▎ 摘　　要

The enhancement of mechanical properties of cement composites by a carbon nanomaterial is an important topic. However, the co-effect of two (or more) carbon nanomaterials on the mechanical properties of cement has not been explored. In this paper, it was found that the mixture of graphene oxide (GO) sheets and single-walled carbon nanotubes (SWCNTs) exhibited an excellent co-effect, leading to 72.7% increase in bending strength of cement, which is much larger than the strength enhancements of 51.2% by GO and 263% by SWCNTs. Furthermore, it was demonstrated that the bending strength of cement composite materials with GO and SWCNTs is proportional to the sizes of crystal SiO2 particles. (C) 2015 Elsevier Ltd. All rights reserved.