Molecular and rheological assessment of crude corn oil for restoring self-healing in recycled asphalt binders

Abstract

The utilization of vegetable-based oils as asphalt modifiers has gained significant attention; however, the specific mechanisms by which crude corn oil (CO) enhances self-healing properties—particularly through integrated multi-scale analysis—remain underexplored. This study investigates CO as a sustainable recycling agent intended to restore the self-healing capability of aged asphalt binders. Specifically, it examines the effect of CO on the self-healing performance of a recycled binder (CR) composed of 65% reclaimed asphalt binder (R) blended with a base PG 64–28 binder, using both experimental testing and molecular dynamics (MD) simulations. The research employed simplified viscoelastic continuum damage theory (S-VECD) and pseudo strain energy (PSE) functions to assess damage tolerance, crack generation, and self-healing properties. Damage characteristic curve (DCC) analysis showed that CO had a positive effect on binder rheology, increasing the damage tolerance of the recycled binder and bringing its S -value (a scalar parameter representing material damage evolution) closer to that of the base binder. PSE results further confirmed that CO reduced microcrack formation in the recycled binder. MD simulations were used to evaluate the physical, thermal, and rheological binder properties, and used viscosity recovery (restoration of viscosity following microcrack formation) as a proxy for self-healing performance. The results indicated that CO restored viscosity, effectively rejuvenating the atomistic structure of the recycled binder. However, discrepancies between experimental self-healing (H _exp %) and simulation-based results (H _{s im} %) suggest that density recovery alone may not fully capture self-healing behavior when using the General AMBER force field (GAFF). Overall, this study highlights the complementary value of experimental and simulation approaches for evaluating the effectiveness of CO in enhancing the self-healing properties of recycled binders, offering potential benefits for asphalt pavement durability.