Concerns with the performance of hot mix asphalt (HMA) that contains recycled materials have recently become the focal point of the asphalt industry. Recycled materials used in HMA in Washington may include reclaimed asphalt pavement (RAP), reclaimed asphalt shingles (RAS), and recycled engine oil bottoms (REOB). In the late 2000’s recycled materials use increased as the economy crashed, market competition increased and margins decreased, and virgin asphalt binder cost increased significantly. However, the impacts of that increased usage are beginning to be better understood, and transportation agencies are determining that the durability of HMA may have been compromised as a result. The primary objective of this project is to increase the understanding of the effects of recycled materials on HMA performance and durability to enhance WSDOT’s HMA materials selection, mix design process, and standard specifications. The results are intended to help WSDOT modify its overall recycled materials strategy so that it is informed by current national best practices, takes into account observable local issues and test results, and leads to more durable HMA pavements.
Principal Investigator: Steve Muench, Civil and Environmental Engineering, UW
Sponsor: WSDOT
WSDOT Technical Monitor: Joe DeVol
WSDOT Project Manager: Jon Peterson
Scheduled Completion: March 2021