Molecular dynamics study on the transport of water molecules and chloride ions in graphene oxide-modified cement composites

The ability of composite cement materials to resist erosion by chloride ions is a critical factor in evaluating their dependability. This study aims to examine the influence of graphene oxide on the transportation of water molecules and chloride ions in modified cement composites. Molecular dynamics analysis suggests that graphene oxide can effectively bond to the substrate of hydrated calcium silicate gel pores, which forms a stronger confined fluid zone under the action of electrostatic interactions and van der Waals forces. Graphene oxide has negatively charged oxygen functional groups on its surface, and within a certain size range, it becomes more effective at restricting the penetration of water molecules and chloride ions. In addition, chloride solution immersion experiments were performed on graphene oxide modified cement mortar. The results demonstrated that a small quantity of graphene oxide can significantly improve the resistance of modified cement mortar to chloride ion erosion, whereas excessive amounts are detrimental, which aligns with the simulation results. It is hoped that this study will provide valuable insights into the use of graphene oxide nanoparticles in the corrosion protection of cement composites.