Molecular dynamics simulation of interfacial adhesion behavior between waterborne epoxy resin emulsified asphalt and aggregate

Understanding the microscopic adhesion behaviour and mechanism of waterborne epoxy resin emulsified asphalt (WEREA) at the aggregate interface is quite significant for improving the service life of pavements. This work created an interface model of WEREA and aggregate using molecular dynamics (MD) simulation to examine the interface adhesion behavior. The interface model based on MD simulation was used to evaluate the distribution characteristics of asphalt components on the aggregate surfaces by calculating the thermodynamic properties, radial distribution function (RDF), relative concentration (RC) distribution and mean square displacement (MSD). The results show that WEREA has better thermodynamic characteristics than base asphalt and has components with much better self-polymerization behaviour. WEREA adheres more tightly to alkaline aggregates than acidic ones. Van der Waals forces dominate interfacial adhesion to acidic aggregates, while that to alkaline aggregates is dominated by electrostatic forces. Interfacial water damage is a spontaneous reaction. Moisture has a substantial influence on asphalt – aggregate adhesion, especially with alkaline aggregates. This work provides an effective method for exploring WEREA – aggregate adhesion.