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Federal Highway Administration Research and Technology
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| This report is an archived publication and may contain dated technical, contact, and link information |
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Publication Number: FHWA-RD-02-042 Date: October 2000 |
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National Cooperative Highway Research Program by Kevin D. Stuart Walaa S. Mogawer, PhD, P.E. |
This report documents the effects of polymer-modified asphalt binders on the rutting resistance of a mixture with diabase aggregate. It is part of a research study titled "Understanding the Performance of Modified Asphalt Binders in Mixtures." This study is partially funded through National Cooperative Highway Research Program (NCHRP) Project 90-07. The objective of NCHRP Project 90-07 is to determine if asphalt binder performance is captured by the Superpave asphalt binder specification developed under the 1987 to 1993 Strategic Highway Research Program, with an emphasis on evaluating the performances of mixtures containing polymer-modified asphalt binders with identical Superpave performance grades, but varied chemistries. Asphalt binder tests developed under NCHRP Project 09-10, titled "Superpave Protocols for Modified Asphalt Binders," are also being evaluated. NCHRP Project 09-10 was completed in February 2001. For the materials tested in this study, good correlations between asphalt binder properties and laboratory mixture rutting resistance were found, which indicate that the current Superpave asphalt binder specification and testing protocols are valid. Additional mixtures will be tested by FHWA to verify these findings. This report will be of interest to highway personnel who use polymer-modified asphalt binders and Superpave.
T. Paul Teng, P.E.
Director, Office of Infrastructure
Research and Development
Notice
This document is disseminated under the sponsorship of the
U.S. Department of Transportation in the interest of information exchange. The
U.S. Government assumes no liability for the use of the information contained in this document.
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Technical Report Documentation Page
| 1. Report No.
FHWA-RD-02-042 |
2. Government Accession No. | 3 Recipient's Catalog No. | ||
| 4. Title and Subtitle
UNDERSTANDING THE PERFORMANCE OF MODIFIED ASPHALT BINDERS IN MIXTURES: PERMANENT DEFORMATION USING A MIXTURE WITH DIABASE AGGREGATE |
5. Report Date
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| 6. Performing Organization Code | ||||
| 7. Author(s)
Kevin D. Stuart and Walaa S. Mogawer |
8. Performing Organization Report No.
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9. Performing Organization Name and Address Office of Infrastructure Research and Development |
10. Work Unit No. (TRAIS) |
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| 11. Contract or Grant No.
In-House Report |
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| 12. Sponsoring Agency Name and Address
Office of Infrastructure Research and Development |
13. Type of Report and Period Covered
Final Report |
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14. Sponsoring Agency Code
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| 15. Supplementary Notes
FHWA Contact: Kevin D. Stuart, HRDI-11 |
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| 16. Abstract
The objective of this study was to determine if the Superpave high-temperature properties of polymer-modified asphalt binders correlate to asphalt mixture rutting resistance. An emphasis was placed on evaluating the rutting resistances of mixtures containing polymer-modified asphalt binders with identical (or close) performance grades, but varied polymer chemistries. This would indicate what types of modification provide properties that are, or are not, correctly captured by the current Superpave asphalt binder specification. Eleven asphalt binders were obtained for this study: two unmodified asphalt binders, an air-blown asphalt binder, and eight polymer-modified asphalt binders. Five binders used in a prior study were also tested. Asphalt binder properties were measured by a dynamic shear rheometer. Mixture rutting resistance was measured by: (1) G* and G*/sin(delta) from the Superpave Shear Tester (SST) frequency sweep at constant height, (2) cumulative permanent shear strain from the SST repeated shear at constant height (RSCH), (3) French Pavement Rutting Tester (French PRT), and (4) the Hamburg Wheel-Tracking Device. Cumulative permanent shear strain and the French PRT were the primary tests because they were specifically developed to measure rutting resistance. The high-temperature properties of the 11 asphalt binders had a high correlation to mixture rutting resistance as measured by the cumulative permanent shear strains. A weak correlation was found using the French PRT. Both correlations were high when analyzing the data from all 16 asphalt binders. A change in high-temperature PG from 70 to 76 significantly increased rutting resistance based on both tests. The main objective of this study was to determine which asphalt binders provide high-temperature properties that do not agree with mixture rutting resistance. In general, the number of discrepancies was low. It is recommended that the asphalt binders be tested using other aggregate types or gradations. |
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| 17. Key Words
Superpave, asphalt binder specification, permanent deformation, Superpave Shear Tester, SST, French Pavement Rutting Tester, Hamburg Wheel-Tracking Device, polymer-modified asphalt binders. |
18. Distribution Statement
No restrictions. This document is available to the public through the National Technical Information Service, Springfield, Virginia 22161. |
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19. Security Classification Unclassified |
20. Security Classification Unclassified |
21. No. of Pages 57 |
22. Price | |
| Form DOT F 1700.7 | Reproduction of completed page authorized |
Section
5. Evaluation Using G* and G*/sind
6. Cumulative Permanent Shear Strain
9. Evaluation of Data Without Statistical Analysis
10. Comparison of Mixture Tests
a. Conclusions Provided by the 11 Mixtures
b. Conclusions Provided by All Mixtures
LIST OF FIGURES
Figure No.
1. G* using new aggregate blend vs. G* using original aggregate blend
5. G*/sind of the asphalt mixture vs. G*/sind of the asphalt binder using the 11 asphalt binders
6. G*/sind of the asphalt mixture vs. G*/sind of the asphalt binder using all 16 asphalt binders
7. G*/sind of the asphalt mixture at 50°C vs. high-temperature PG using the 11 asphalt binders
8. G*/sind of the asphalt mixture at 50°C vs. high-temperature PG using all 16 asphalt binders
13. Cumulative permanent shear strain at 50°C vs. high-temperature PG using the 11 asphalt binders
17. French Pavement Rutting Tester
19. French PRT rut depth vs. G*/sind of the asphalt binder at 0.9 rad/s using the 11 asphalt binders
21. French PRT rut depth vs. G*/sind of the asphalt binder at 0.9 rad/s using all asphalt binders
23. French PRT rut depth at 70°C vs. high-temperature PG using the 11 asphalt binders
24. French PRT rut depth at 70°C vs. high-temperature PG using all asphalt binders
25. Hamburg Wheel-Tracking Device without water
26. Rut depth vs. wheel passes from the Hamburg WTD at 58°C
29. Log RSCH cumulative permanent shear strain vs. log FSCH G*/sind for all mixtures
LIST OF TABLES
Table No.
1. Comparison of SST properties provided by the original and new aggregate blends
2. Descriptions of the asphalt binders
3. Performance grade (PG) for each asphalt binder
4. Aggregate properties for the diabase
5. Volumetric properties of the mixtures
8. Replicate data for G*/sind at 50oC
9. G*/sind's of the asphalt binders vs. cumulative permanent shear strain
10. Statistical rankings for the 11 asphalt mixtures based on cumulative permanent shear strain
11. Replicate data for the cumulative permanent shear strains
14. Replicate data for the French PRT
16. Replicate data for the Hamburg WTD
17. Rankings by test type with the material having the most resistance to rutting listed at the top
19. Coefficients of determination, r2, using the data from the 11 mixtures
20. Coefficients of determination, r2, using the data from all mixtures
PERSONNEL
John S. Youtcheff and Kevin D. Stuart, FHWA, Turner-Fairbank Highway Research Center, 6300 Georgetown Pike, McLean, VA 22101-2296
Walaa S. Mogawer, Civil and Environmental Engineering Department, University of Massachusetts Dartmouth, North Dartmouth, MA 02747
Naga Shashidhar, Susan Needham, Scott Parobeck, and Frank Davis, SaLUT, Turner-Fairbank Highway Research Center, 6300 Georgetown Pike, McLean, VA 22101-2296
Aroon Shenoy, Senior Research Fellow, FHWA, Turner-Fairbank Highway Research Center, 6300 Georgetown Pike, McLean, VA 22101-2296
SI* (Modern Metric) Conversion Factors
