Impact of Waste Cooking Oil under Different Stages on Aged Asphalt-Mineral Interface Adhesion via Molecular Dynamics Simulations

Waste cooking oil (WCO) was investigated as an asphalt rejuvenator and found to have good potential. The properties of the WCO itself will change with usage and the WCO under different stages may affect the bond between the asphalt and minerals. In this study, the effect of WCO under different stages on adhesion behaviors of aged asphalt-mineral interfaces was explored through molecular dynamics (MD) simulations. The results show that triglycerides and treated fatty acids with low acid value can better improve the adhesion work between aged asphalt and acidic mineral (e.g., quartz), while fatty acids with high acid value may increase the adhesion work of aged asphalt to alkaline minerals (e.g., calcite and albite). Treated free acids are less effective in improving the moisture resistance of interfaces than free acids. Considering the coupling effect, WCO under different stages mostly can have restorative effects on the adhesion sensitivity of interfaces. The results can provide a reference for the selection of aggregates for WCO application in asphalt mixtures.