Study on bond strength of geopolymer and control concrete between fiber-reinforced polymer and steel bars

Significant issue in reinforced concrete (RC) structures is corrosion of steel. High alkalization of cement matrix, low permeability, and sufficient cover plays an important role to shield from corrosion of steel. There is a replacement material for steel is fiber-reinforced polymer (FRP) bars as reinforcement. The FRP bars are nonconductive and durable material and they are composited from fibers and polymers matrix. In this study, new technology geopolymer concrete (GC) was used along with glass fiber-reinforced polymer (GFRP) and basalt fiber-reinforced polymer (BFRP) bars. GC is produced from industrial by-product materials such as fly ash and ground granulated blast furnace slag (rich in silica and alumina) and treated as sustainable material. The long term durability of many RC structures affects drastically by the reinforcement corrosion. Main aspect of bond behavior is tension stiffening as it has capability to control the reinforcement to shift the tensile stresses to concrete. This paper evaluates the bond strength between the GC reinforced with GFRP/BFRP and the results were evaluated with conventional concrete (CC) reinforced with steel. The pullout test method was used to determine the bond between FRP and steel bars with the surrounding concrete based on IS: 2770 (part I)-1967. The comparison of bond strength GC with FRP almost same as CC with steel. The tension test and double shear test were also carried out in FRP and steel bars based on IS 432-1982 and 5242-1979, respectively.