Preparation of UV Aging‐Resistant SBS Polymer‐Modified Asphalt and Its Underlying Aging Resistance Mechanism

ABSTRACT To enhance the UV aging resistance of SBS‐modified asphalt and elucidate the underlying UV aging resistance mechanisms, this study developed a novel UV aging‐resistant SBS‐modified asphalt by incorporating UV absorbers and a light stabilizer. The dual mechanisms of UV aging in SBS‐modified asphalt were investigated from both macroscopic properties and microscopic structures through dynamic shear rheometer (DSR) test, bending beam rheometer (BBR) test, and Fourier transform infrared (FTIR) spectroscopy test. Furthermore, the synergistic effect of the UV absorbers and light stabilizer was examined via atomic force microscopy (AFM) and ultraviolet–visible (UV–Vis) spectroscopy. The test results demonstrate that the UV absorbers and light stabilizer significantly improve the UV aging resistance of SBS‐modified asphalt. The SBS‐modified asphalt has dual UV aging mechanisms, which involves both the oxidative aging of the base asphalt and the degradation of SBS polymer chains. The UV absorbers act by absorbing UV energy and converting it into thermal energy, thereby reducing the generation of free radicals in the asphalt matrix and suppressing the oxidation of asphaltene molecules. The light stabilizer further terminates the aging chain reaction by scavenging free radicals and decomposing hydroperoxides, thus inhibiting the aging and performance degradation of SBS‐modified asphalt.