Flexural behavior and prediction models of hybrid fiber composite (HFC) rebar with tensile ductility

The influence of steel bar corrosion on the durability of structural concrete is increasingly becoming severe. It is urgent to develop a novel and excellent alternative to steel bar. Hybrid fiber composite (HFC) rebar with outstanding corrosion resistance and tensile ductility is considered as an ideal substitute for steel bar. In this work, the ductile carbon/glass (C/G) HFC rebars were designed and prepared, and then the flexural behavior was investigated under the three-point bending load. The effects of carbon/glass volume ratio ( V Carbon :V Glass from 0:1–1:4), fiber arrangement pattern (centralized and dispersed), fiber whole volume fraction ( V wf from 50% to 70%), and loading rate (from 3 mm/min to 15 mm/min) on the flexural behavior of ductile C/G-HFC rebar were analyzed and discussed. The microscopic morphology of fracture cross-section for monofilament fiber revealed that the failure mechanism of buckling and crushing for top fiber within the ductile C/G-HFC rebar under the three-point bending load. The outcomes demonstrated that the change of fiber arrangement pattern from centralized to dispersed made the flexural modulus and strength averagely go up by 27.24% and 29.62% for C/G-HFC rebars with V Carbon : V Glass ranging from 1:10–1:4, respectively. Ultimately, the superposition principle of fiber composite was proposed to predict the flexural modulus and strength of ductile C/G-HFC rebar, which considered the comprehensive reduction effect derived from manufacturing deficiencies.