Influence of strain rate on bond behavior of concrete members reinforced with basalt fiber-reinforced polymer rebars

Abstract

Fiber-reinforced polymer (FRP) rebars are utilized extensively in reinforced concrete structures because of advantageous mechanical and physical properties. The bond behavior of concrete members reinforced with FRP rebars is essential to evaluate the load carrying capacity of concrete members. Although the bond behavior of concrete members reinforced with FRP rebars under static loading has been studied, research studies on the bond behavior of concrete members reinforced with basalt FRP (BFRP) rebars under dynamic loading are still lacking. The bond behaviors of concrete members reinforced with BFRP rebars under different strain rates were investigated. Test results and corresponding analysis showed that: (1) three bond failure modes of concrete members reinforced with BFRP rebars under dynamic loading were observed: crushing of concrete, bond failure at interface between resin and concrete, and bond failure at interface between fiber and resin; (2) the bond strength of concrete members reinforced with BFRP rebars increased as the strain rates increased and a model for bond strength was proposed considering strain rate; (3) the slip corresponding to bond strength decreased as the strain rates increased and a model for the slip corresponding to bond strength of concrete members reinforced with BFRP rebars was proposed considering strain rate; (4) a prediction model for bond stress-slip relationship of concrete members reinforced with BFRP rebars considering strain rate was proposed based on the BPE model which considers concrete cover, transverse confinement, steel rebar spacing and compressive strength of concrete, etc.. The proposed model showed good correlation with experimental results.