Evolution of asphalt performance under the coupled aging of ultraviolet, high temperature and water

During the service of asphalt pavement, it is affected by natural environmental factors for a long time, and the pavement performance declined. In order to simulate the cumulative effects of multiple aging components, the indoor "ultraviolet radiation, high temperature and water" multi-factor cyclic coupling aging test was designed. The properties of asphalt during cyclic coupled aging were measured by conventional physical properties tests, photoelectric colorimetric tests, and Fourier Transform Infrared Spectroscopy test. Then the surface morphology of asphalt was observed by camera and optical microscope. After asphalt aged, a large number of oxidation functional groups were formed, causing asphalt to become hard and brittle, adhesion to diminish, and surface roughness to increase. Ultraviolet light and high temperatures led to the exudation and dissolution of the liquid constituents within the asphalt, which were subsequently washed away by water. The thermal stress induced the shrinkage and wrinkle of the asphalt film, resulting in the formation of cracks. Under high temperatures, a limited number of cracks could potentially self-repair during the early stages of aging. Nevertheless, as the aging process progressed, the self-healing capacity of the asphalt diminished, leading to the widening and deepening of cracks. Concurrently, water infiltrated along the cracks into the inner layers of the asphalt, exacerbating the degradation of its properties.