Molecular dynamics simulation of mechanical properties of intercalated GO/C-S-H nanocomposites

Graphene oxide (GO) cementitious composites have recently attracted considerable interest due to their improved mechanical properties and durability. However, most research is focused on the macroscale performance of these composites with very little experimental and modelling research on the characterization of their nanoscale behavior. This makes the design of these new GO-cementitious composites challenging. In this paper, we present a novel molecular dynamics (MD) model for GO-cementitious nanocomposites to understand their behavior and predict their mechanical and fracture properties. In this model, different numbers of GO nanoplatelets were inserted into the C-S-H structure and a number of nanoscale mechanical parameters and crack bridging mechanism were obtained. The MD simulation results revealed that the addition of GO sheets increased the tensile and compressive strength of C-S-H by roughly 50% and 100%. The MD simulation results also identified a double-peak phenomenon which is an indication of additional plasticity when the intercalated GO/C-S-H structures are subjected to compressive stress. The fracture simulation results showed that the failure mode of the intercalated GO/C-S-H composites was marked by high energy release. The results of fracture simulations with different notch lengths also indicated that the addition of GO could improve the fracture performance due to a good interfacial connection between the GO and the C-S-H gel.