Enhancing the mechanical properties of calcium silicate hydrate by engineering graphene oxide structures via molecular dynamics simulations

It has been proved that the incorporation of graphene oxide (GO) can improve the mechanical and durability performance of cementitious matrix to varying degrees. However, it is unclear how defects, functional group content, and composition, as well as other factors, affect the enhancing effect of GO on the mechanical characteristics of calcium-silicate-hydrate (C-S-H). In this paper, molecular dynamics (MD) simulation is employed to engineer the mechanical properties of the GO/C-S-H composite. The effects of defect type and size, functional group content and composition on the mechanical properties of GO/C-S-H composite are investigated. The results show that (i) GO sheets with quadrilateral and hexagonal defects can effectively strengthen GO/C-S-H composites, but GO sheets with triangular defects cannot be enhanced. And the enhancement effect grows with the increase in defect sizes; The tensile strength of both perfect GO/C-S-H composites and defective GO/C-S-H composites increases significantly with increasing strain rate; (ii) increasing the functional group content of GO can improve the tensile strength of GO/C-S-H; (iii) the mechanical properties of GO/C-S-H composites can be tuned by changing the ratio of hydroxyl and epoxy groups. These findings inspire the optimal design of GO/C-S-H composites using nanotechnology.