Investigation of the interfacial interaction of carbon nanomaterials with asphalt matrix: insights from molecular simulations

The interfacial interaction between carbon nanomaterial and the asphalt matrix plays a key role in the capacity for load transfer and the mechanical properties of asphalt-carbon nanocomposites. In this study, molecular dynamics (MD) simulation was used to explore the interfacial interaction between carbon nanomaterials and asphalt molecules. The microscopic interface characteristics were evaluated by scanning electron microscopy and atomic force microscopy. The high temperature properties of asphalt-carbon nanocomposites were studied by a dynamic shear rheometer. The results showed that carbon nanotubes (CNT) had the best compatibility with aromatics (minimum binding energy of 11.05kcal/mol), the second compatibility with saturate (minimum binding energy of 10.05 kcal/mol), and the lowest compatibility with asphaltene (maximum binding energy of 4.19 kcal/mol). The compatibility of graphene with the four components also follows the above rule, but graphene-asphaltene compatibility is better than CNT-asphaltene because the maximum binding energy of graphene-asphaltene is 4.63kcal/mol. CNT competes with asphaltene for nonpolar components, whereas graphene is encapsulated by asphaltene, which results in different interactions between CNT-asphalt and graphene-asphalt nanocomposites. However, neither CNT nor graphene changed the colloidal structure of asphalt.