Mechanical behavior and toughening mechanism of polycarboxylate superplasticizer modified graphene oxide reinforced cement composites

Graphene oxide (GO) has attracted increasing interests for the use as nano-reinforcement in cement composites. However, the dispersion problem of GO nanosheets in alkaline cement matrix has been restricting its real application. In this paper, polycarboxylate superplasticizer (PC) modified GO (PC@GO)1 was used to improve the dispersion of GO and the mechanical behavior of cement composites. The results show that PC@GO disperses uniformly in alkaline cement matrix and exhibits reinforcing effects on mechanical behavior of cement composites. With the addition of ∼0.242 wt% PC@GO (PC 0.22 wt%, GO 0.022 wt%) of cement, the compressive strength, flexural strength, Young's modulus and flexural toughness can be increased to 34.10%, 30.37%, 32.37% and 33%, respectively at early days. The toughening mechanism of PC@GO is attributed to its resistance to the formation and growth of cracks based on the characterization of cracks in scanning electron microscope images. This work has opened an effective way to use GO as a nano-reinforcing material for cement composites.