporated into the mix design procedure. The Cantabro test for
durability and resistance to stone loss needs to be adapted to SGC prepared specimens and
performance parameters established. The asphalt draindown test, AASHTO T 305-97, which was
developed for Stone Matrix Asphalt mixtures, needs to be evaluated for applicability to OGFC
mixtures as well. In addition, a method for effectively evaluating air void criteria needs to be
investigated. Based upon the research conducted in this study, 50 gyrations of the SGC were
selected as the design compactive effort during mix design. Also, the use of SGC prepared
samples during the Cantabro test appears to be a reasonable alternative to Marshall compacted
samples.
Keywords: Open-Graded Friction Course, Superpave Gyratory Compactor, draindown,
Cantabro, CoreLok, air voids, porosity.
Back to Table of Contents
Combining Traditional and Non-Traditional NDT Techniques to Evaluate Virginia’s
Interstate 81
Imad L. Al-Qadi
Charles E. Via, Jr. Professor of Civil and
Environmental Engineering,
Leader of the Roadway Infrastructure Group
Virginia Tech Transportation Institute,
200 Patton Hall
Virginia Tech
Blacksburg, VA 24061-0105
Tel: 540 231-5262, Fax: 540 231-7532
e-mail: alqadi@vt.edu
Trenton M. Clark
Pavement Design and Evaluation Program Engineer
Virginia Department of Transportation
1401 E. Broad Street
Richmond, VA 23219
Tel: 804 328-3129, Fax: 804 328-3136
e-mail: Trenton.Clark@VirginiaDOT.org
David T. Lee
Salem District Materials Engineer
Virginia Department of Transportation
731 Harrison Avenue
Salem, VA 24153
Tel: 540-387-5383, Fax: 540 387-5503
e-mail: David.Lee@VirginiaDOT.org
Samer Lahouar
Graduate Research Assistant
Virginia Tech Transportation Institute
3500 Transportation Research Plaza
Virginia Tech
Blacksburg, VA 24061-0536
Tel: 540 231-1588, Fax: 540 231-1555
e-mail: slahouar@vt.edu
Amara Loulizi
Research Scientist
Virginia Tech Transportation Institute
3500 Transportation Research Plaza
Virginia Tech
Blacksburg, VA 24061-0536
Tel: 540 231-1504, Fax: 540 231-1555
e-mail: amlouliz@vt.edu
ABSTRACT
With increasing traffic volumes and truck weights on Virginia’s Interstate 81, the entire corridor
will be rehabilitated and expanded to meet future demands. Initial construction estimates
included the complete reconstruction of I-81. This paper presents the methods employed by the
Virginia Department of Transportation (VDOT) to structurally evaluate approximately 108 lane
km (68 lane mi) of pavement using Falling Weight Deflectometer (FWD) testing, Ground
Penetrating Radar (GPR), and pavement coring in order to quantify reconstruction and
rehabilitation limits. The recommended rehabilitation design based on this study is also
presented. While pavement coring and FWD testing are not new evaluation techniques for
VDOT, the use of GPR to measure continuous changes in pavement layer thickness and to
identify areas of moisture in the pavement structure is. The FWD data and results were used to
divide the flexible pavement portion of the project into eleven sections and to assess the
structural capacity of the pavement. Material retrieved from pavement cores were used to verify
layer thickness and condition. The results of the GPR testing increased the accuracy of the FWD
analysis by providing accurate and continuous thickness data, located additional potential
problem areas, and assisted in the pavement rehabilitation design process. By combining the
FWD, core, and GPR results, VDOT was able to determine which segments of the project
require reconstruction and which segments require major rehabilitation; thus, saving millions of
future construction dollars.
Back to Table of Contents
Construction-Related Variability in Mat Density Due to Temperature Differentials
Kim A. Willoughby
Washington State Department of Transportation
P.O. Box 47365
Olympia, WA 98504-7365
Phone: (360) 709-5474
Fax: (360) 709-5588
willouk@wsdot.wa.gov
Jeff S. Uhlmeyer
Washington State Department of Transportation
P.O. Box 47365
Olympia, WA 98504-7365
Phone: (360) 709-5485
Fax: (360) 709-5588
uhlmeyj@wsdot.wa.gov
Joe P. Mahoney
Civil and Environmental Engineering
University of Washington
Box 352700
Seattle, WA 98195-2700
Phone: (206) 685-1760
Fax: (206) 543-1543
jmahoney@u.washington.edu
Keith W. Anderson
Washington State Department of Transportation
P.O. Box 47365
Olympia, WA 98504-7365
Phone: (360) 709-5405
Fax: (360) 709-5588
anderke@wsdot.wa.gov
Linda M. Pierce
Washington State Department of Transportation
P.O. Box 47365
Olympia, WA 98504-7365
Phone: (360) 709-5470
Fax: (360) 709-5588
piercel@wsdot.wa.gov
ABSTRACT
This paper is an extension of the work done in Washington State to examine the systematic
occurrence and variability in density. The focus will be on the extent of the pavement that is
affected by variable density due to temperature differentials and the fact that randomly based
testing does not identify the occurrence of cyclic density differentials. Temperature differentials
14oC (25oF) or greater generally cannot be compacted to the same level of density as the
surrounding mat and therefore lead to significant density differentials (increase in air voids of 2
percent or more). A cyclic pattern typically occurs, matching each delivered truckload of mix,
although temperature differentials can occur randomly or not at all, depending on the remixing
device. The largest extent of pavement affected is when no remixing occurs and temperature
differentials develop every truckload of hot-mix. These temperature differentials can cover the
entire width and affect up to 50 percent of the mat. If the delivered hot-mix is thoroughly
remixed prior to placement, temperature differentials are minimal. Although density will vary in
any paving operation, it was found that a uniform temperature mat greatly increases the ability to
achieve a uniform density. Because of this cyclic pattern of variable density, random sampling
for in-place density does not properly identify or quantify this problem. It is recommended that
temperature differential areas be determined during construction and excluded from the random
sampling used for acceptance testing. The issue of variable densities due to temperature
differences or aggregate segregation should be identified and eliminated at the start of the
project.
Back to Table of Contents
Effectiveness Of Lime In Hot Mix Asphalt Pavements
Peter E. Sebaaly1
Edgard Hitti2
Dean Weitzel3
Submitted for Publications and Presentation
82nd Annual Meeting of the Transportation Research Board
1. Professor, Department of Civil Engineering, University of Nevada, Reno, NV 89557
(775) 784-6565, Fax (775) 784-1429, e-mail: Sebaaly@unr.nevada.edu
2. Laboratory Manager, Pavements/Materials Program, University of Nevada, Reno, NV
89557, e-mail: Edgard@unr.edu
3. Chief materials Engineer, Nevada Department of Transportation, 1263 S. Stewart St.,
Carson City, NV 89712, e-mail: Dweitzel@dot.state.nv.us
ABSTRACT
The pavement community has recognized that moisture damage of hot mixed asphalt (HMA)
mixtures has been a serious problem since the early 1960s. Numerous additives have been
evaluated with the objective of reducing the potential of moisture damage in HMA mixtures.
Lime has been one of the most common additives used to reduce the potential of moisture
damage. The Nevada Department of Transportation (NDOT) has been using lime in HMA
mixtures since the mid 1980s. The objective of this research was to quantify the improvements in
pavement performance that have been realized through the addition of lime to HMA mixtures.
The program evaluated field samples and pavement performance data from untreated and
limetreated pavements. The properties of untreated and lime-treated mixtures from field projects
in the southern and north-western parts of Nevada indicated that lime treatment of Nevada’s
aggregates significantly improves the moisture sensitivity of HMA mixtures. The study showed
that limetreated HMA mixtures become significantly more resistant to multiple freeze-thaw than
the untreated mixtures. The long term pavement performance data indicated that under similar
environmental and traffic conditions, the lime-treated mixtures provided better performing
pavements with less requirements for maintenance and rehabilitation activities. The analysis of
the impact of lime on pavement life indicated that lime treatment extends the performance life of
HMA pavements by an average of 3 years. This represents an average increase of 38% in the
expected pavement life.
Back to Table of Contents
Eight-Year of Field Performance of A Secondary Road Incorporating Geosynthetics at The
Subgrade-Base Interface
Imad L. Al-Qadi (Corresponding Author)
Chair E. Via, Jr. Professor of Civil and Environmental Engineering
200 Patton Hall, Blacksburg, VA 24061-0105
Tel: 540 231-5262, Fax: 540 231-7532
email: alqadi@vt.edu
Alexander Kwasi Appea
Graduate Research Assistant
Virginia Tech Transportation Institute
3500 Transportation Research Plaza, Blacksburg, VA 24061-0536
email: aappea@vt.edu
ABSTRACT
In June 1994 a fully instrumented 150m long secondary road pavement was built in Bedford
County, Virginia. This pavement section was composed of nine individual segments of 15m
length each. The nine sections include three groups with aggregate base layer thicknesses of 100,
150, and 200mm. Three sections from each group were stabilized with geotextiles and three were
stabilized with geogrids at the base course-subgrade interface. The remaining the other three
sections were kept as control sections. As part of the structural analysis, deflection data
parameters such as the Base Damage Index and Surface Curvature Index calculated from Falling
Weight Deflectometer (FWD) data were analyzed with incorporated temperature correction from
the time of construction until October 2001. Performance criteria such as rutting measurements
were also collected over the whole period. A nonlinear exponential model was used to describe
the development of rutting versus cumulative equivalent standard axle loads (ESALs) for the
100mm base course. A linear elastic program incorporating constitutive material properties was
used to calculate vertical compressive stresses, which were used with FWD deflections to predict
rutting rates utilizing a mechanistic equation. Rutting rate results confirmed the separation
function of geosynthetics by preventing the migration of fines from the subgrade to the base
course layer. Rutting results, deflection data, and service life analysis showed that
geosynthetically stabilized sections significantly improved the performance of the 100mm base
course sections.
Keywords: Flexible pavement, FallingWeight Deflectometer, rutting, geosynthetics, service life
Back to Table of Contents
Expanded Asphalt Stabilization On The Trans-Canada Highway
Becca Lane, P. Eng.
Senior Pavement Design Engineer
Pavements and Foundations Section
Materials Engineering and Research Office
Ministry of Transportation Ontario
1201 Wilson Avenue,
Downsview, Ontario
Canada, M3M 1J8
Ph: (416) 235-3513
Fax: (416) 235-3919
becca.lane@mto.gov.on.ca
Tom Kazmierowski, P. Eng.
Manager, Pavements and Foundations Section
Materials Engineering and Research Office
Ministry of Transportation Ontario
1201 Wilson Avenue,
Downsview, Ontario
Canada, M3M 1J8
Ph: (416) 235-3512
Fax: (416) 235-3919
tom.kazmierowski@mto.gov.on.ca
ABSTRACT
The first Ministry of Transportation Ontario (MTO) contract using expanded or “foamed”
asphalt stabilization was constructed in 2001, on 22.5 km of the Trans-Canada Highway, north of
Sault Sainte Marie. This flexible pavement recycling technique was selected mainly because of a
lack of aggregate availability in the area. The existing hot mix asphalt (HMA) and granular base
were reclaimed in-place to a depth of 180 mm, graded and compacted. Expanded asphalt
stabilization was then carried out to a depth of 150 mm, graded and compacted to final profile.
The expanded asphalt operation proceeded well, providing a smooth, hard, uniform surface for
detour traffic. Following a minimum two-day curing period, the stabilized base was overlaid
with 80 mm HMA. Falling weight deflectometer (FWD) testing was carried out prior to and
following construction. Normalized deflections were compared and the structural capacity of
each pavement layer was evaluated by back-calculating the results. The expanded asphalt
stabilized base was found to have a resilient modulus of 1395 to 1645 MPa and a granular base
equivalency factor of 1.50 to 1.58. In the year following construction, an ARAN survey of the
highway found that the northbound lanes had a mean international roughness index (IRI) of 0.7
and a mean rut depth of 2.9 mm. The southbound lanes were found to have a mean IRI of 1.0 and
a mean rut depth of 2.8. These results support the visual assessment that the pavement is
performing well after its first year of service. This paper presents the innovative design and
construction details of this demonstration project and discusses quality assurance, FWD test
results and short term post-construction monitoring.
Back to Table of Contents
A Pavement Management Perspective On Integrating Preventive Maintenance Into A
Pavement Management System
Kathryn A. Zimmerman, P.E.
David G. Peshkin, P.E.
Applied Pavement Technology, Inc.
3001 Research Road, Suite C
Champaign, IL 61822
(217) 398-3977
kzimmerman@pavementsolutions.com
dpeshkin@pavementsolutions.com
ABSTRACT
Pavement preservation programs are being used by many transportation agencies to costeffectively manage their pavement assets. An important part of a preservation program is the use
of pavement preventive maintenance treatments to improve the functional condition of the
network and retard the overall rate of deterioration. Since preventive maintenance treatments are
relatively inexpensive in comparison to resurfacing or reconstruction projects, preventive
maintenance programs have been found to be a cost-effective means of meeting pavement
performance goals. A pavement management system is an important tool to support a pavement
preservation strategy. Pavement management systems support preservation programs by assisting
with the identification and prioritization of preventive maintenance needs, providing justification
for funding levels, and evaluating the long-term impacts of various preservation strategies. To
date, many agencies have operated their preventive maintenance activities in isolation from their
pavement management programs. However, the potential benefits of closer integration between
these two activities are extremely high. This paper introduces some of the changes that may be
expected within a transportation agency wishing to integrate preventive maintenance and
pavement management. Specifically, the paper addresses the following technical areas:
Condition surveys and condition index calculations
Pavement performance models
Treatment rules.
Program development
In addition to these technical areas, the paper discusses some of the institutional issues that must
be addressed to successfully integrate the two programs. Examples from state highway agencies
that have addressed some of these areas are provided to illustrate possible solutions.
KEYWORDS
Preventive maintenance, Pavement performance, Pavement management systems, Pavement
maintenance and rehabilitation, Pavement condition surveys
Back to Table of Contents
Representative Sampling For Construction Quality Control At The 2000 Ncat Pavement
Test Track
R. Buzz Powell (Test Track Manager)
The National Center for Asphalt Technology
277 Technology Parkway
Auburn, AL 36830
Phone: (334) 844-6228
Fax: (334) 844-6853
buzz@eng.auburn.edu
ABSTRACT
A 2.8 kilometer experimental test oval has been constructed near the campus of Auburn
University for the purpose of conducting research to extend the life of flexible pavements. Fortysix different experimental sections were installed at the facility, with materials and methods
unique to section sponsors imported from all over the United States to maximize the applicability
of results. A design lifetime of truck traffic is now being applied over a two-year period of time,
with pavement performance documented weekly. Sponsors typically compare the performance of
two or more sections constructed with different materials and/or methods to obtain information
that can be used to build future pavements with the greatest amount of rut resistance. In order to
generate meaningful results, the Track was built to stringent quality standards. Quality control
sampling and testing was utilized on research mixes plant-produced before and during paving
operations to protect the research interests of section sponsors. To insure the value of subsequent
laboratory test results, samples that were truly representative of the entire production run were
needed. Initially, elaborate and time consuming shovel sampling was planned as the primary
method of representative sample recovery; however, a robotic sampling device erected by the
contractor onsite provided an opportunity to objectively compare subsequent laboratory results
using samples that were recovered from production truckloads at the plant using both methods.
An Analysis of data collected during construction illustrates the increase in percent within limits
that could be expected from the robotic sampling device if similar methods are employed.
Keywords = Asphalt, Test Track, PWL, Robotic Sampling, QC
Back to Table of Contents
Field Study of the Influence of Shear Stiffness on Rutting of Asphalt Mixes
Wael Bekheet, Ph.D. Candidate
Pavement Engineer
Stantec Consulting
415 Lawrence Bell Drive
Amherst, NY 14221
Tel: (716) 632-0804
Fax: (716) 632-4808
E-mail: wbekheet@stantec.com
Said Easa, Ph.D., P.Eng., FCSCE
Professor and Chair
Department of Civil Engineering
Ryerson Polytechnic University
Toronto, Ontario, Canada, M5B 2K3
Tel: (416) 979-5345
Fax: (416) 979-5122
E-mail: saideasa@acs.ryerson.ca.
A.O. Abd ElHalim, Ph.D., P.Eng., FCSCE
Professor and Chair
Department of Civil and Environmental Engineering
Carleton University
Ottawa, Ontario, Canada, K1S 5B6
Tel: (613) 520-2600 X 5789
Fax: (613) 520-3951
E-mail: ahalim@ccs.carleton.ca.
Joseph Ponniah, Ph.D., P.Eng.
Principal Pavement Engineer
Ministry of Transportation
Toronto, Ontario, Canada
Tel: (416) 235-4677
Fax: (416) 235-3919
E-mail: joseph.ponniah@mto.gov.on.ca
ABSTRACT
Field and laboratory testing programs were set up to evaluate the in-situ shear properties of
asphalt concrete mixes using the newly developed In-Situ Shear Stiffness Testing (InSiSST™)
facility, versus the laboratory evaluation using the resilient modulus and torsion testing. An
LTPP SPS-9A test site, with six adjacent test sections, was selected for the experimental
program. The results of the testing program were correlated with the rutting of the test sections
over a four-year period. In this paper, the InSiSST™ facility is briefly introduced and the
interpretation of the data collected is presented. The experimental program and analysis
procedures are then outlined. ANOVA was used to test the significance of the results and a
bivariate analysis was used for correlating rutting (as a criterion variable) and the different
laboratory and field measured material properties (as predictor variables). Finally, a regression
analysis between the in-situ shear stiffness and pavement rutting is presented. The results of the
study showed that the in-situ shear stiffness had the highest correlation coefficient with rutting
rate, and might be a suitable measure to characterize the asphalt mixes and evaluate the rutting
potential of asphalt pavements. This important result should be useful to the pavement engineers
interested in the evaluation of rutting using a simple field measure.
Back to Table of Contents
Traditional Fatigue Analysis of Asphalt Concrete Mixtures
Khalid A. Ghuzlan1
California Department of Transportation (Caltrans)
Materials Engineering and Testing Services, Mail Station 5
5900 Folsom Blvd
Sacramento, CA 95819
(916)-227-5848
kghuzlan@dot.ca.gov
Samuel H. Carpenter
Civil and Environmental Engineering Department
University of Illinois at Urbana-Champaign
1206 Newmark CE Lab
205 N. Mathews Avenue
Urbana, IL 61801
(217) 333-4188
scarpent@ux1.cso.uiuc.edu
ABSTRACT
Fatigue cracking is the accumulation of damage under repeated load applications in an asphalt
pavement. Fatigue life is commonly defined as the number of load cycles to fail the asphalt
concrete at strain (stress) occurring at the bottom of the asphalt layer. This approach of studying
fatigue is known as the phenomenological or the S-N approach (Stress-Number of cycles to
failure). This paper focuses on the traditional fatigue analysis using the S-N approach. Factors
affecting fatigue response of asphalt concrete mixtures are investigated. The relation between the
fatigue coefficients K1 and K2 in the traditional fatigue formula is discussed with emphasis on
factors that may have effect on this relation. Furthermore, the K1- K2 relation obtained from this
study is compared with other studies. A large fatigue database of laboratory testing was
developed to achieve these goals. Flexural fatigue testing was performed on about 480 asphalt
concrete samples. Both modes of loading, controlled stress and controlled strain, and two testing
temperatures are considered in this study. Findings of this study show that there is a high
correlation between K1 and K2. The K1-K2 relation was found to be significantly affected by
mode of loading, testing temperature and asphalt content in the mixture. Recommendations are
made about the need for further study of the K1-K2 relation and factors affecting it. It was also
recommended to investigate the possibility of using a simple test to predict the fatigue response
of asphalt concrete mixtures.
Key Words: Traditional Fatigue Analysis, K1-K2 Relation, Asphalt Concrete Fatigue, S-N
Approach, Fatigue Life, Flexural Fatigue Testing.
Back to Table of Contents
Comparison Of Non-Destructive Testing Devices To Determine In Situ Properties Of
Asphalt Concrete Pavement Layers
Athar Saeed, Ph.D., P.E. (Corresponding Author)
Senior Pavement Engineer
ERES Consultants Division of
Applied Research Associates, Inc.
112 Monument Place
Vicksburg, MS 39180
Phone: (601) 629-6165
Fax: (601) 626-6169
asaeed@ara.com
Jim W. Hall, Jr., P.E., Ph.D.
Director of Pavement Engineering
ERES Consultants Division of
Applied Research Associates, Inc.
112 Monument Place
Vicksburg, MS 39180
Phone: (601) 629-6165
Fax: (601) 629-6169
jhall@ara.com
ABSTRACT
Many highway agencies use non-destructive testing (NDT) techniques for pavement evaluation.
These include the falling weight deflectometer (FWD), the road-rater, the Dynaflect, the seismic
pavement analyzer (SPA), the portable SPA (PSPA), the ground penetrating radar (GPR), and
the dynamic cone penetrometer (DCP). Experience has shown that these techniques may not
provide an accurate characterization of the in situ material properties of AC pavement layers.
NCHRP sponsored research to identify and develop methods for determining the in situ modulus
and thickness of asphalt concrete (AC) pavement layers and resurfacing of Portland cement
concrete (PCC) pavements that improve the reliability of NDT techniques. NDT data were
collected using the FWD, SPA, PSPA, GPR and DCP at ten test sites (selected to represent
typical pavement sections) in the winter and summer seasons. Data from the field tests were
processed according to established methodologies. Cores from these sites were obtained for
laboratory testing to determine certain physical and mechanical response parameters for use in
data interpretation. Laboratory tests were conducted to reconcile stiffness measured by field
techniques to a temperature and rate of loading characteristic of vehicular traffic. The laboratory
tests included the ultrasonic wave velocity method, mechanical tests (resilient modulus and the
uniaxial frequency sweep), and mixture property tests. Considering the state-of-the-practice of
all the NDT technologies evaluated, the FWD and GPR were the best combination to effectively
measure the AC modulus and thickness of thick AC over granular base. The SPA/PSPA also
provided AC moduli that compared well with FWD moduli.
Back to Table of Contents
Cost-Effectiveness of Joint and Crack Sealing
Chuanxin Fang1
Khaled A. Galal, Ph.D.2
David R. Ward, P.E.3
John E. Haddock, Ph.D., P.E.4
Tom Kuczek, Ph.D.5
1Graduate
Research Assistant, Purdue University, School of Civil Engineering, 1284 Civil Engineering Building,
West Lafayette, IN 47907-1284, Office: (765) 494-2214, Facsimile: (765) 496-1364, email:
fangc@ecn.purdue.edu
2Pavement and Materials Research Engineer, Indiana Department of Transportation, Research Division, 1205
Montgomery Street, P.O. Box 2279, West Lafayette, IN 47906, Office: (765) 463-1521, Facsimile: (765) 4971665, email: kgalal@indot.state.in.us
3Research Section Manager, Indiana Department of Transportation, Division of Research, 1205 Montgomery Street,
P.O. Box 2279, West Lafayette, IN 47906, Office: (765) 463-1521, Facsimile: (765) 497-1665, email:
dward@indot.state.in.us
4Assistant Professor, Purdue University, School of Civil Engineering, 1284 Civil Engineering Building, West
Lafayette, IN 47907-1284, Office: (765) 496-3996, Facsimile: (765) 496-1364, email: jhaddock@ecn.purdue.edu
5Professor, Purdue University, Statistics Department, 399 Mathematical Sciences Building, West Lafayette, IN
47907-1399, Office: (765) 494-6051, Facsimile: (765) 494-0588, email: kuczek@stat.purdue.edu
ABSTRACT
The sealing and resealing of joints and cracks in concrete, hot-mix asphalt, and composite
pavements is assumed to be an important component of pavement maintenance and restoration in
that if performed effectively and in a timely manner, it will help to reduce pavement
deterioration and thereby prolong pavement life. However, this practice has recently been
challenged by some research that indicates sealing may not be cost-effective. The Indiana
Department of Transportation currently spends approximately four million dollars annually to
accomplish joint and crack without any quantitative evidence to justify the expenditure. The
primary objective of this research was to investigate the cost-effectiveness of joint/crack sealing
in relation to pavement performance. A rigorous review of the literature, a survey of practice,
and the design and analysis of a field experiment were conducted to complete the objective. The
literature review considered over one hundred potential references on the topic of joint and crack
sealing. The survey of practice revealed that most agencies joint/crack sealing policies are based
on long standing policy rather than research. The statistical analyses of inservice pavements
indicate that there are no significant differences between sealed and unsealed sections over the
last two years. It is recommended the monitoring of the pavement sites be continued so that the
longer-term performance can be measured and additional conclusions drawn regarding the costeffectiveness of joint/crack sealing.
Back to Table of Contents
Crack Modeling Of Asphaltic Mixtures Considering Heterogeneity Of The Material
Jorge Barbosa Soares
Universidade Federal do Ceará
Campus do Pici, s/n – Bloco 703
Zip Code.: 60.455-760 - Fortaleza, Ceará – Brazil
(55)(85) 288-9572 – R 210
jsoares@det.ufc.br
Felipe Araújo Colares de Freitas
Universidade Federal do Ceará
Campus do Pici, s/n – Bloco 70.3
Zip Code.: 60.455-760 - Fortaleza, Ceará – Brazil
(55)(85) 288-9572 – R 236
freitas@det.ufc.br
David H. Allen
College of Engineering
University of Nebraska
Zip Code: 68588 – Lincoln, Nebraska – USA
(402) 472-3181
dhallen@unl.edu
ABSTRACT
Cracking in the asphaltic layer of pavement has been shown to be a major source of distress in
roadways. Previous studies in asphaltic mixture cracking have typically not considered the
material heterogeneity. This paper presents a numerical method of analysis, based on the theory
of fracture mechanics, in which the binder and the aggregates are treated as distinct materials.
The simulations performed are verified and calibrated from simple and conventional laboratory
tests. The study investigates crack evolution under monotonic loading, even though the method
outlined can be further developed for the investigation of asphalt mixture fatigue. The approach
discussed is part of a multiscale framework for pavement analysis, in which the damage due to
cracking in the local scale can be considered in a global analysis at the actual pavement scale.
Key Words: Asphalt, Mixture, Finite Elements, Fracture Mechanics, Cohesive Zone
Back to Table of Contents
Development Of An Asphalt Aging Procedure To Assess Long-Term Binder Performance
Pramitha Juristyarini, Richard R. Davison, Charles J. Glover*
Department Of Chemical Engineering And
The Texas Transportation Institute
Texas A&M University
College Station, Texas 77843-3122
(979) 845-3361
Fax (979) 845-6446
ABSTRACT
Asphalt oxidation is a major contributor to pavement failure. Previous studies have shown that
ductility at 15 °C correlates well with road cracking. Moreover, when the ductility decreased to
about 3 to 5 cm, road cracking began to occur. A linear correlation between log ductility at 15
°C, 1 cm/min and the dynamic shear rheometer (DSR) function, G’/(’/G’), at 15 °C, 0.005 rad/s
exists below a ductility of 10 cm. A ductility of about 3 cm corresponds to a DSR value of
approximately 0.003. Nine asphalts, including seven SHRP asphalts and two Texas asphalts,
were aged at elevated temperatures between 60 to 110 °C, and pressures ranging from 0.2 to 5
atm oxygen. The DSR functions for aged and unaged samples were obtained. It was found that
for all aging conditions AAF-1 was the first to reach the critical value of 0.003. Each aging
condition was ranked and calibrated against environmental room aging (60 °C, 1 atm air), used
to simulate road aging. PAV thin-film aging at 90 °C, 20 atm air for 32 hours best represented
environmental room aging.
Keywords: Asphalt Oxidation, Asphalt Aging Test, Asphalt Performance, PAVAging Test,
Asphalt Pavement Performance
Back to Table of Contents
Development of Flexible Pavement Performance Prediction Model Based On Pavement
Data
Shiou-San Kuo, Ph.D., P.E.
Department of Civil and Environmental Engineering
University of Central Florida
Orlando, Fl. 32816
Phone: (407) 823-2880
Fax: (407) 823-3315
Email: Kuo@mail.ucf.edu
Hesham S. Mahgoub, Ph.D.
Department of Civil and Environmental Engineering
University of Central Florida
Orlando, Fl. 32816
Phone: (407) 823-4826
Fax: (407) 823-3315
Email: hmahgoub@mail.ucf.edu
Lorrie L. Hoffman, Ph.D.
Department of Statistics
University of Central Florida
Orlando, Fl. 32816
Phone: (407) 823-5525
Email: hoffman@mail.ucf.edu
Fanzhen Kong, Graduate Research Assistant
Department of Civil & Environmental Engineering
University of Central Florida
Orlando, Fl. 32816
Paper submitted for presentation at the
Transportation Research Board
82nd Annual Meting
Washington, D.C. 2003
ABSTRACT
Successful pavement management system requires estimates or predications of future pavement
performance so that rational comparisons may be made among alternative courses of action. The
prediction model is used in preparing long - range budget to maintain the highway system at a
specified minimum performance level and to determine the consequences of future funding
levels. The aim of this study is to determine the projected rate of deterioration of pavement
segments in District 5, Florida. Data related to historical traffic, speed limit, rainfall,
temperature, work-mix, historical condition ratings, distress types, pavement thickness, age, and
most recent year-to-year rating decline were collected for pavements. One of the nine counties in
District 5 was selected as the pilot county. Based on the data of the pilot county, analysis was
made to determine the appropriate response variable and predictor variables in the prediction
model. Statistical tests and regression were performed in the determination of final predictor
variables. A prediction model was developed for the pilot county. Comparing the predicted
condition ratings with actual ones checked the validity of the pilot model. After the pilot model
was investigated and verified, the regression modeling approach was employed on all nine
counties in District 5. The proposed models include predictor variables such as current year
condition rating, slope of degradation of previous years, and current annual average daily traffic.
An estimated pavement remaining life based on the condition survey is also presented according
to the predictive condition rating.
Back to Table of Contents
Effects of Environmental Factors on Pavement Performance – The Initial Evaluation of the
LTPP SPS-8 Experiment
Goran Mladenovic, Y. “Jane” Jiang, and Michael Darter
ERES Consultants, A Division of Applied Research Associates, Inc.
9030 Red Branch Road, Suite 210
Columbia, MD 21045-2116
Tel. 410 997-6181
Fax 410 997-6413
gmladenovic@ara.com (corresponding author)
jjiang@ara.com
mdarter@ara.com
ABSTRACT
The Long Term Pavement Performance (LTPP) Specific Pavement Study Experiment 8 (SPS-8),
Study of Environmental Effects in the Absence of Heavy Loads, examines the effect of climatic
factors and subgrade soil types on both flexible and rigid pavement sections that are subjected to
very limited traffic. This study was the first investigation of this important LTPP experiment.
The distresses, initial roughness values, and roughness time trends on SPS-8 sections were
examined and analyzed in relation to environmental factors. SPS-8 sections currently show little
distress. The only distress that appears on a significant number of SPS-8 flexible sections is
longitudinal cracking outside of the wheel paths. Significantly more sections with non-wheel
path longitudinal cracking exist in wet-freeze zones and on active subgrades. Performance
comparisons were also made between SPS-8 sections and their heavily loaded counterparts: SPS1 and SPS-2 sections. Overall, the SPS-1 and SPS-2 sections were exhibiting higher amounts of
load-related distresses, such as rutting and fatigue cracking in asphalt concrete pavements and
joint faulting and transverse cracking in jointed plain concrete pavements. However, the nonload-related distresses (asphalt concrete transverse cracking and non-wheel path longitudinal
cracking) were similar for SPS-1, SPS-2, and SPS-8. The results presented in this paper will be
useful to future researchers and practitioners in studying environmental effects on pavements and
using this experiment for calibration and validation of mechanisticempirical design models.
Back to Table of Contents
Fatigue Life Prediction Of Asphalt Mixes Using Viscoelastic Material Properties
Hyun Jong Lee, Ph.D.
Assistant Professor
Department of Civil and Environmental Engineering
Sejong University
Gawngjingu, Seoul 210-702
Tel: 82-2-3408-3812
Fax: 82-2-3408-3332
e-mail: hlee@sejong.ac.kr
Y. Richard Kim, Ph.D., P.E. (Corresponding Author)
Professor
Department of Civil Engineering
North Carolina State University
Raleigh, NC 27605
Tel: 19-515-7758
Fax: 19-515-7908
e-mail: kim@eos.ncsu.edu
Seung Woo Lee, Ph.D.
Assistant Professor
Department of Civil Engineering
Kangnung National University
Tel: 82-33-640-2419
fax: 82-33-646-1391
e-mail: swl@kangnung.ac.kr
ABSTRACT
This paper presents a simplified fatigue model that can predict the fatigue life of asphalt mixes
using viscoelastic properties only. This fatigue model was originally developed using the
elasticviscoelastic correspondence principle and continuum damage mechanics, and was reduced
to a simple version that can predict fatigue life using viscoelastic properties only. Based on the
experimental study conducted on twelve different types of asphalt mixes, it was observed that the
fatigue behavior of asphalt mixes is affected by both the viscoelastic properties and fatigue
characteristics, but mostly by the viscoelastic properties. In addition, it was found that the
coefficient of conventional strain-based fatigue models could be expressed in terms of
viscoelastic material properties. In the verification study, the fatigue model was able to predict
the fatigue life of various types of mixes at the same level of prediction accuracy without
changing the model coefficients. The fatigue model was also able to accurately predict the
changes in the fatigue life of an asphalt mix due to the changes in the volumetric mix properties.
Back to Table of Contents
Field Evaluation of the Stiffness of Unbound Aggregate Base Layers in Inverted Flexible
Pavements
Ronald G. Terrell, Graduate Research Assistant
Civil Engineering Department, The University of Texas at Austin
Austin, Texas 78712, Tel: (512) 471-4929, Fax: (512) 471-6548
E-mail: terrellrg@efdsw.navfac.navy.mil
Brady R. Cox, Graduate Research Assistant
Civil Engineering Department, The University of Texas at Austin
Austin, Texas 78712, Tel: (512) 471-4929, Fax: (512) 471-6548
E-mail: brcox@mail.utexas.edu
Kenneth H. Stokoe, II, Jennie C. and Milton T. Graves Chair in Engineering
Department of Civil Engineering, The University of Texas at Austin
Austin, Texas 78712, Tel: (512) 471-4929, Fax: (512) 471-6548
E-mail: k.stokoe@mail.utexas.edu
John J. Allen, Associate Director, International Center for Aggregate Research
Department of Civil Engineering, The University of Texas at Austin
Austin, Texas 78712, Tel: (512) 232-2574, Fax: (512) 471-6548
E-mail: joeallen@uts.cc.utexas.edu
ABSTRACT
Unbound aggregate base layers in a quarry haul road in Georgia were characterized using
embedded sensors and in-situ seismic testing. Two sections of the road were constructed as
inverted pavements, one using a South African Roads Board method and the other using a
conventional Georgia Department of Transportation method. A third was constructed using a
traditional method. Miniaturized versions of traditional crosshole and downhole seismic tests
were conducted to determine the stiffness of each base layer. Horizontally propagating
compression and shear waves were measured under four different loading conditions to
determine Young’s moduli and Poisson’s ratios of the base. An increase in stiffness with an
increase in load was measured. Additionally, it was found that the Georgia and South Africa
sections had similar stiffness. Surprisingly, the traditional section was found to be somewhat
stiffer than the other sections. This higher stiffness is thought to be due to a prolonged period of
compaction prior to construction of the unbound aggregate base layer, essentially transforming
the traditional section into an inverted pavement. Using the vertical total normal stresses
computed from ILLI-PAVE, a value of 0.3 for the earth pressure coefficient was found to be
reasonable for this material in determining the radial total normal stresses. The radial effective
normal stresses were calculated from the radial total normal stresses and experimentally
determined pore-water pressures. Additionally, the negative pore-water pressures in the partially
saturated granular base had a significant impact on the stiffness of the unbound aggregate base
layer, especially under small load levels.
Back to Table of Contents
Laboratory Performance Testing For The NCAT Pavement Test Track
R. Buzz Powell (Test Track Manager
The National Center for Asphalt Technology
277 Technology Parkway
Auburn, AL 36830
Phone: (334) 844-6228
Fax: (334) 844-6853
buzz@eng.auburn.edu
ABSTRACT
An experimental facility has been constructed near the campus of Auburn University for the
purpose of conducting research to extend the life of flexible pavements. Experimental sections
on the 2.8 kilometer Pavement Test Track are cooperatively funded by external sponsors, most
commonly state DOT’s, with operation and research managed by the National Center for Asphalt
Technology (NCAT). Forty-six different flexible pavements were installed at the facility, each at
a length of 61 meters. Materials and methods unique to section sponsors were imported during
construction to maximize the applicability of results. A design lifetime of truck traffic is now
being applied over a two-year period of time, with field performance documented weekly.
Sponsors typically compare the performance of two or more sections constructed with different
materials and/or methods to obtain information that can be used to build future pavements with
the greatest amount of rut resistance. In addition to assessing alternatives for sponsors, NCAT is
responsible for guiding the overall effort in a direction that will address policy issues for the
highway industry as a whole. Specifically, laboratory methods that have the potential to predict
rutting when used before and during construction are being compared to field performance for
every experimental mix in order to recommend the most suitable method(s). Results from loaded
wheel testing are presented to encompass the empirical approach, while results from shear and
creep testing facilitate mechanistic analyses. The success of each method will ultimately be
measured by comparing laboratory performance to performance on the experimental roadway.
Back to Table of Contents
MMLS3 Testing at the NCAT Test Track
André de Fortier Smit
Research Fellow, Center for Transportation Research (CTR)
University of Texas at Austin
Suite 200, 3208 Red River, Austin, TX 78705-2650
Phone: (512) 506 5837, Fax: (512) 506 5839, asmit@dot.state.tx.us
Fred Hugo
Director, Institute for Transportation Technology (ITT)
University of Stellenbosch
Dept Civil Engineering, Private Bag X1, Matieland, 7602, South Africa
Phone: +27 21 808 4363, Fax: +27 21 808 4361, fhugo@sun.ac.za
Dale Rand
Branch Manager, Texas Department of Transportation (TxDOT)
Flexible Pavements Division
Cedar Park Campus, 9500 N Lake Creek Parkway, Austin, TX 78717
Phone: (512) 506 5836, Fax: (512) 506 5839, drand@dot.state.tx.us
Buzz Powell
Test Track Manager, National Center for Asphalt Technology (NCAT)
University of Auburn
277 Technology Parkway, Auburn, AL 36830
Phone: (334) 844 6857, Fax: (334) 844 6248, buzz@eng.auburn.edu
ABSTRACT
This paper reports on one-third scale Model Mobile Load Simulator (MMLS3) testing done at
the NCAT test track. Dry and wet heated MMLS3 tests were done on five sections. The rutting
performances of the sections under MMLS3 trafficking were compared to that under full-scale
trafficking (truck test sections). A synthesis of the research included evaluation of results from
laboratory tests done on cores taken from the MMLS3 test sections from within and outside
trafficked wheelpaths. Tests on the cores included wet and dry Hamburg wheel tracking, SST
frequency sweep and semi-circular bending (SCB) strength testing. Investigations included the
evaluation of full-scale rutting data, laboratory wheel tracking test results and climatic data
monitored on the track during fullscale trafficking. The project validated the rut prediction
approach developed to compare MMLS3 and full-scale rutting performance and indicated that
the MMLS3 may be used to estimate full-scale rutting at the track under specific conditions.
Distress due to wet trafficking was also quantified in terms of reduction of tensile strength as
measured by the SCB. Conclusions are drawn and recommendations made regarding MMLS3 as
well as continued full-scale testing at the track. Comparative full-scale rutting performance of the
track sections evaluated may be quantified and ranked in terms of the MMLS3 performance of
these sections.
Key Words: MMLS3, Rutting, Strength, Moisture damage, APT, SCB.
Back to Table of Contents
Paved Shoulders Adjacent to Concrete Pavements: Synthesis of Current Practices in the
Midwest
Samuel Owusu-Ababio, P.E.,
Assoc. Prof., Dept. of Civ. and Envir. Engr.
Univ. of Wisc., Platteville, WI, 53818
Phone: 608-342-1554 Fax: 608-342-1566 owusu@uwplatt.edu.
Robert L. Schmitt, P.E.,
Asst. Prof., Dept. of Civ. and Envir. Engr.
Univ. of Wisc., Platteville, WI, 53818
Phone: 608-342-1239 Fax: 608-342-1566 schmitro@uwplatt.edu.
Joakim Osthus
Research Asst, Dept. of Civ. and Envir. Engr.
Univ. of Wisc., Platteville, WI, 53818
Phone: 608-342-1543 Fax: 608-342-1566 joakimosthus@hotmail.com.
ABSTRACT
A survey of seven Midwestern states was conducted as part of a research study to develop an
improved methodology for the design and construction of paved shoulders adjacent to concrete
pavements in Wisconsin. This paper presents an analysis of the various elements associated with
current paved shoulder practices for concrete pavements as reported by the Midwestern states.
These elements include: policies and procedures for paved shoulder type selection, thickness
determination and construction practices, maintenance practices, and functional interaction
between maintenance staff and design and/or construction units in relation to shoulder
maintenance issues. The analysis revealed that there is considerable variation among the states
on the elements. There is, however, an apparent lack of formal shoulder maintenance programs
among the states. In addition, no formalized form of communication exists between maintenance
staff and design and/or construction functional units when it comes to shoulder maintenance.
Most state highway agencies (SHA) reported premature failures in both asphalt and concrete
shoulders adjacent to mainline concrete pavements.
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Performance Analysis of Ultra-thin Whitetopping Intersections on US-169
Julie M. Vandenbossche, Ph.D, P.E.
University of Pittsburgh
934 Benedum Hall
Pittsburgh, PA
(ph) 412.624.9879
(e-mail) jmv@engr.pitt.edu
ABSTRACT
The Minnesota Department of Transportation (Mn/DOT) constructed an ultra-thin whitetopping
(UTW) project at three consecutive intersections on US-169 at Elk River to gain more
experience in both the design and performance of ultra-thin whitetopping. Distinct cracking
patterns developed within each test section. The UTW test sections with a 1.2-m x 1.2-m (4-ft x
4-ft) joint pattern included corner breaks and transverse cracks. Corner breaks were the primary
distress in the test section with a 1.8-m x 1.8-m (6-ft x 6-ft) joint pattern, although very little
cracking was exhibited. The Mn/ROAD UTW test sections on I-94 allow comparisons to be
made of the same UTW design on HMA pavements with different structural capacities. The
strain and deflection measurements emphasize the importance of the support provided by the
HMA layer. A reduction in this support occurs when the temperature of the HMA is increased or
when the HMA begins to ravel. Cores should be pulled from the pavement when evaluating
whether UTW is a viable rehabilitation alternative to determine if the asphalt is stripping and if
the asphalt layer has adequate thickness. UTW can be successfully placed on as little as 76 mm
(3 in) of asphalt, if the quality of the asphalt is good. The cores should also reveal the asphalt
layer is of uniform thickness and stripping/raveling has not occurred. If these conditions exist,
UTW is a good option for rehabilitating asphalt pavements.
Key Words: thin whitetopping, whitetopping, repairs, rehabilitation, distresses, inlays
Back to Table of Contents
Performance In Fatigue Cracking Of High Strength Concrete As Ultra-Thin Whitetopping
José T. Balbo, Associate Professor
Laboratory of Pavements Mechanics
Escola Politécnica da Universidade de São Paulo
Cidade Universitária – São Paulo – SP
CEP 05508-900 Brasil
Phone: +55 11 3091-5306
Fax: +55 11 3091-5716
e-mail: jotbalbo@usp.br
ABSTRACT
Six experimental sections of UTW employing high strength concrete were monitored up to
failure during an accelerated experiment in highway truck lane. Characterization of existing
pavement properties and concrete parameters for mechanistic analysis comprised field and
laboratory tests. Major mode of degradation observed on UTW panels was the development of
corner and diamond cracks followed by faulting in cases of shorter slabs (less than one meter).
The field results analyzed through a mechanistic approach have allowed to define a
semiempirical model describing the fatigue damage for UTW sections taking 10% of corner
cracked panels as a threshold, resulting in a similar model to others formerly developed. The
experiment could emphasize the relevant role of the support k-value as well thickness and length
of slabs on the performance of UTW composite pavements.
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Performance of Flexible Pavement Maintenance Treatments in the LTPP SPS-3
Experiment
Kathleen T. Hall, Partner
ProTech Engineering
1271 Huntington Drive South
Mundelein, IL 60060
Phone 847-549-8410
Fax 847-589-4284
kthall64@earthlink.net
Carlos E. Correa, Partner
ProTech Engineering
Providencia 1998, Oficina 203
Providencia, Santiago, Chile
Phone and fax 56-2-335-9415
ccorrea@entelchile.net
Amy L. Simpson, Senior Engineer
LAW PCS
12104 Indian Creek Court, Suite A
Beltsville, MD 20705
301-210-5105
301-210-5032
Amy.Simpson@mactec.com
ABSTRACT
This paper presents the results of a study conducted to assess the relative performance of
different flexible pavement maintenance treatments, including the influence of pretreatment
condition and other factors. The data used in this study were drawn from the Long-Term
Pavement Performance Studies’ SPS-3 experiment. The maintenance treatments used in the SPS3 experiment are thin overlays, slurry seals, crack seals, and chip seals. The initial and long-term
effects of the maintenance treatments on International Roughness Index (IRI), rutting, and
cracking were analyzed, as well as the influence of time, truck traffic, pretreatment condition,and
climate. Thin overlays were found to be the most effective of the treatments studied, followed by
chip seals and slurry seals. Crack sealing did not demonstrate any beneficial initial or long-term
effect with respect to IRI, rutting, or cracking.
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Physico-Chemical Characterization of Asphalt-Aggregate Interactions under the Influence
of Freeze-Thaw Cycles
Shin-Che Huang
Western Research Institute
365 North 9th Street
Laramie, WY 82072-3380
Phone (307) 721-2221; Fax (307) 721-2345; E-mail: Shuang@uwyo.edu
Raymond E. Robertson
Western Research Institute
65 North 9th Street
Laramie, WY 82072-3380; Phone (307) 721-2221; Fax (307) 721-2345; E-mail: redoxwri@uwyo.edu
Jan F. Branthaver
9 Parkview Lane
Chatham, IL 62629
ABSTRACT
Experiments were conducted to investigate the impact of different freeze-thaw cycling on the
mechanical strength of eight different types of asphalt-aggregate mixtures. In these experiments,
cylindrical specimens prepared by gyratory compactor were subjected to different freeze-thaw
cycling. The indirect tensile strength at 25°C (77°F) was determined after different numbers of
freeze-thaw cycles. All broken samples were contacted with cyclohexane to elute asphalt from
the mixtures. Polar organic fractions were isolated from each of the mixtures using a solvent
extraction method. It was observed that mild oxidation of asphalt results in recovery of large
amounts (compared with unaged asphalts) of polar organics from the aggregate surface of all
mixtures. Presumably these strongly bonded materials are important factors in protecting
mixtures against the action of moisture. Test results also indicated that mixtures prepared from
asphalt, which had been pre-aged, resisted freeze-thaw action more than unaged asphalt, and
showed higher retained tensile strength than the unaged mixtures. In addition, results showed
that mixtures prepared from dodecanophenone-treated asphalt interact with aggregates
differently.
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Quantifying the Benefits of a Geocomposite Membrane as a Pavement Moisture Barrier
Using Ground Penetrating Radar and Falling Weight Deflectometer
Samer Lahouar
Mostafa Elseifi
Graduate Research Assistant
Virginia Tech Transportation Institute
3500 Transportation Research Plaza
Virginia Tech, Blacksburg, VA 24061-0536
Tel: 540 231-1588, Fax: 540 231-1555
e-mail: slahouar@vt.edu
Graduate Research Assistant
Virginia Tech Transportation Institute
3500 Transportation Research Plaza
Virginia Tech, Blacksburg, VA 24061-0536
Tel: 540 231-1568, Fax: 540 231-1555
e-mail: melseifi@vt.edu
Imad L. Al-Qadi
John A. Wilkes
Charles E. Via, Jr. Professor of Civil and
Environmental Engineering
Leader of the Roadway Infrastructure Group
Virginia Tech Transportation Institute
200 Patton Hall, Virginia Tech, Blacksburg, VA
24061-0105
Tel: 540 231-5262, Fax: 540 231-7532
e-mail: alqadi@vt.edu
President
CARPI USA
3517 Brandon Ave. Suite 100, Roanoke, VA 24018
Tel: 540-345-7582, Fax: 540-344-7154
e-mail: carpiwlks@aol.com
Amara Loulizi
Research Scientist
Virginia Tech Transportation Institute
3500 Transportation Research Plaza
Virginia Tech, Blacksburg, VA 24061-0536
Tel: 540 231-1504, Fax: 540 231-1555
e-mail: amlouliz@vt.edu
Thomas E. Freeman
Senior Research Scientist
Virginia Transportation Research Council
530 Edgemont Road, Charlottesville, VA 22903
Tel: (804) 293 1957, Fax: (804) 293 1990
e-mail: freemante@vdot.state.va.us
Virginia Tech Transportation Institute
Virginia Tech
Blacksburg, Virginia
ABSTRACT
The objective of this study is twofold: (1) quantify the benefits of a specially-designed
geocomposite membrane (a low modulus polyvinyl chloride [PVC] layer sandwiched between
two nonwoven geotextiles) to act as a moisture barrier in flexible pavement systems; and (2)
quantitatively measure moisture content of unbound granular materials nondestructively. The
geocomposite membrane was installed over half the length of a pavement test section at the
Virginia Smart Road, while the other half of the test section consisted of the same design without
the interlayer system. Air-coupled ground penetrating radar (GPR) system with 1 GHz frequency
bandwidth was used to monitor and detect the presence of moisture within the pavement system
over different periods corresponding to different levels of water accumulation. Results of GPR
data analysis indicated that the use of the geocomposite membrane reduced water infiltration to
the aggregate base layer by as much as 40% when measurements were performed after rain. It
was also found that the moisture content underneath the interlayer was almost constant and
therefore independent of the amount of rainwater, which is the primary source of moisture in
pavement systems that have a low water table. Impact of moisture in the granular layers is
investigated using the results of a deflection monitoring program. Results indicated that the area
with the geocomposite membrane always showed less deflection than the area without the
interlayer.
Keywords: geocomposite membrane, drainage, ground penetrating radar
Back to Table of Contents
Reinforcing Benefits of Geosynthetic Materials in Asphalt Concrete Overlays using Pseudo
Strain Damage Theory
Gregory S. Cleveland, P.E.
Texas Department of Transportation
125 E. 11th Street
Austin, Texas 78701-2483
Phone: (512) 506-5830
Fax: (512) 506-5839
Email: gclevela@dot.state.tx.us
Robert L. Lytton, Ph.D., P.E.
Texas Transportation Institute
The Texas A&M University System
3135 TAMU
College Station, TX 77843-3135
Phone: (979) 845-9964
Fax: (979) 845-0278
Email: r-lytton@tamu.edu
Joe W. Button, P.E.
Texas Transportation Institute
The Texas A&M University System
3135 TAMU
College Station, TX 77843-3135
Phone: (979) 845-9965
Fax: (979) 845-0278
Email: j-button@tamu.edu
ABSTRACT
Reflective cracking is one of the more serious distresses associated with existing hot mix asphalt
(HMA) or Portland concrete cement (PCC) pavements overlaid with a thin bituminous layer.
Preventive maintenance techniques have included incorporating geosynthetic materials, defined
herein as grids, fabrics, or composites, into the pavement structure. These materials have
exhibited varying degrees of success and their use within a particular agency has been based
primarily on local experience or a willingness to try a product that appears to have merit. The
research described herein was excerpted from a comprehensive research report of a project
sponsored by the Texas DOT. This paper describes the methodology used to compare the relative
effectiveness of six commercially available geosynthetic materials in reducing the severity or
delaying the appearance of reflective cracking in HMA overlay. Each geosynthetic material was
incorporated into compacted HMA specimens and testing to failure using a tensile fatigue-testing
machine called the TTI Overlay Tester. Engineering fracture mechanics and pseudo strain energy
concepts, based on the elastic-viscoelastic correspondence principle, were used and demonstrated
to be an appropriate and efficient method of characterizing the fatigue damage process. By
considering the effects of the geosynthetic products on the loading and unloading paths of the
HMA specimens, a new concept was developed and termed the Reinforcing Factor, R. The use
of this value allows the industry to characterize the relative reinforcing benefits of geosynthetic
materials in reducing reflective cracking in HMA overlays. The Crack Speed Index was then
derived to summarize the complex interactions of the material properties. In general, grids and
composites performed better than fabrics, which, in turn, performed better than a thin tacked
surface as compared to non-reinforced specimens. These findings indicate the acute sensitivity of
the TTI Overlay Tester, as well as the analysis procedures, in differentiating such minuet
differences as a thin tack coat. As a result of this investigation, design equations were developed
between the fracture properties of the geosynthetic-mixture system and the relaxation modulus
properties of the HMA. These equations can be used in forward calculating design methods to
predict the rate of crack growth and support the design of an HMA overlay to resist reflective
cracking. To calibrate the design equations, comparative field test pavements were constructed in
three regions of Texas (Amarillo, Waco, and McAllen) using each geosynthetic material. These
pavements are being monitored over the next 4 years with findings presented in a separate report.
Back to Table of Contents
A Simplified Overlay Design Model against Reflective Cracking Utilizing Service Life
Prediction
Mostafa M. Elseifi
Graduate Research Assistant
Virginia Tech Transportation Institute
3500 Transportation Research Plaza
Blacksburg, VA 24061
Email: melseifi@vt.edu
Phone: 540 231-1568; Fax: 540 231-1555
Imad L. Al-Qadi
Charles E. Via, Jr. Professor of Civil and Environmental Engineering
200 Patton Hall, Virginia Tech
Blacksburg, VA 24061
Email: alqadi@vt.edu
Phone: 540 231-5262; Fax: 540 231-7532
ABSTRACT
Although it is the major mode of failure in rehabilitated pavement structures, reflection of
cracking seldom has been considered in the overlay design process mainly due to its complexity.
This paper presents the development of an overlay design procedure to predict the service life of
rehabilitated flexible pavement structures against reflective cracking. A simple equation was
derived based on three-dimensional (3D) finite element (FE) models and by utilizing linear
elastic fracture mechanics (LEFM) principles. The FE models simulate a variety of rehabilitated
cracked pavement structures. A detailed sensitivity analysis was performed to establish the
accuracy of the FE models. Then, accurate simulation of the crack singularity was achieved by
modeling several contour integral evaluations along the crack front. Both crack initiation and
propagation phases were considered in the formulation. The crack initiation phase is described
using a traditional fatigue law developed by the Belgium Road Research Center, and the crack
propagation phase is described using Paris-Erdogan phenomenological law. Three contour lines
were used around the crack front to calculate the path-independent J-integral. Calculations of the
stress intensity factors based on the J-integral are presented. An example is presented to
demonstrate the use of the developed design equation in a routine overlay design. Keywords:
reflective cracking, finite element, fracture mechanics
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A Study On Properties Of Foamed Asphalt Treated Mixes
Chui-Te Chiu, Ph.D.
Chung Hua University, Department of Civil Engineering
No. 30 Tung Shiang, Hsin Chu, 300, Taiwan
Tel: (886-3)5186715. Fax: (886-3)5372188. ctc@chu.edu.tw
Ming-Yung Huang
Chung Hua University, Department of Civil Engineering
No. 30 Tung Shiang, Hsin Chu, 300, Taiwan. Tel: (886-3)5186715. Fax: (886-3)5372188
ABSTRACT
From both economical and ecological points of view, cold recycling is much more beneficial
than hot recycling. However, due not only to the intrinsic properties of binding mechanism but
also to the difficulties of process control, cold recycling did not gain common acceptance in
Taiwanese paving industries. Recently, the use of foamed asphalt in cold recycling has gained
more and more acceptance in Europe, South Africa, and Asia. For further developing
environment friendly paving materials and construction processes, this particular study is
performed to investigate the engineering properties of foamed asphalt treated base in Taiwan.
Using a laboratory foaming plant, works were performed on local materials to produce foamed
asphalt treated cold mixtures. The engineering properties of foamed asphalt treated mixes are
investigated and compared with those of hot recycled mix. Test results show the benefits of
utilizing high percentages (80%) of milled asphalt in foamed asphalt mixes. The optimum
asphalt content can be reduced from 3.5% to 2.0% compared to mixes consisting of all new
aggregate, and the moisture resistance of the mixture is enhanced. Resilience modulus and
fatigue data show that foamed asphalt treated mix performs as well as hot recycled mix.
Back to Table of Contents
A Validated Model For Predicting Field Performance Of Aggregate Base Courses
EROL TUTUMLUER
Associate Professor of Civil Engineering
University of Illinois at Urbana-Champaign
Urbana, Illinois, USA
Phone: 217/ 333-8637
Fax: 217/333-1924
tutumlue@uiuc.edu
DALLAS N. LITTLE
E.B. Snead Professor
Texas A&M University
Department of Civil Engineering
College Station, Texas
Phone: 979/845-9847
d-little@ ttimail.tamu.edu
SUNG-HEE KIM
Graduate Research Assistant
Department of Civil Engineering
Texas A&M University
College Station, Texas
Sung-Hee-Kim@ttimail.tamu.edu
ABSTRACT
The International Center for Aggregates Research (ICAR) Research Project 502 focused on
pavement layers of unbound aggregate proper representation in mechanistic pavement models. The
research team developed models for the resilient and permanent deformation behavior from the
results of triaxial tests conducted at the Texas Transportation Institute (TTI) and at the University of
Illinois. The studies indicate that the unbound aggregate base (UAB) material should be modeled as
nonlinear and cross-anisotropic to account for stress sensitivity and the significant differences
between vertical and horizontal moduli and Poisson’s ratios.
Field validation data were collected from a full-scale pavement test study conducted at
Georgia Tech. The validation of the anisotropic modeling approach was accomplished by analyzing
conventional flexible pavement test sections using the GT-PAVE finite element program to predict
responses to load in the UAB layer and comparing these predicted responses to the measured values.
Laboratory testing of the aggregate samples was conducted at the University of Illinois, and
characterization models were developed for the stress sensitive, cross-anisotropic aggregate behavior.
With nonlinear anisotropic modeling of the UAB, the resilient behavior of pavement test sections
was successfully predicted for a number of response variables. In addition, the stress sensitive, crossanisotropic representation of the base was shown to greatly reduce the horizontal tension computed
in the granular base when compared to a linear isotropic representation.
Key Words: Anisotropy, Unbound Aggregate, Base Course, Modeling, Field Performance
Back to Table of Contents
Defining Asphalt Binder Fatigue as a Function of Pavement Temperature and Pavement
Structure
Wilfung Martono
Hussain U. Bahia
The Asphalt Pavement Research Group
Department of Civil and Environmental Engineering
The University of Wisconsin – Madison
2210 Engineering Hall
1415 Engineering Dr.
Madison WI, 53706
(608) 265-4481
ABSTRACT
Fatigue damage is a distress mechanism observed in asphalt particularly at moderate to low temperatures.
One of the major challenges in the study of fatigue damage is the lack of definition of fatigue
failure that is consistent with the actual performance of the material regardless of testing
conditions. Based on recent development in measuring binder fatigue, binder fatigue data could be
analyzed using the dissipated energy ratio concept (DER) to estimate Np (number of cycles to crack
propagation). Initial Wi is calculated and used as the main independent variable to normalize different
testing conditions. The parameter Np20, which is defined as the number of cycles until dissipated energy
ratio is at 20% deviation from no-damage linear line has been introduced by the NCHRP 9-10 project as a
definition of failure that is independent of the loading mode. Recent studies however have raised
questions regarding the temperature and stiffness level at which true binder fatigue could be measured
with the DSR. It has been claimed that at stiffness level (G*) lower than 10-15 MPa the type of failure
observed is instability effected by edge effects rather than true fatigue. It is apparent that this opinion is
derived from illogical fatigue trends of binders as a function of temperature. This study was initiated to
examine what causes such illogical fatigue trends. Also the study attempts to explain the importance of
differentiating between temperature effect and modulus effect, and advocates the use of energy input as
the main fatigue law variable. A selected set of unmodified and modified asphalt binder were tested under
a range of loading modes, stress and strain amplitudes, temperatures and frequency to show how a typical
asphalt material performs along a range of Wi values. It is found that if the effect of temperature is
studied independent of the energy input, the illogical fatigue trends observed in other studies could be
explained. It is believed that fatigue occurs at high temperatures (low modulus value) and it follows the
same fatigue trends as that at high modulus value. Models are introduced which take into account effect
of temperature as another independent variable similar to energy input (Wi). Related to the subject of
using energy dissipated is ranking of binders with respect to their fatigue behavior as defined by fatigue
law. It is shown in this study that if strain or stress is used as the independent variable in the fatigue law,
the ranking of binders could be different than using Wi as the independent variable. Because it is very
difficult to decide if a pavement will operate under stress or strain conditions, it is suggested that ranking
be done based on the fatigue law using Wi. For binder fatigue, this study concludes with recommending
using fatigue law in which Np20 is expressed in terms of Wi at a given temperature but also presents
possibilities for modeling in terms of Wi and G*/sin(d) combined.
Key Words: Fatigue cracking, Modified asphalt binders, Temperature susceptibility, Dissipated energy
ratio, Time sweep test (DSR)
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Variation Of Pavement Smoothness Between Adjacent Lanes: Implications For
Performance Based Contracting
Charles E. Dougan, Ph.D., Research
Associate
Connecticut Transportation Institute
University of Connecticut
179 Middle Turnpike
Storrs, CT 06269-0202
860-486-5535
cdougan@engr.uconn.edu
Lisa Aultman-Hall, Associate Professor
Department of Civil and Environmental Engineering
University of Connecticut
261 Glenbrook Road
Storrs, CT 06269
860 486 2717
fax 486 2298
aultman@engr.uconn.edu
Soon-Nam Choi, Ph.D. Candidate
Department of Educational Psychology
249 Glenbrook Road
University of Connecticut
Storrs, CT 06269-2064
soc98001@uconn.edu
Bradley Overturf, Transportation Photolog
Supervisor
Connecticut Department of Transportation
Division of Materials and Research
280 West Street
Rocky Hill, CT 06067
860-258-0311
Bradley.Overturf@po.state.ct.us
Christine Hobson, Research Assistant
Department of Civil and Environmental Engineering
University of Connecticut
261 Glenbrook Road
Storrs, CT 06269
christine.hobson@uconn.edu
ABSTRACT
There is a need to understand how pavement smoothness varies over space and time and with
other environmental factors. This paper uses information from a large set of IRI field data
together with traffic and pavement design/age data to consider IRI variation across the lanes of
multilane highways and freeways in the state of Connecticut. The objective is to determine to
what extent IRI varies over all lanes through time in order to consider the amount of field data
that will have to be collected for DOTs to adequately measure or predict pavement rideability for
newer performance-based contracting agreements, particularly those involving contractor
warranties. Results indicate that based on IRI small average roughness differences exist between
adjacent lanes. IRI values are highest in the outer right lanes. Lateral differences are relatively
consistent and random, but small in magnitude. No strong relationships could be found between
pavement age, composition or traffic loading on IRI. However, some preliminary evidence
suggests that the influence of these factors may also vary by lane. These results have
implications for future research as well as the logistics of pavement monitoring by DOTs for
warranty based contract payments. Firstly, the difference in IRI between lanes is small and
consistent (0.1-0.2) when averaged over longer sections and therefore it is not necessary to repeat
measurements for all lanes along longer projects or whole routes. Secondly, the variation in
these field IRI measurements is unpredictable, especially over smaller spatial areas, suggesting
that IRI data should be collected in all lanes when shorter projects are being considered.
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