Fiber Orientation Effect on Flexural Response of UHPFRC

This study aims to examine the fiber orientation effect on flexural behavior of ultra-high-performance fiber-reinforced concrete (UHPFRC) with various casting methods and loading rates. For this, two different placement methods were adopted for making UHPFRC beams along with two different loading rates (i.e., quasi-static and impact). Test results indicated that the flexural performance of UHPFRC beams at both quasi-static and impact loads was significantly influenced by the placement method, leading to dissimilar fiber orientation. Better fiber orientation, denoting that more fibers are aligned in the direction of tensile load, exhibited better post-cracking flexural behaviors in terms of flexural strength, deflection capacity, and toughness, compared to poor fiber orientation. Strength enhancement in UHPFRC beams was obtained by increasing the loading rates, and their deflection-hardening behaviors were successfully observed.