Experimental Study On Bending Behavior Of Reinforced Concrete Beams Strengthen By Hybrid Fiber

Fiber reinforced concrete is a effective way to improve the capability of ordinary reinforced concrete due to experimental study and engineering practice.For the finity of single fiber, it is a method to max two or two more type of fibers together to improve the capability of ordinary concrete if we want to get better capability. This paper study the bending capability of concrete beams reinforced by steel fiber and polypropylene fiber.Bending experiment on reinforced concrete beams strengthened by hybrid fiber have been done in this paper. From the experiment result, we get some conclusions as follows:1. The beams strengthen by hybrid fiber show better appearance quality, reduce honeycomb, pockmarked face, blowhole, tiny crack on beams surface.2. The beams strengthen by single fiber can improve cracking load. But the beams strengthen by hybrid fiber can improve cracking load in larger scale, and it increases with the hybrid fiber volume rate's addition, max to 125% compare with normal reinforced concrete.3. The beams strengthen by polypropylene fiber hardly can improve ultimate load. The beams strengthen by steel fiber can improve ultimate load more. But the beams strengthen by hybrid fiber can improve ultimate load in more larger scale, and it increases with the hybrid fiber volume rate's addition, max to 30.8% compare with normal reinforced concrete.4. From the load—displacement curves of experiment beams, the beams strengthen by hybrid fiber increase its stiffness and ductility, reduce its displacement.5. The cracks of the beams strengthen by hybrid fiber appear later, its spacing smaller, its width also smaller and its amount more.6. Based on normal reinforced concrete beam, bring forward the bending capacity formulation on the right section of hybrid fiber reinforced concrete beam.In the end of this paper, futher research work of hybrid fiber reinforced concrete are forecasted.