Study of mechanical properties and early-stage deformation properties of graphene-modified cement-based materials

The subject of the study was the possibility of graphene improving the mechanical and crack resistance of cement-based materials. Graphene was dispersed and incorporated into cement-based materials. The flexural strength, compressive strength, splitting tensile strength, stress-strain relationship, vickers microhardness, and rheological properties of composites prepared were tested to study mechanical properties. Furthermore, the deformation properties were tested by measuring autogenous and drying shrinkages. The test results indicated that incorporating graphene increased the cement paste's viscosity while the effect of graphene content on the viscosity of cement paste is not obvious. The shear stress of cement paste demonstrated a good linear relationship with the shear rate, indicating that the cement paste conformed to the Bingham fluid model. The incorporation of an appropriate amount of graphene enhanced the macro-mechanical properties of cement-based materials. For instance, when the graphene amount was 0.06 wt% of cement mass, the compressive and flexural strength increased by 10%. Graphene could enhance the micro-mechanical properties of cement-based materials. When the graphene amount was 0.06 wt%, it could increase the vickers microhardness by 8.6%. Furthermore, the elastic modulus of cement-based materials could be affected by incorporating graphene. When the incorporated amount of graphene reached 0.09 wt%, the elastic modulus could increase to more than 20%. Besides, incorporating an appropriate amount of graphene had a good inhibition effect on the autogenous shrinkage and drying shrinkage of cement-based materials. When the graphene amount was 0.06 wt%, the shrinkage performance of graphene-modified cement-based materials has an optimal increase rate close to 30%. (C) 2020 Elsevier Ltd. All rights reserved.