road works;  UV photoaging;  performance;  microscopic analysis;  Aging mechanism

In order to study the behavior and mechanism of asphalt ultraviolet aging, two kinds of bitumen were used for indoor simulated photoaging test. Through the analysis of viscosity and ductility time ratio of bitumen at different aging times, the decay behavior of high and low temperature performance of asphalt UV aging was studied, and the microscopic changes and aging mechanism were discussed by component test, colloidal structure and infrared spectroscopy(IR) analysis. The results show that UV aging mainly occurs on the surface of asphalt, resulting in a significant attenuation of the low temperature performance of asphalt. The effect on high temperature performance is relatively small; The aromatic components and gums in bitumen are sensitive to ultraviolet light. It is easy to generate asphaltenes by photooxidation reaction, the colloidal instability index and relative carbonyl index are increasing, and the asphalt properties are constantly deteriorating.