Influence of graphene on the composite modified asphalt based on viscoelastic and elastic properties

In order to explore high-viscosity, high-elasticity composite modified asphalt materials suitable for drainage pavements, different dosages of graphene-modified asphalt and graphene composite-modified asphalt were prepared. Elastic recovery efficiency and rotational viscosity as the main experimental indicators for modified asphalt are employed to determine the optimal dosage of graphene and help conduct a study on the viscoelastic properties, analyzing the fatigue performance of the modified asphalt through linear amplitude sweep (LAS). Based on molecular dynamics simulation (MD) to build an asphalt model, the study on viscoelastic properties uses calculated viscosity and the asphalt glass transition temperature range (Tg) obtained from simulation results as indicators to verify the optimal dosage of graphene. Scanning Electron Microscopy (SEM) is utilized to reveal the effects of different dosages of graphene modification. The research results indicate that the optimal dosages of graphene in graphene-modified asphalt and graphene composite-modified asphalt are 0.1 % and 0.2%, respectively. At these concentrations, graphene significantly enhanced the elastic recovery properties of the matrix asphalt (113% increase) and the composite-modified asphalt (28% increase). In terms of rotational viscosity, the matrix asphalt saw a 54% rise with the addition of graphene, while the composite-modified asphalt experienced a substantial 151 % increase. Notably, the incorporation of graphene also resulted in a rise in the glass transition temperature and a reduction in the length of the graphene-modified asphalt, signifying an improvement in its elastic properties. Furthermore, the calculated viscosity of the graphene-modified asphalt and composite-modified asphalt surged by 47.49 % and 64.01 %, respectively. Additionally, SEM results indicate that differences in the effects of graphene modification are primarily due to the dispersion and coating extent of graphene.