Study on aging mechanism of SBS/SBR compound-modified asphalt based on molecular dynamics

Abstract Component ratio change is considered to be the main reason leading deterioration of asphalt properties, but there are few studies on aging mechanism from perspective modifier molecules. To reveal styrene–butadiene–styrene block copolymer (SBS)/styrene butadiene rubber (SBR) compound-modified asphalt, micro in process was studied by combining molecular dynamics (MD) and Fourier transform infrared spectroscopy (FTIR). First, MD used establish models SBS/SBR at different stages (non-aging, short-term aging, long-term aging) verify its rationality. Second, characteristics model, such as solubility parameters, diffusion coefficient, interface interaction energy, radial distribution function, were analyzed calculation. Finally, FTIR results proved rationality simulation explained asphalt. The show that cohesiveness density parameters increase, coefficient decreases, stability increases during process. And, carbonyl index, sulfoxide aromatic ring index increased degrees after aging. study explains molecules provides a theoretical basis for research anti-aging.