Effect of functionalization and defects on thermal conductivity of graphene sheets modified asphalt nanocomposites

Functionalized graphene has great potential to improve the energy harvesting properties of asphalt pavements due to its superior thermal conductivity. However, the effects of functional groups and defects of graphene on the thermal conductivity of asphalt/graphene nanocomposites remain unclear. In this study, the influence of functional groups and defects on the thermal conductivity of graphene modified asphalt are comprehensively explored by molecular dynamics simulations. Results show that functionalized graphene is beneficial to the interfacial thermal conductance, and the butyl group increases twofold due to its interfacial penetration compared to the pristine one. The incorporation of functionalized groups can promote phonon transport at the asphalt/graphene interface. The predominant factor determining the thermal conductivity of asphalt nanocomposites changes from the interface-dominant mode to the filler-dominant mode when crossing the critical size. These findings can provide valuable information on the role of functional groups and defects in the thermal conductivity of asphalt nanocomposites, which is beneficial for developing asphalt pavements with advanced energy harvesting ability.