Flexural Performance of Hybrid Fiber-Reinforced Ultrahigh-Performance Concrete with Locally Available Materials

Recent studies have focused on investigating ultrahigh-performance fiber-reinforced concrete (UHPFRC) developed under normal conditions, but the majority involved the use of special filler aggregates. The effect of fibers, especially hybrid fibers, on the postcracking performance of UHPFRC developed under normal conditions has still not been investigated in depth. Toward this objective, this study investigated the behavior of a hybrid fiber mix in an optimized UHPFRC mix manufactured from locally sourced materials. Steel fibers, after being optimized by volume, were investigated for the effect of aspect ratio on the mechanical performance of developed UHPFRC. The UHPFRC with 3% hybrid fibers possesses high compressive strength (158.76 MPa), split tensile strength (26.52 MPa), and flexural strength (60.28 MPa). The hybridization of the fibers with low and high aspect ratio results in enhanced mechanical performance compared to a single aspect ratio. Long fibers lead to the highest toughness index of 32.60, followed by the hybridization of fibers at 24.95. Toughness indexes are also observed to be highest for long fibers and are comparable for hybrid fibers to reported valuable values. Hybridization of fibers leads to highest ductility indexes of 2.32 followed by long fibers at 2.13, indicating the energy dissipation capacity of normally developed UHPFRC is in good agreement with conventional UHPFRC.