Study on the mechanism of bond strength generation and debonding failure between basalt fiber and asphalt based on molecular dynamics

Asphalt-basalt fiber interface models were established based on molecular dynamics to explore the microscopic bond characteristics between basalt fiber and asphalt. The debonding failure behavior between basalt fiber and asphalt was examined by comparing its bond strength and the asphalt diffusion coefficient. The effects of temperature and basalt fiber oxide on these variables were also examined. The findings demonstrate that the order of diffusion coefficients of the asphalt components on the surface of basalt fiber is as follows: saturate > aromatic > resin > asphaltene, where the diffusion activation energy of the saturate is the largest and more sensitive to temperature, while the diffusion of resin and asphaltene is less influenced by temperature. The interfacial energy between the four oxides of basalt fiber and asphalt is CaO > MgO > Al2O3 > SiO2 in descending order. As the temperature increases, the interaction force between internal molecules of asphalt becomes smaller, and repulsive forces appear between the asphalt interfaces when the temperature of asphalt is heated to 438 K. In the microscopic particle state, the basalt fiber reinforced asphalt is more prone to debonding failure within the asphalt, while the adhesion property of the basalt fiber and asphalt interface is relatively stable. The study's findings can serve as an experimental foundation for the inclusion of basalt fibers in asphalt mixtures.