Laboratory performance characteristics of high modulus asphalt mixture with high-content RAP

Abstract

This study investigated the feasibility of using high-content reclaimed asphalt pavement (RAP) in high modulus asphalt concrete (HMAC). The design method of HMAC was adopted from the French Standard in which dynamic modulus were used to determine the optimum binder content and aggregate gradation. Laboratory performance tests, including high-temperature wheel tracking test, low temperature bending beam test, moisture stability test, and fatigue test, were conducted to evaluate mechanical performance of HMAC with different RAP contents. The effects of RAP content on performance of recycled high modulus asphalt concrete (RHMAC) depend on the specific RAP content and the performance indicator. In general, the RAP content shows significant influence on dynamic modulus and failure strain when the RAP content increases to 40%, while the RAP content shows significant impact on dynamic stability and tensile strength ratio when the RAP content increases to 50%. The RHMAC can be used in asphalt binder layer and base layer to provide good rutting resistance in long-lasting pavement (perpetual pavement) due to its high modulus and stability at high temperatures. However, considering the influences of RAP on low temperature performance and moisture stability, RHMAC is not suggested to be used in the surface layer with high RAP contents.