Characterization of self-repairing performance and thermodynamic study of the SiO2-CaCO3 supported graphene oxide in cement composites

Nano-SiO 2 and CaCO 3 used as supporting material of GO (graphene oxide) and the SiO 2 -CaCO 3 -GO (SCG) was prepared, the self-repairing performance of the cement under the effect of the SCG were studied, the thermodynamic parameter of the cement were analyzed for the understanding of the SCG on the hydration behavior of the cement. The results showed that the mechanical properties of cement composites were improved, the cement composites had the compressive strength repair rate of up to 7.4 % as the addition of SCG, the surface cracks repair rate reached 100 %, which showed an obvious repairing effect than the control specimen. TG analysis showed that GO promoted the pozzolanic reaction between the nano-SiO 2 and Ca(OH) 2 , SEM analysis showed that the interface between SCG and cement was gradually disappeared as the improved content of GO in SCG, indicating a good nucleation effect of GO in the cement hydration. ICP-AES test and the thermodynamic study showed that SCG continuously provided a greater dissolution driving force for the dissolution of calcium silicate minerals CS (C 3 S/C 2 S), results in the generation of more and denser C-S-H gel in the cement composites.