Molecular simulation of graft-activated crumb rubber modified asphalt: A study on high temperature performance and its interface behavior with aggregate

Abstract

The action mechanisms of crumb rubber (CR) and graft-activated crumb rubber (GACR) on the high temperature properties of modified asphalt and their adhesion to aggregate were investigated through molecular dynamics simulation. From the molecular level analysis, grafting activation changed the arrangement and distribution of modified asphalt molecules, enhanced the binding capacity, and limited the free movement and diffusion of molecules. The strong ductility and polarity of GACR could promote the entanglement of polar molecules and increase the viscosity of the system. In the process of interaction with aggregate, compared with crumb rubber modified asphalt (CRMA), it was found that GACR modified asphalt (GACRMA) diffused rapidly to the surface of aggregate, the proportion of polar components at the proximal end of aggregate was high, and the effect of spreading and adhesion was better. This was the result of the interaction between GACR and polar molecules in asphalt and the multiple effects of van der Waals forces and hydrogen bonds derived from aggregate. The macroscopic experiments confirmed the accuracy of the simulation, indicating that molecular simulation can effectively reveal the modification mechanism and predict the properties of modified asphalt.