Study on dispersion of graphene nanoplates and rheological properties, early hydration of cement composites

Graphene nanoplates (GNPs) own the growth-potential application in high performance composites materials, and its homogeneously dispersion shows a significant impact on properties of composites. In this paper, GNPs were highly dispersed in aqueous solution with dispersants and treated by ultra-sonication and then incorporated in cement composites. The dispersion effect of different dispersants with ultrasonic treatment on GNPs was represented by UV-absorbance. The effect of dispersion GNPs on rheological properties of GNPs/cement pastes were studied by viscometer. And the early hydration process analysis of GNPs/cement composites was monitored by isothermal calorimetry (TAM Air) and ²⁹Si NMR analysis. In addition, the microstructure and morphology of GNPs and cement composites were shown by SEM, which was the strong support of mechanism of GNPs dispersion in aqueous solution, and effect of dispersed GNPs on hydration and enhancement in cement composites. As a conclusion, GNPs can be dispersed uniformly in aqueous solution with the CO890 concentration of 0.7 g l⁻¹, and viscosity of GNPs/cement pastes decreased because of high specific surface area of GNPs. And early hydration process had been accelerated owning to the free ions exchange resulting from the high adsorption capacity of GNPs for calcium ions and more supererogatory reaction area of GNPs. (paper)