Hydration kinetics, pore structure, 3D network calcium silicate hydrate, and mechanical behavior of graphene oxide reinforced cement composites

•The effects of PC modified GO on the hydration kinetics, pore structure and C-S-H gels were systematically investigated by a combination of isothermal calorimeter, MIP, nitrogen isotherm adsorption analysis, XPS, and NMR.•NMR results showned that the polymerization degree of C-S-H gels was increased with the incorporation of GO.•A 3D network structure of GO modified C-S-H gels was originally proposed that GO intercalated into the interlayer space of C-S-H gels through ionic bonding with Ca2+ and filled in the gel pores. The effects of graphene oxide (GO) on the hydration kinetics, pore structure, mechanical properties, and the structure of calcium silicate hydrate (C-S-H) gels were systematically investigated by combinatorial techniques. GO can accelerate the cement hydration, refine the pore structure and increase the polymerization degree of C-S-H gels due to the nucleation effects of GO. The specific surface area of cement paste and the number of gel pores were reduced with the addition of GO. A 3D network structure of GO modified C-S-H gels was originally proposed based on the obtained results that GO could intercalate into the interlayer space of C-S-H gels through ionic bonding with Ca2+ and fill in the gel pores. A small fraction of GO (0.022 wt%) increased the 28 d compressive strength by 16.31%–25.60% at a various water to cement ratios, indicating that GO is a potential nano-reinforcing material for cement composites. The results would provide a well understanding of the reinforcing mechanisms of GO in cement composites and pave a pathway for the design of high-performance cement composites.