Evaluation of the Use of Reclaimed Asphalt Pavement in Stone Matrix Asphalt Mixtures

Abstract

Mixtures that contain reclaimed asphalt pavement (RAP) can typically perform as well or better than conventional HMA mixes. However, use of RAP has generally not been extended to stone matrix asphalt (SMA) production. This study evaluated the effect of RAP on combined aggregate properties, asphalt binder properties, and overall performance of SMA mixtures. The effect of type and size of RAP, as well as aggregate source on overall mix performance was also evaluated. Four types of RAP were combined at four levels (0%, 10%, 20% and 30%) with four aggregate sources. One source of virgin asphalt cement (PG76-22) was used in this study. Testing was performed to evaluate LA abrasion and flat and elongated particle content of the virgin and recycled aggregate blends. The effect of RAP addition on the rheological properties and performance grades of the combined binder blends was also evaluated. Finally, testing was performed to determine potential binder effect on resistance to moisture susceptibility, resistance to rutting, thermal cracking potential and fatigue life of the recycled mixtures. Results showed that only fatigue life of the mixes decreased significantly with the addition of RAP, but damage can be minimized by limiting the use of recycled SMA mixes to the top layers of the pavement and ensuring a good bond with the underlying layer. Overall, up to 20% RAP could be used without significantly affecting the performance of the mixes.