Effect and mechanism of aging evolution on the rheological and fatigue properties of SBS-modified asphalt

The performance of SBS-modified asphalt (SBSMA) deteriorates seriously due to aging. In this research, aging evolution experiments were conducted on base asphalt (BA) and its SBSMA. The rheological and fatigue properties of BA and SBSMA with different aging degrees were assessed through a series of Dynamic Shear Rheometer (DSR) tests. The changes in the chemical functional group and the morphology of BA and SBSMA were analysed through the Fourier Transform infra-red spectroscopy (FTIR) and the fluorescence microscope to elucidate aging evolution mechanisms. The results show that the aging process for BA and SBSMA can be divided into two stages, the first aging rate is fast and the second aging rate is slow. The SBS degradation in SBSMA occurs primarily in the first aging stage, which shortens the rapid changes of rutting resistance and creep performance for SBSMA and enhance its high-temperature stability. The fatigue life of SBSMA increases by almost one order of magnitude larger than the BA due to SBS under the same aging time. The fatigue life of BA and SBSMA increases rapidly first and then slowly during aging, moreover, the external forces also have a certain impact on the fatigue life.