Effect of bond length on bond behavior between basalt fiber-reinforced polymer sheet and concrete

Many reinforced concrete structures are always damaged due to material aging during service life. Reinforced concrete structures can be retrofitted by fiber-reinforced polymer (FRP) sheets to improve load carrying capacity and extend the service life. The bond behavior between the FRP sheet and concrete is important for assessing the load carrying capacity of reinforced concrete structures retrofitted with FRP sheets, and the effective bond length is often used in determining the bond behavior. Basalt FRP (BFRP) has excellent properties, such as light weight and high tensile strength. Although the effective bond length between carbon FRP sheets and concrete has been studied, study on the effective bond length between BFRP sheets and concrete remains lacking. The effect of bond lengths on the bond behavior between BFRP sheets and concrete was investigated in the present study. The results revealed that: (1) the failure load between the BFRP sheets and concrete increased with the increase of the bond length when the bond length was not beyond the effective bond length; (2) the effective bond length of the interface between BFRP sheet and concrete was not beyond 80 mm obtained from the failure load; (3) the effective bond length of the interface between BFRP sheet and concrete was obtained from the bond stress; and (4) models for the failure load and the effective bond length were established.