Diffusion of asphaltene, resin, aromatic and saturate components of asphalt on mineral aggregates surface: molecular dynamics simulation

In this research, the models of four asphalt components (asphaltene, resin, aromatics and saturate) and five minerals (SiO₂, Al₂O₃, CaO, MgO and Fe₂O₃) were constructed individually, and then the interface models were constructed by adding the asphalt components and minerals together. The interfacial behaviour at molecular scale was simulated by setting boundary conditions, optimising the structure and canonical ensemble. The mean square displacement and diffusion coefficient of particles were selected to study the diffusion of asphalt components on the surface of different minerals. The results show that increasing the temperature can accelerate the diffusion of asphalt components. The diffusion speed of asphalt components on the surface of Al₂O₃ is faster than other mineral crystals. The temperature sensitivity of diffusion coefficient of asphalt components on the surface of CaO is the maximum. The diffusion speed of asphalt components ranked roughly as their molecular weight: saturate > aromatics > resin > asphaltene.