RAP Binder Influences on the Rheological Characteristics of Foamed Warm-Mix Recycled Asphalt

Foamed warm-mix technology can decrease the construction temperatures of asphalt mixtures, and recycling reclaimed asphalt pavement (RAP) can reduce waste production and resource consumption. Therefore, combining foamed warm-mix asphalt with RAP is an energy saving and resource recycling technology for pavement construction. However, few studies have focused on the interaction of new asphalt and RAP binder to determine the optimum amount of RAP binder in foamed warm-mix recycled asphalt by the rheological characteristics. In this study, foamed warm-mix recycled asphalts with different amounts of RAP binder were prepared in the laboratory. The influences of the amount of RAP binder on the rheological characteristics of foamed warm-mix recycled asphalt were investigated. The high-temperature and low-temperature performance, temperature susceptibility, antifatigue performance, recovery ratio (R%), and nonrecoverable creep compliance (J(nr)) were evaluated by temperature sweep tests, low-temperature bending tests, and multiple stress creep recovery (MSCR) tests. The results show that foamed warm-mix recycled asphalt exhibited better high-temperature performance, temperature susceptibility, and creep properties but inferior low-temperature performance and fatigue resistance. Furthermore, the optimum amount of RAP binder in foamed warm-mix recycled asphalt is higher than that in hot-mix asphalt. (C) 2017 American Society of Civil Engineers.