Mechanism and performance of graphene modified asphalt: An experimental approach combined with molecular dynamic simulations

Abstract

Nanoscale materials have gradually been a hot spot in improving asphalt performance. Thus, graphene modified asphalt (GMA) was prepared and its modification mechanism and mechanical properties were analyzed in this study. Three kinds of graphene powders (A, B, and C) with different molecular sizes were selected for evaluation. Molecular dynamics (MD) simulation results showed that GMA-B exhibited optimized comprehensive mechanical performance. In further experiments for GMA with different B dosages, it was found that adding graphene to asphalt was just a physical mixture, not a chemical reaction. Graphene dosage should not exceed 4 % because the agglomeration phenomenon was more severe, and the distribution uniformity was poor. Besides, the rutting and aging resistance continuously improved, while the low-temperature crack resistance decreased with graphene dosage. When it was 4 %, the low-temperature performance of GMA did not meet the demand, and the UV aging resistance of GMA was lower than that of 70# base asphalt. In summary, 2–3 % graphene powder dosage is recommended, depending on the emphasis on high or low temperature performance.

Keywords

• Graphene powder modified asphalt
• Molecular dynamics
• Modification mechanism
• Macroscopic test
• Microscopic test