Bond behavior between basalt fiber-reinforced polymer bars and concrete under cyclic loading

Abstract

Concrete structures reinforced with fiber-reinforced polymer (FRP) bars are frequently subjected to cyclic loadings. The bond behavior between FRP bars and concrete under cyclic loading is important in evaluating the seismic and fatigue performance of concrete structures reinforced with FRP bars. Although the bond stress-slip relationship between basalt FRP (BFRP) bars and concrete under static loading has been investigated, investigations on the bond behavior between BFRP bars and concrete under cyclic loading remain lacking. The present study presented experimental investigations on the bond behavior between BFRP bars and concrete under cyclic loading using a pull-out test. Test results showed that: (1) the bond stress-slip relationship between BFRP bars and concrete revealed the behavior at different phases: the elastic phase, the cracking propagation phase, the cracking closure phase, and the friction phase; (2) the bond strength between BFRP bars and concrete under cyclic loading decreased with the increase of number of cycles; (3) the slip corresponding to bond strength between BFRP bars and concrete under cyclic loading increased with the increase of number of cycles; (4) the hysteretic curve area between BFRP bars and concrete under cyclic loading decreased with the increase of number of cycles; (5) several prediction models for bond strength, slip corresponding to bond strength and hysteretic curve area between BFRP bars and concrete under cyclic loading were proposed considering number of cycles; (6) the residual bond strength between BFRP bars and concrete decreased while the slip corresponding to residual bond strength increased after cyclic loading.