Low-temperature Performance and its Microstructure of SBS Modified Asphalt under Condition of Aging

Abstract

The effects of USP warm-mixed agent, Evo warm-mixed agent and aging degree on the low temperature performance and micro-morphology of SBS modified asphalt were analyzed by ductility test, bending creep stiffness test (BBR) and atomic force microscope (AFM) scan test. The test results show that: The ductility test analysis shows that USP warming agent can improve the low temperature performance of SBS modified asphalt in the positive temperature zone, and aging reduces the ductility of warm mixed asphalt, in which Evo warm mix asphalt has the strongest ability to resist thermal aging. BBR test analysis shows that USP warm mixed agent improves the low temperature performance of the negative temperature zone of SBS modified asphalt, but this improvement is limited by the aging effect, the comparison analysis found that creep loading time had a significant impact on the creep compliance derivative, it is more than the effect of warm-mixed agent, and aging can accelerate warm mix asphalt into the creep stability period; AFM micro-scanning found that the "bee-like structure" appeared on the front topography of SBS modified asphalt and Evo warm asphalt. The bee-like structure of Evo warm mix asphalt is larger and more numerous. The larger the size of the bee structure, the smaller the number of bee structures; however, the surface of the USP warm mix asphalt is more undulating; the aging of the two types of asphalt is more serious, and the size of the honeycomb structure is larger, but the number of honeycomb structure is reduced; while the surface of USP warm asphalt is undulating.