Microstructure and mechanical performance of graphene reinforced cementitious composites

An experimental investigation of the microstructure and mechanical properties of graphene-reinforced cementitious composites is presented. The early-age microstructure of the grapheme/cement composites was examined by scanning electron microscopy (SEM). The SEM images revealed that ettringite, C-S-H gel and other hydration crystals were connected by graphene sheets, which formed a 3-D structure that could bridge the cracks and fill the pores in cement matrix. With the increase of hydration ages, the 3-D structure became more complicated and connection between the graphene and cement hydrates became stronger. The X-ray powder diffraction (XRD) analysis suggested that the amount of ettringite increased with the increase of graphene content, indicating that graphene sheets could promote the formation of ettringite. In addition, the mechanical strength of graphene/cement matrix was measured. The reinforcing effect of graphene is most obvious with the addition of 0.03 wt.% graphene, with which the flexural strength increased by 40%.