Flexural behavior of expansive concrete beams reinforced with hybrid CFRP enclosure and steel rebars

To make full use of carbon fiber-reinforced polymer (CFRP) sheets and the advantages of prestressed structures, an expansive concrete beam reinforced with hybrid CFRP enclosure and steel is proposed in this study. Five expansive concrete (EC) beams and five conventional Portland cement concrete (PC) beams were tested under flexure. Reinforcement was designed by considering different layers of CFRP as well as steel reinforcement. Cracking loads, ultimate loads, mid-span deflections, and ductility were collected and analyzed. Test results show that beams reinforced with hybrid reinforcement perform superior than those reinforced only with steel in all aspects. The expansive concrete beams reinforced with hybrid reinforcement perform best among all in both mechanical properties and ductility. In addition, new equations were put forward for calculating the crack width of the beams reinforced with hybrid reinforcement and crack width-load relations are in good agreement with theoretical calculations.