Performance Studies and Future Directions for Mixes Containing RAP/RAS: Technical Report

In the last several years reclaimed asphalt pavement (RAP) and recycled asphalt shingles (RAS) have been widely used in asphalt mixes in Texas. The use of RAP/RAS can significantly reduce the initial cost of asphalt mixtures, conserve energy, and protect the environment. There are always two main concerns: variability of RAP/RAS and durability (or cracking) of RAP/RAS mixes. Past studies in Texas have clearly indicated that both RAP and RAS have acceptable variability following the best practices for handling RAP/RAS. This study focused on the durability problems of RAP/RAS asphalt mixes. First, extensive laboratory tests were performed to investigate the impacts of RAP/RAS on the durability of RAP/RAS blended binders and asphalt mixes. Second, a field survey on test sections with RAP/RAS mixes was conducted to identify how significant RAP/RAS are and which approach to improve the durability problems of mixes. Third, a pavement life cycling cost analysis on RAP/RAS mixes was conducted to investigate the financial benefits of them. Finally, the findings, conclusions, and recommendations for RAP/RAS mixes are made.