▎ 摘　　要

Recently, graphene oxide (GO) is one of the nanomaterials that enhance the performance of cement-based materials. In this paper, the effects of different mass of GO on the workability and mechanical properties of UHPC is studied, and its mechanism is explored by micro-nano analysis methods such as XRD, SEM, MIP and nano indentation. The results show that, compared with the reference group, the 0.04% GO addition reduces the fluidity of UHPC, reduces the initial and final setting time of slurry, and enhance the compressive strength, flexural strength and tensile strength of the sample at 28d by 15.8%, 14% and 15.3%, respectively. Micro-nano analysis results show that GO promotes cement hydration, reduces the porosity of UHPC, improves the microstructure of the interface transition zone between steel fiber and matrix, and improves the nano-mechanical properties. This is mainly attributed to the nucleation effect of GO and interfacial bonding with C-S-H gel.