Reinforcing Mechanisms of Graphene-Oxide-Coated-Supplementary Cementitious Materials for High-Value Applications in Cement Industry: A Molecular Dynamics Investigation

The powder coating method opens a pathway for both graphene oxide (GO) dispersion and reutilization of supplementary cementitious materials (SCM) to prepare high-performance, low-carbon, and cost-effective cementitious materials. However, the selection of the coating SCM is crucial for the reinforcing effects of GO in cementitious composites. In the present study, three typical SCMs, recycled cement powder (RCP), fly ash (FA), and silicon dioxide (SiO 2 ), are selected as the coated particles to investigate the reinforcing mechanisms of the GO-coated-SCM modified cementitious composites via the molecular dynamic tensile simulation. The results demonstrate that the reinforcing effects of GO are highly dependent on its interface compatibility with SCM, directly related to GO’s physical anchoring ability and interface bonding strength on the SCM surface. In the RCP-OPC system, the coated GO enables the peak stress to reach 1.13 GPa, which is 74% higher than that of the unmodified system, and the strain energy density is increased by 89%. Compared with the FA-OPC and SiO 2 –OPC system, the enhancement ratio of composites by GO has improved by −62 to 56%. The strain and stress distribution characteristics further reveal that the introduction of GO significantly improves the stress transmission path and strain distribution pattern within the composite material. Reasonable coating can transfer the damage of composites from the OPC/SCM interface to the material matrix, thereby significantly improving the mechanical properties of the composite cement-based materials. The findings of this study not only broaden the mechanisms of GO on cementitious materials reinforcement but also provide theoretical support for the high-value application of SCM in the cement industry. Meanwhile, in this study, the synergistic application of GO and SCM elevates the replacement ratio of SCM in cementitious materials, advances the development of sustainable cementitious materials, and facilitates the construction of low-carbon and resource-conserving buildings.