Laboratory and field performance investigation of anti-ultraviolet aging of warm-mixed asphalt concretes

MgAl-Layered double hydroxides (LDHs) is commonly applied to improve the anti-ultraviolet (UV) aging performance of SBS-modified asphalt concretes. However, LDHs elevates the mixing temperature of SBS-modified asphalt, resulting in more energy consumption and more volatile organic compounds (VOCs) emission. The surface-active warm-mixed agent (W-MA) can effectively reduce the viscosity of asphalt binder. This study explored the use of W-MA in LDHs/SBS-modified asphalt binder (LA) and LDHs/SBS-modified asphalt mixtures (LAM) to reduce the mixing temperature and VOCs emission. Firstly, the structural stability of LDHs and the effect of W-MA on viscosity reduction and VOCs emission in LA were studied. Then, the physical properties, UV aging resistance, and optimal LDHs content of warm-mixed LAM were examined. Finally, the performances of the test road applying warm-mixed LAM were investigated. The results demonstrated that the excellent structural stability of LDHs and the application of W-MA could effectively reduce the viscosity of LA and VOCs emission. Warm-mixed LAM exhibited excellent UV aging resistance and high-temperature performance. However, its lowtemperature performance and moisture damage resistance performance were slightly lower than warm-mixed asphalt mixtures. The optimal LDHs content in warm-mixed LAM was found to be 3 wt%. The test road showed minor differences in road performance compared to that in the laboratory, and the test road has great anti-UV aging performance.