グラフェン酸化物修飾CSHの凍結融解サイクルに対する特性の分子動力学研究

Microstructural damage from freeze-thaw cycles severely undermines the durability of cementitious materials. Although graphene oxide (GO) is known to refine cement microstructures, its molecular mechanism for enhancing frost resistance remains unclear. This study employed molecular dynamics (MD) to investigate the effect of GO on the properties of calcium silicate hydrate (CSH) under freeze-thaw cycles. Simulation results demonstrated that GO forms strong bonds with the CSH matrix, leading to a densified interfacial structure. Atomic-scale analysis revealed that GO stabilizes the hydrogen-bonding network within CSH. Consequently, GO mitigates the degradation of peak compressive stress and elasticity modulus relative to neat CSH under the same freeze-thaw protocol. As a result, the overall damage tolerance of the composite is enhanced. This study elucidates the mechanism behind the enhanced frost resistance of GO-modified cement mortar at the molecular level and provides theoretical support for research on the durability of nano-modified cementitious materials.

All MD simulations were conducted using LAMMPS. The models employed ReaxFF force field. To simulate the freeze-thaw damage mechanism in cementitious materials, a cyclic strain with a maximum amplitude of 0.15 was applied along the Z-axis of the CSH model.