Durability of graphene-modified epoxy vinyl resin served as matrix phase of composite bar in simulated concrete environment

The polymer resin is usually used as an adhesive for repairing and strengthening concrete structures or served as the matrix phase of composite bar. Because the alkaline environment of concrete makes polymer resin degradation with time, the toughening modification of polymer resin has great significance. Herein, the effects of nanofiller content and exposure time on the durability of graphene-modified epoxy vinyl resin in the simulated ordinary concrete environment were evaluated by the accelerated aging method at 60 °C. The results indicated that the addition of 0.3 wt% graphene made the tensile, compressive, flexural strengths and fracture toughness of epoxy vinyl resin samples improve by 18.5%, 2.6%, 29.7% and 22.1% compared to the plain resin samples, respectively. Meanwhile, a novel multi-stage compressive constitutive model was proposed to describe the stress-strain response of polymer-based composite. Additionally, a series of tests illustrated that the durability of graphene-modified epoxy vinyl resin samples was enhanced after exposure to the simulated concrete environment. The degradation degrees of tensile, compressive, flexural strength and fracture toughness of the samples with a 0.3 wt% incorporating content of graphene declined by 7.9%, 10.4%, 5.5% and 10.4% after twenty-eight days of exposure compared to those of the exposed plain resin samples, respectively.