Abstract: To examine the time-evolving performance of acidic aggregate asphalt concrete in high-altitude and strong ultraviolet (UV) environments, this study selects acidic granite and alkaline limestone asphalt concretes for UV aging tests, and evaluates their mechanical properties by conducting beam bending tests. We develop a coupling model of temperature and UV radiation effects, using the response surface methodology (RSM) and three indicators－stress, strain, and critical flexural strain energy density. The results show UV aging causes chemical damage to the asphalt matrix, leading to the development and time-dependent propagation of cracks in the mixture, which results in a decrease in deformability. The damage effects vary significantly across different temperatures, and the material at 0 ℃ features a higher strength, a greater deformability, and the best UV resistance stability. As aging develops, the maximum difference in peak strain between limestone and granite asphalt concretes can reach 50%. This study reveals the performance degradation of acidic aggregate asphalt concrete in alpine and strong UV environments, and quantifies its differences from alkaline materials, laying a basis for selecting anti-seepage materials for asphalt concrete face slabs.

Key words: asphalt concrete; ultraviolet aging, granite aggregate, performance degradation, response surface methodology