Abstract Ultra‐high performance fiber‐reinforced concrete (UHPFRC) has great potential for structural applications involving precast cylindrical shapes, including pipes, silos and stay‐in‐place forms for concrete columns. This study examines the performance of UHPFRC rings under internal pressure simulated using the split‐disk loading method, along with digital image correlation (DIC) to capture the continuous strain field. Thirty rings extracted from precast tubes were tested to examine the effects of fiber type, namely polyoxymethylene (POM) and steel fibers, and fiber content of 0%, 1%, and 2.5% by volume. The study also examined the effect of adding internal steel wire mesh of 1.07% circumferential reinforcement ratio, placed at mid‐thickness. It was shown that while steel fibers enhanced tensile strength, POM fibers did not. Adding 1% and 2.5% POM fibers decreased load capacity by 19% and 15%, respectively, while the same amounts of steel fibers increased load capacity by 38% and 115%, respectively. Both fiber types, however, improved circumferential stiffness. In presence of steel mesh reinforcement, both fiber types increased load capacity. The 2.5% steel fibers sample without steel mesh achieved tensile capacity that is 31% higher than that of a sample with 1.07% steel mesh only and no fibers. Overall, steel fibers significantly enhance the tensile capacity of UHPFRC rings and may partially or fully substitute conventional steel mesh reinforcement, whereas POM fibers primarily improve stiffness and post‐cracking deformation capacity without contributing to tensile strength. Models that do not account for steel fiber percentage underestimate tensile strength. A new model is proposed to better account for steel fiber percentage.
Fakeh et al. (Thu,) studied this question.