Comprehensive analysis of effect of high-acid-value waste cooking oil on adhesion between aged asphalt and aggregates

Waste cooking oil (WCO) has widespread applications in the rejuvenation of aged asphalt. A few investigations have been conducted on the multiscale adhesion properties and rejuvenation mechanism of aged asphalt-aggregate surfaces treated with high-acid-value WCO. This research focuses on the implications of WCO on the interfacial adhesion of aged asphalt from both macroscopic and microscopic structural viewpoints. The asphalt–aggregate interfacial adhesion was macroscopically assessed through binder bond strength (BBS) tests, and the microscopic mechanism of activation was investigated using a molecular dynamics model. The findings show that through promoting microstructure recovery and mitigating the adverse consequences of aging, WCO might enhance the adhesion strength of aged asphalt. Although the effects of aging on asphalt interface adhesive depend on mineral category, WCO could enhance adhesion along with moisture resistance over the aged asphalt-aggregate boundary. Furthermore, binding strength and interface adhesion work have a strong positive association. This research provides an exhaustive knowledge of the adhesive characteristics of the asphalt-aggregate interface at the multiscale level.