Experimental and Molecular Dynamics Simulations Investigating the Flexibility and Compatibility of Epoxidized Soybean Oil–Reinforced Epoxy Asphalt

Abstract

Epoxy asphalt has attracted widespread attention for its excellent high-temperature stability and fatigue resistance. However, the poor flexibility and compatibility of epoxy asphalt limit its application. This study used epoxidized soybean oil (ESO) as a toughener and compatibilizer to modify epoxy asphalt, and the influence of ESO on the mechanical properties and compatibility of epoxy asphalt was analyzed. The results indicate that ESO’s unique aliphatic long-chain structure effectively enhances the flexibility of epoxy asphalt and improves its compatibility. The mechanical properties of epoxy asphalt are optimal when ESO content reaches 10%, and the tensile strength of 10%-ESO-EA was 2.65 MPa and the elongation at break was 183%, which was a 50% increase in elongation at break. In addition, ESO reduces the viscosity growth rate of epoxy asphalt, which is beneficial to construction. Molecular dynamics simulations revealed that the inclusion of ESO weakens intermolecular interactions, reducing the cohesive energy density of epoxy asphalt. With increasing ESO content, the proportion of flexible chain segments in epoxy asphalt rises, enhancing molecular chain mobility, decreasing intermolecular binding forces, and reducing the glass transition temperature (Tg) of epoxy asphalt.