Effect of reinforcement ratio on flexural behavior of I-shaped UHPFRC beams

Abstract

This study aimed to investigate the effects of reinforcement ratio on flexural behavior of I-shaped Ultra High Performance Fiber Reinforced Concrete (UHPFRC) beams. In this framework, the total of four full-scale test beams with different reinforcement ratios were cast using a UHPFRC mixture consisting of high strength steel fibers and were tested under four-point flexural loading. The flexural behavior was evaluated in terms of load-midspan deflection relationship, deflection ductility, load carrying capacity, failure mode and cracking pattern. Additionally, the experimental results of this study were compared with another research on UHPFRC beams to examine the effects of different fiber type on flexural behavior. In the beams with short steel fiber, while the amount of reinforcement slightly increased the initial stiffness, the load carrying capacity was significantly improved with the increase in reinforcement ratio. In addition, an increase in the reinforcement ratio led to an apparent increasing trend in the deflection ductility. The fiber type comparisons showed that short straight fibers are more efficient than hooked fibers in preventing inclined cracks as well as the improving load capacity.