Deterioration of low-temperature property of modified asphalt under ultraviolet ageing considering physical hardening

The low temperature and ultraviolet (UV) radiation in the cold, high-altitude area could induce physical hardening or UV ageing of asphalt. This study evaluated the property variation of modified asphalt under UV ageing and physical hardening. The microstructural property of asphalt was revealed based on Fourier transform infrared spectroscopy and atomic force microscopy tests. Subsequently, the deterioration of asphalt low-temperature property was investigated using bending beam rheometer and single-edge notched beam tests, and the sensitivity of asphalt low-temperature property indexes to UV ageing and physical hardening was analysed. Here we showed that the UV ageing deteriorated the chemical functional groups and microstructure of asphalt. The coupled effect of physical hardening and UV ageing severely worsened asphalt low-temperature property compared to the single physical hardening effect. It was proposed to adopt creep stiffness and crack tolerance as the asphalt low-temperature property evaluation index under UV aging and physical hardening.