Evaluation of Conventional Elastic Recovery Tests for Modified Binders

Le résumé fourni par la source

Polymers, rubbers, and acids have been widely used for asphalt binder modifications. Different state and highway agencies follow different performance grade (PG) plus test techniques to characterize polymer-modified binders. The elastic recovery (ER) test method (AAHSTO T 301) is one of the most commonly used PG Plus test techniques to determine the presence of elastomeric modifiers. However, the ER test method is not suitable to determine the mechanical properties of the polymer-modified binders beyond its linear viscoelastic range and there is no uniform guideline to conduct the ER test. Thus, the main research goal of this study is to recommend alternative test method(s), which can possibly be pursued by using a commonly available device, a dynamic shear rheometer (DSR). Guidelines have been developed toward adopting the appropriate test method(s) so that neither suppliers nor users are penalized. In this study, the Arkansas Department of Transportation (ARDOT) and the Texas Department of Transportation (TXDOT) certified SBS-modified PG 70-22 and PG 76-22 binders collected from ten sources were investigated in the laboratory. Test procedures including multiple stress creep and recovery (MSCR), ER-DSR, linear amplitude sweep (LAS), and binder yield energy test (BYET) have been explored to find their effectiveness. After exploring the DSR-based tests, it is concluded that the presence of the elastomer can be identified through ER-DSR and MSCR tests. The ER-DSR test has been found to be the best alternative to the ER test method. The MSCR percent recovery (%R) parameter was also found to have a good correlation with the ER.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.