Anti-Ultraviolet Aging Properties of Nano-Sm2O3-Modified Asphalt Based on Experimental and Molecular Dynamics Simulations

The performance and service life of asphalt pavements are seriously reduced by asphalt ultraviolet aging. The commonly used anti-UV aging method is that anti-UV aging agent is added to asphalt. The effect of nano-Sm2O3 on the anti-UV aging performance of asphalt was discussed in this study in order to enrich the types of antiaging agents. Nano-Sm2O3 modified asphalt was prepared and segregation test was used to assess the compatibility of the modified asphalt. Then, the high-temperature performance and low-temperature performance of matrix asphalt and modified asphalt were evaluated using the dynamic shear rheometer (DSR) and the bending beam rheometer (BBR). And their functional group characteristics and microscopic behaviors were investigated by fourier transform infrared spectroscopy (FTIR), asphalt four components analysis and molecular dynamics simulation (MD). The results suggested that the storage stability of modified asphalt was met by all samples, in accordance with the specification requirements. The rutting factor of asphalt was improved by the incorporation of nano-Sm2O3, which resulted in better rutting resistance and reduced permanent deformation at high temperature. The optimum value was achieved with 2% of nano-Sm2O3. No new absorption peaks were observed to have been present on the infrared spectra of the asphalt modified with nano-Sm2O3, when compared to the matrix asphalt. This indicated that the addition of nano-Sm2O3 to asphalt was a physical modification. At the molecular level, the mechanical properties of asphalt are improved, the compatibility between asphalt and modifiers is enhanced, and the average movement rate of asphalt molecules is increased by the addition of nano-Sm2O3, thereby enhancing the rheological properties of asphalt. In conclusion, it is feasible for nano-Sm2O3 to be added into asphalt to resist UV aging.