Effects of Oxygen Isolation and Light–Oxygen Coupling Ultraviolet Aging on Adhesion, Micromorphology, and Functional Groups of Warm-Mix Asphalt

Abstract

To investigate the water damage effects and aging mechanism of warm-mix asphalt (WMA) after oxygen isolation and light–oxygen coupling ultraviolet (UV) aging, contact angle and adhesion performance tests were performed. The UV aging mechanism of WMA was analyzed using Fourier transform infrared spectroscopy and atomic force microscopy. The relationship between adhesion and surface roughness of WMA after UV aging was established. The test results indicated that as aging time increased, the water damage resistance of WMA gradually weakened. After the UV aging time exceeded 150 h, the adhesion performance of WMA gradually stabilized, and the addition of oxygen increased the UV aging effect. Additionally, the formation of strong polar substances and oxygen-containing functional groups precipitated by asphaltene gelation is the main reason for the attenuation of WMA adhesion performance.