Molecular dynamics simulation insights into rejuvenating aged asphalt with waste soybean oil and polymers

This study utilized molecular dynamics simulations to assess the rejuvenation of aged asphalt (AA) with waste soybean oil (WSO) and functionalized SBS polymers, focusing on: 1) constructing and validating models for virgin asphalt (VA), AA, and composite rejuvenated asphalt with WSO and polymers; 2) analyzing diffusion effects and binding abilities in these rejuvenated models; 3) evaluating interface binding and diffusion behaviors in composite rejuvenated models. The addition of functionalized SBS molecules and WSO improved the diffusion rates of various components within these models. Specifically, functionalized linear-SBS (LSBS) molecules demonstrated superior diffusion performance compared to star-SBS (SSBS) molecules. Incorporating WSO and polymers into the AA model increased the occupied volume of all rejuvenated models. The free volume fraction (FFV) in rejuvenated asphalt models exceeded that in AA at 433 K, suggesting that the inclusion of WSO and polymers enhances molecular mobility. As temperature increased, the interaction energy between polymers and asphalt components decreased. LSBS molecules exhibited stronger interactions with asphalt components than SSBS molecules, whose interaction energy was significantly enhanced by hydrogenation treatment. In rejuvenated-rejuvenated asphalt models, the interface interaction energy was higher than in VA-VA models, suggesting improved interface stability. However, diffusion rates of various components in rejuvenatedrejuvenated asphalt models were lower than those in VA-VA models.