Influence of rib parameters on mechanical properties and bond behavior in concrete of fiber-reinforced polymer rebar

Mechanical properties of fiber-reinforced polymer rebar and bond behavior between the fiber-reinforced polymer rebar and concrete are highly related to rib parameters, including rib depth and rib spacing. Therefore, rib parameters should be taken into account when fiber-reinforced polymer bars are used as the structure reinforcement. In this article, the tensile properties of glass-fiber-reinforced polymer rebars with different rib depths and rib spacings are tested. The influences of different rib depths and rib spacings on the bond behavior between glass-fiber-reinforced polymer rebar and concrete are investigated by pull-out test. Experimental results show that the rib depth has a distinctive effect on the ultimate tensile strength, elastic modulus, and ultimate elongation of glass-fiber-reinforced polymer rebar. The tensile strength and elastic modulus of glass-fiber-reinforced polymer rebar with shallow rib are remarkably higher than those of glass-fiber-reinforced polymer bars with deep rib. However, compared with the glass-fiber-reinforced polymer bars with shallow rib, the glass-fiber-reinforced polymer bars with deep rib contribute larger bond strength with concrete. Besides, the bond strength and basic anchorage length are predicted by taking rib depth and rib spacing into account. A modified Bertero–Popov–Eligehausen model is adopted to simulate the bond stress–slip behavior, and the ascending branch of bond stress–slip curve expressed by rib depth and rib spacing is also proposed. The calculated results are in good agreement with the test ones.