Impact of graphene oxide on the hydration process and structural evolution of calcium silicate hydrate in cement-based materials: A molecular dynamics study

The hydration of calcium silicate hydrate (CSH) is crucial in determining the mechanical properties and durability of cement-based materials. In this study, we investigate the impact of graphene oxide (GO) on the hydration process of CSH using molecular dynamics simulations. The primary focus is on how GO influences the nucleation, ion distribution, and structural evolution of CSH gels during cement hydration. The results reveal that GO significantly accelerates the nucleation process, especially in the formation of short-chain and long-chain CSH structures, through its oxidized functional groups, which interact with calcium ions (Ca 2+ ) and promote their aggregation. GO’s presence alters the distribution of Ca 2+ and silicon atoms, with a more pronounced effect on Ca 2+ ions, leading to localized high-concentration regions and enhancing the nucleation process. In contrast, Si atoms exhibit a more uniform distribution in the system, indicating a weaker adsorption effect. Additionally, GO improves the structural ordering of Si-O bonds in CSH, which accelerates the formation of CSH gels, although it has minimal impact on the bond angle distribution. Overall, GO acts as a heterogeneous nucleation agent, increasing the number and density of nucleation sites, thus improving the early-stage hydration process, microstructure, and potentially the mechanical properties and durability of cement-based materials. The findings provide valuable insights into the role of GO in enhancing cement hydration, offering a promising approach to improving the performance of cement-based materials in construction.