Deterioration Effects of Oxidative Aging on Graphene-Asphalt Nanocomposite Interfaces: Multiscale Modeling

The purpose of this study is to explore the mechanism of interfacial degradation of graphene-asphalt nanocomposites by oxidative aging and to explain the principle of reduced cracking resistance. In this study, density functional theory (DFT), molecular dynamics (MD) simulation, atomic force microscopy (AFM), Fourier transform infrared (FTIR) spectroscopy, and linear amplitude scanning test (LAS) were used to quantify the effect of oxidative aging on the interfacial degradation of graphene-asphalt nanocomposites with different scales, and the coupling mechanism between scales was systematically analyzed. The results show that interfacial degradation is a complex multiscale coupling behavior. Oxidative aging reduced the fatigue life (N) of graphene-asphalt nanocomposites by 8.6% due to a 63.9% reduction in shear barriers and a 14.2% reduction in energy barriers at the molecular interface. Furthermore, oxidative aging enhanced the intermolecular interactions and compatibility of the graphene-asphalt molecules. The interfacial interaction of aged graphene-asphalt nanocomposites is mainly van der Waals force. Graphene-aged aromatics and graphene-aged saturates were the most compatible interfaces, and there was typical benzene ring stacking between graphene and aged aromatic 2. Aged aromatics and aged saturates are the main promoters of interfacial strength and stress transfer, while aged asphaltenes and aged resins sometimes play a weakening role, as verified by the AFM. In addition, DFT calculations show that there is no chemical reaction between graphene and aged asphalt molecules, which is consistent with the FTIR results. This study provides a theoretical basis for the development of targeted antiaging and anticracking technologies for asphalt-based materials.