Technical Report Documentation Page 1. Report No. FHWA/TX-05/1872-2 2. Government Accession No. 3. Recipient's Catalog No. 4. Title and Subtitle DEVELOPMENT OF A NEW METHOD FOR ASSESSING ASPHALT BINDER DURABILITY WITH FIELD VALIDATION 5. Report Date August 2005 6. Performing Organization Code 7. Author(s) Charles J. Glover, Richard R. Davison, Chris H. Domke, Yonghong Ruan, Pramitha Juristyarini, Daniel B. Knorr, Sung H. Jung 8. Performing Organization Report No. Report 0-1872-2 9. Performing Organization Name and Address Texas Transportation Institute The Texas A&M University System College Station, Texas 77843-3135 10. Work Unit No. (TRAIS) 11. Contract or Grant No. Project No. 0-1872 12. Sponsoring Agency Name and Address Texas Department of Transportation Research and Technology Implementation Office P.O. Box 5080 Austin, Texas 78763-5080 13. Type of Report and Period Covered Research: September 1998 - August 2002 14. Sponsoring Agency Code 15. Supplementary Notes Research performed in cooperation with the Texas Department of Transportation and the U.S. Department of Transportation, Federal Highway Administration. Research Project Title: Evaluate Non-Specification Properties for Performance Graded Asphalts Which May Affect Performance 16. Abstract This project was a comprehensive study directed at developing an improved method of screening asphalt binders for long-term pavement performance. A new dynamic shear rheometer (DSR) function and a new aging procedure should warn of premature asphalt hardening and resulting fatigue cracking. For unmodified asphalts the new DSR function GN/(0N/GN) correlated well with ductility (at 15 o C, 1 cm/min) below 10 cm. The correlation was originally developed for DSR measurements at 15 o C and 0.005 rad/s. These conditions were time-temperature superposition shifted to 44.7 o C and 10 rad/s to produce a method that is easily accessible to standard laboratory rheological equipment and methods. The recommended aging procedure uses the pressure aging vessel (PAV) apparatus but takes advantage of the higher average aging rate when the asphalt is aged in thinner films. This change, combined with somewhat longer aging, results in a more rigorous test of durability than the standard PAV method. At the same time, the resulting rankings of aged materials are more representative of rankings that are obtained from aging at atmospheric air pressure and 60 o C. For modified asphalts, the results were complex. Generally for a given value of the DSR function, the ductility was better than indicated by the unmodified asphalt DSR-ductility correlation. Larger amounts of modifier produced increasing values of ductility for a given function value. This result was very asphalt dependent, however, so no general correlation could be found. As modified binders oxidize, the asphalt hardens and the improvement to ductility imparted by modifiers decreases. After enough aging, the improvement is gone and modified binders perform no better than their aged unmodified counterpart. A critical issue is whether the life extension produced by modifiers is life-cycle cost effective. Long-Term Pavement Performance (LTPP) and SH 21 binders indicate: sealcoats may provide an opportunity for significant and very cost-effective in-place binder rejuvenation; GN/(0N/GN) is an excellent function for tracking pavement aging; pavements can oxidize rather uniformly with depth; brittle binders can be tolerated in stiff pavements; aggregates appear to have little effect on asphalt oxidation reactions; rolling thin-film oven test (RTFOT) plus PAV aging is not severe aging, in the context of pavement life. 17. Key Words Asphalt Oxidation, Ductility, Asphalt Durability, Asphalt Aging, Superpave, Maxwell Model, Failure Stress, Failure Strain, Aging Test 18. Distribution Statement No restrictions. This document is available to the public through NTIS: National Technical Information Service 5285 Port Royal Road Springfield, Virginia 22161 19. Security Classif.(of this report) Unclassified 20. Security Classif.(of this page) Unclassified 21. No. of Pages 334 22. Price Form DOT F 1700.7 (8-72) Reproduction of completed page authorized.
DEVELOPMENT OF A NEW METHOD FOR ASSESSING ASPHALT BINDER DURABILITY WITH FIELD VALIDATION
Apr 26, 2023
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