Tensile Fracture and Bond Properties of Ductile Hybrid FRP Reinforcing Bars

Fibre reinforced plastic (FRP) rebar has only linear elastic behaviour, whereas steel rebar has linear elastic behaviour up to its yield point, followed by a large amount of plastic deformation. With no plastic deformation, a small increase in the load acting on concrete structures containing FRP rebar can cause a catastrophic collapse without warning. A ductile hybrid FRP rebar was manufactured and evaluated in this study. The tensile and bond strengths of the hybrid FRP rebar were tested to determine its fracture properties and bond behaviour. It showed elastic behaviour up to the point of early fracture, but had very irregular behaviour thereafter. The fibres in the sleeves were broken at very irregular lengths, while the cores appeared to fracture in a regular pattern. The stress–strain curves were linearly elastic, with a definite yield point followed by pseudo-plastic deformation. In addition, the hybrid rebar specimens exhibited a large amount of slip when the peak load was reached.