Molecular Dynamics Study of the Effects of Microwave Heating on the Physical and Mechanical Properties and Interface Interactions of Asphalt

Abstract

The development and application of microwave heating technology in asphalt pavement is a hot research topic in the road field. This study aims to delve into the micro-scale properties of asphalt after microwave heating. Based on four-component experiments and infrared spectroscopy experiments, asphalt molecule models, as well as aggregate and moisture models after oven heating and microwave heating, were established using Materials Studio simulation software. The density changes, radial distribution functions, and mechanical properties were calculated using the Forcite module. Additionally, the diffusion and adsorption of asphalt on the surfaces of aggregates and moisture were computed to characterize its bonding characteristics. The research findings indicate that microwave heating leads to changes in the asphalt components, resulting in a corresponding decrease in the molecular density of the asphalt. Due to these component changes, the mechanical properties of the asphalt are somewhat diminished after microwave heating. Microwave heating also results in a uniform dispersion of asphalt components, as evidenced by the radial distribution function, which shows that microwave-heated asphalt is more uniformly dispersed with a reduced packing density. In terms of diffusion and adsorption, the results show that the diffusion coefficients of asphalt on the surfaces of aggregates and moisture decrease after microwave heating, along with a reduction in the interaction energy with aggregates and moisture. This suggests a relative decrease in the activity of asphalt molecules after microwave heating. Similarly, the calculations of interaction energy indicate improved resistance to water aging for asphalt after microwave heating. These research findings provide valuable theoretical guidance for the application of microwave heating in the field of road engineering.