Mechanical and durability-related performance of graphene/epoxy resin and epoxy resin enhanced OPC mortar

In this research, normal epoxy resin was reinforced by graphene nanosheets which was then used for improving mechanical properties and durability of ordinary Portland cement (OPC) mortars in terms of water sorptivity, resistance towards chloride penetration and freeze–thaw actions. Results showed that epoxy resin modified OPC mortar had a similar or lower compressive strength in the early curing ages whereas a higher one was obtained after 56 days of curing, especially for the mortar with the graphene addition. Flexural strength was all improved after the addition of epoxy resin, particularly for the graphene incorporated one. Besides, epoxy resin modified mortars were endowed with higher durability evidenced by lower capillary sorptivity and negligible mass loss and changes in relative dynamic modulus during freeze–thaw cycles, as compared to the normal OPC counterpart. With the addition of graphene, epoxy resin modified OPC mortar displayed an obvious lower chloride contents (especially at deeper depth) and capillary sorptivity. Microstructure analysis revealed that epoxy resin could refine the porous structure of the OPC mortar and graphene is able to enhance this benefit even further by densifying the mortar binding matrix. Considering the extremely small dosage of graphene but significant improvements in resistance against water ingress via capillary forces and chloride penetration, this novel method of combing graphene as a nanofiller with epoxy resin could be further utilised for OPC binders in practical aggressive engineering environments.