Kirigami structure reinforcing the tensile performance of the graphene oxide calcium silicate hydrate composites

Abstract

Graphene oxide (GO) can enhance cement composites by promoting the hydration reaction and acting as bridging roles in hardened calcium silicate hydrate (C-S-H) gel. However, GO's high elastic modulus difference with C-S-H limits its full bridging effect. In this study, the kirigami structure is applied to substantially reduce the elastic modulus of GO. Via molecular dynamic (MD) simulation, the tensile properties of C-S-H/graphene kirigami (GK) composites are investigated and the corresponding reinforcement mechanism of GK is reported. The result indicates that GK can significantly enhance the ductility and delay the failure of the composites, increasing the strain energy density by about 34 % compared with C-S-H/GO. During the tensile destruction processes, GK could play a bridging role not only further improving the ductility of C-S-H matrix but also increasing the destructive energy, nearly 17–27 % compared to C-S-H/GO composite. Finally, the bridging enhancement theory revealed that the kirigami structure can significantly increase the strain energy density of nanosheets under tensile failure, and extend the bridging effect of nanosheets in composites. The findings of this work will not only deepen the understanding of the nanomodification cement mechanisms but also propose an innovative method for cementitious composites to control crack propagation and enhance durability.