Study on the three dimensional mechanism of graphene oxide nanosheets modified cement

•The first discovery of the 3D network structure of GO nanosheets in cement system.•First demonstration of the chemical reactions between GO and hydration products.•Provide a new direction of GO nanosheets were used for improving cement properties.

This paper has established a 3D mechanism model of graphene oxide (GO) nanosheets modified cement. The GO nanosheets were compounded by the improved Hummers' method and characterized by Fourier transform infrared spectroscope (FTIR), transmission electron microscope (TEM) and atomic force microscope (AFM). The mechanism of GO nanosheets modified cement was investigated by scanning electron microscope (SEM), differential scanning calorimeter (DSC), thermogravimetric analysis (TGA), FTIR and X-ray photoelectron spectroscope (XPS). Based on these analyses, it was confirmed that the -COOH in the GO nanosheets reacted with the hydration product of cement (Ca(OH)2). The chemical reactions connected the GO nanosheets each other, producing a 3D network structure in the GO nanosheets modified cement. Moreover, the hydration products were also inserted into this 3D network structure. Therefore, the introduction of GO nanosheets improved the mechanical properties of cement composites.