Investigating the impact of calcium sulfate whisker on the microscopic properties of basalt fiber-reinforced asphalt using molecular dynamics simulation

The purpose of this study is to investigate the impact of calcium sulfate whiskers (CSW) on the microscopic properties of basalt fiber-reinforced asphalt using the molecular dynamics (MD) simulation. In this study, the asphalt molecular model, fiber-reinforced asphalt molecular model, and asphalt-fiber interface model were established using Materials Studio 8.0 software. Then, the impact of CSW on the microscopic physical properties of basalt fiber-reinforced asphalt and the impact of CSW on the interface interactions in composite fiber-reinforced asphalt were investigated. The results show that the microphysical moduli of basalt fiber-reinforced asphalt can be improved by the addition of CSW. The inclusion of CSW can alleviate the molecular aggregation of asphaltene and resin and enhance the orderliness of asphalt molecules. Moreover, introducing CSW into basalt fiber-reinforced asphalt can elevate the interfacial energy between asphalt and fibers. It also increases the relative concentration distribution of asphalt molecules on the surface of basalt fibers. These indicate that more asphalt has been adsorbed on the surface of the basalt fibers, thereby strengthening the interfacial adhesion between asphalt and fibers. Furthermore, the type of silane coupling agent and the content of CSW are recommended through MD simulation. Finally, the dynamic shear rheolometer test and the multiple stress creep recovery test were used to investigate the rheological and interfacial properties of fiber-reinforced asphalt, and conclusions of laboratory tests correlated well with the results of MD simulation.