Laboratory evaluation of moisture susceptibility of foamed warm mix asphalt containing high percentages of RAP

A laboratory study was conducted to evaluate the moisture susceptibility of plant-produced foamed warm mix asphalt (WMA) containing high percentages of recycled asphalt pavement (RAP) in Tennessee. WMA loose mixtures were collected and compacted at asphalt plant and were compared to hot-mix asphalt (HMA) samples through laboratory performance tests. In addition to widely-used AASHTO T283 freeze and thaw (F–T) and tensile strength ratio (TSR) tests, Superpave indirect tension (IDT) tests, dynamic modulus test, and Asphalt Pavement Analyzer (APA) Hamburg wheel tracking test were also utilized to evaluate asphalt mixtures subjected to freeze–thaw (F–T) and moisture-induced stress tester (MIST) moisture conditioning. The results indicated that the Superpave IDT tests and the dynamic modulus test had potential to accurately characterize moisture susceptibility. With incorporation of RAP, foamed WMA is expected to perform as well as HMA in terms of moisture susceptibility.