▎ 摘　　要

The current study presents a new idea for reinforcing the cement and its realization. The idea includes the increase of the surface roughness of the graphene oxide (GO) sheets through their decoration by nanoparticles, which enhances the interaction between filler and cement matrix. To reinforce the cement, the GO-Fe3O4 hybrid nanocomposite were prepared by electrostatic attraction approach. The hybrid filler was added to the cement paste with different graphene content. The performance of the composite materials were evaluated in different aspects. It was revealed that the sample containing 0.25 wt% Fe3O4 and 0.05 wt% GO (FG5) exhibited the best physical and mechanical behaviors. The FG5 sample showed an increase in compressive, flexural, and tensile strengths by 53, 94, and 86%, respectively, in comparison with those of the plain cement sample after 28 days of hydration. In addition, 148% growth for the toughness and 31% reduction for the total porosity of this sample compared to those of the neat cement sample were obtained. The XRD and morphological results for the cement containing GO-Fe3O4 nanocomposite indicated the formation of a denser, more integrated structure. (C) 2020 Elsevier Ltd. All rights reserved.