Flexural Behavior of Polypropylene Fiber Reinforced Concrete Beams with Super elastic Wire Under Repeated Loading

Abstract

This paper investigates the effect of polypropylene fiber (PPM-12) and nitinol (NiTi) superelastic Shape Memory Alloy (SMA) wires in concrete beams under flexural repeated loading. For this purpose, nine of simply supported beams with dimensions of (1000 mm length, 80 mm width and 125 mm depth) were considered. Test specimens were divided into three groups (G1, G2 and G3). Specimens in group G2 and G3 were reinforced with different ratios of PPM-12 fiber (0.5%and 0.75%) by volume of concrete and threaded (NiTi) superelastic SMA wires. Group G1 was reinforced with traditional steel rebar and SMA wires without PPM-12 fiber. The results revealed that the addition of PPM-12 fiber to concrete have a negative effect on the mechanical properties of concrete with respect to load carrying capacity in the other side the addition of fiber led to a controlled crack propagation in concrete and increased the fatigue life of concrete. The (NiTi) superelastic threaded wires were active in some specimens in which some displacement recovery was noticed. The importance of study is how to enhance concrete life and reducing crack propagation in concrete by using polypropylene fiber and NiTi wire as reinforcement in concrete.