Effect of RAP, RAS, and Aging on tlie Workability of Asphalt Mixes

摘要

A simple and easy-to-use test method, called the 'Dongre Workability Test' (DWT - pronounced DWIGHT), uses the Superpave Gyratory Compactor (SGC) to determine asphalt mix workability. The test is able to resolve differences in workability due to aggregate gradation, asphalt binder grade, Warm Mix Asphalt (WMA) additives and polymer modification. A predictive chart was also developed to estimate field compaction temperatures using the DWT test values. The DWT was used to determine the effect of Reclaimed Asphalt Pavement (RAP), Recycled Asphalt Shingles (RAS), and aging of loose mix on workability. Eleven mixes from the recently constructed test lanes at the Federal Highway Administration (FHWA) Accelerated Loading Facility (ALF) were tested. Two base binders (PG 64-22 and PG 58-28) were used with various RAP and RAS contents. Two types of WMA additives were also included in the experiment. Three aging conditions were imposed on all mixes from the FHWA ALF 2014 construction. Results suggest that DWT is able to quickly and successfully characterize the effect of RAP, RAS and aging severity on the workability of asphalt mixes. The implementation potential of the DWT in a possible field Quality Assurance (QA) scheme is also examined in the paper.