DEVELOPMENT OF BASALT FIBRE REINFORCED POLYMER (BFRP) REBAR INFUSED WITH GEOPOLYMER BINDER

In order to mitigate the corrosion issue of steel reinforcement in concrete structures, various protective schemes, such as increasing concrete cover, coating steel rebars and reducing the permeability of concrete, were implemented in the past. While these schemes can delay the corrosion process, rehabilitation and maintenance cost associated with corrosion remain significant. Due to the non-corrosive nature, non-conductivity and higher tensile strength, various types of fibre reinforced polymer (FRP) rebar are increasingly being used in concrete structures targeting a longer service life with reduced maintenance cost. Even though FRP rebars possess numerous advantages over steel rebars, the modulus of elasticity, bond strength and thermal resistance 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-compatitility between inorganic concret and organic polymer from FRP leads to poor interfical bonding. These shortcomings of FRP rebars limit their use in some concrete structures. Also, the failure of FRP rebar in a brittle manner limits its application in concrete structures in earthquake prone zone and/or concrete frame subjected to wind. This study developed basalt FRP (BFRP) rebars by impregnating BFRP fibre tows with a hybrid binder made of geopolymer and epoxy resin and investigated the properties of the geopolymer BFRP rebars under compression and tension. Fly ash and slag, along with NaOH and Na2 SiO3 as activators, were used to develop the geopolymer binder. Epoxy resin (approximately 32% by weight) was added to the geopolymer mix to improve the cohesiveness and viscosity of the binder composite. A total of 5 geopolymer BFRP rebars of 12 mm diameter and 500 mm length were produced and tested. Results show that the developed geopolymer BFRP rebars attained an average compressive and tensile strength of 155 and 320 MPa, respectively, which are around 63% of the compressive strength and 56% of the tensile strength of 500-grade steel rebars.