Molecular Dynamics Study on the Effect of Mineral Composition on the Interface Interaction between Rubberized Asphalt and Aggregate

In order to explore the effect of aggregate type on the interface interaction between rubberized asphalt and aggregate, the representative molecules of base asphalt, rubberized asphalt, limestone (calcite), basalt (augite), and granite (quartz) were modeled by a molecular dynamics method. Additionally, asphalt–aggregate interface models were constructed by using the existing molecular models. The interface interaction between rubberized asphalt and different aggregates was analyzed by the radial distribution function (RDF), diffusion coefficient and adhesion energy density, and the simulation results were verified by a surface energy test. The results show that the interaction between asphalt and aggregate exists in the form of hydrogen bond, and the polarity of asphalt and aggregate has a great influence on the interaction. Calcite has the strongest interaction with asphalt among the three crystalline molecules. This conclusion further explains the phenomenon that alkaline aggregate has better adhesion to asphalt. The interaction between augite and crumb rubber is relatively strong, which leads to the maximum enhancement of the interaction between rubberized asphalt and augite. This study provides a reference for further research on the formation and failure of asphalt–aggregate interface interactions under various conditions and environments.