Abstract: In order to improve the adhesion between matrix asphalt and aggregate, four representative polymers, polyethylene(PE), SBS, SBR and polyurethane(PU), were selected to modify them, and molecular dynamics(MD) simulation method was used to simulate the models of asphalt-aggregate and asphalt-water-aggregate in different working conditions, and the simulation results were verified by laboratory tests. By analyzing the relative concentration distribution curve, the variation law of the polar components of asphalt was obtained. On this basis, the adhesion of each modified asphalt mixture at different temperatures was studied, and its mechanism was analyzed according to the relative concentration parameters. Finally, the applicable conditions were obtained by comparing the modified properties of the polymers. The results show that PE has good compatibility with asphalt, but the water stability of PE modified asphalt mixture is poor. SBS modified asphalt can maintain high adhesion in environments with large temperature difference. SBR modified asphalt has outstanding adhesion under low temperature conditions and superior water stability, which is suitable for low temperature and rainy areas. PU modified asphalt has good comprehensive performance and strong applicability in environments with complex climatic conditions such as high temperature and rain.
Keywords: modified asphalt; molecular dynamics(MD); adhesion; water stability index; relative concentration