Development of Basalt Fibre Reinforced Polymer (BFRP) Rebar Infused with Geopolymer Binder

Abstract

Due to the non-corrosive nature and high tensile strength, various types of fibre reinforced polymer (FRP) rebar are increasingly used in concrete structures targeting a longer service life with reduced maintenance cost. Even though FRP rebars possess numerous advantages over conventional steel rebars, the modulus of elasticity and bond strength of FRP rebars are significantly lower than that of the steel rebars, because these properties are mainly controlled by the properties of the resin system used to impregnate the fibres. Moreover, the nature of non-compatibility between inorganic concrete and organic polymer from FRP leads to poor interfacial bonding. Also, the failure of FRP rebar in a brittle manner limits its application in concrete structures subjected to lateral loads. These shortcomings of FRP rebars limit their use in some concrete structures. This study developed basalt FRP (BFRP) rebars by impregnating BFRP fibre with a hybrid binder made of geopolymer and epoxy resin and investigated the properties of the geopolymer BFRP (GP-BFRP) rebars under compression and tension. Fly ash and slag, with NaOH and Na2SiO3 as activators, were used to develop the geopolymer binder. Epoxy resin (ap-proximately 32% by weight) was added to the geopolymer mix to improve the cohesiveness and viscosity of the binder composite. A total of 5 GP-BFRP rebars were produced and test-ed. Results show that the developed GP-BFRP rebars attained an average compressive and tensile strength of 155 and 320 MPa, respectively, which are around 63% of the compressive and 56% of the tensile strength of 500-grade steel rebars.