Rejuvenation effect evaluation and mechanism analysis of rejuvenators on aged asphalt using molecular simulation

In this study, the effects of aromatic and long-chain rejuvenators on aged asphalt were investigated by molecular simulations. Asphalt integration and free diffusion models were constructed for simulating asphalt properties and aggregation behavior. The viscosity, cohesive energy density (CED), and glassy transition temperature (Tg) were calculated from the dynamics simulations. The structural and energetic changes in asphalt colloids were investigated by radial distribution function (RDF) of aromatic components and interaction energy of asphalt colloid. The results of integrated model simulations of asphalt properties show that both rejuvenators restored viscosity, CED, and Tg of asphalt. The long-chain rejuvenator as a complement to the asphalt oil fraction is significant in improving the properties of aged asphalt. The RDF results indicate that the aromatic rejuvenator has a dispersing effect on the aggregation of asphalt aromatic components. The interaction energy results reveal that the rejuvenator contributes to a new microstructure instead of restoring the aggregate.