Fiber fraction-dependent flexural behavior of high-performance fiber-reinforced concrete under static and repeated loading

Abstract

The effect of the fiber volume fraction on the flexural behavior of high-performance fiber-reinforced concrete (HPFRC) under both static and repeated loading is highlighted through a series of experiments. All rectangular prism-shaped flexural specimens were 40 × 40 × 160 mm3 and subjected to a three-point bending (3 PB) fixture with a span length of 120 mm. Macro-hooked and micro-smooth steel fibers with volume contents of 0.0%, 0.5%, 1.0%, and 1.5% were investigated. The flexural strength and deflection capacity of the HPFRCs under static loading generally increased with increasing fiber volume content. The micro-smooth fiber mostly produced a higher flexural strength and a lower deflection capacity compared to the macro-hooked fiber. Under repeated loading, a larger fiber volume fraction generally resulted in higher HPFRC endurance limits, which exceeded 40,000 cycles with a fatigue stress ratio of <0.5, at a fiber volume fraction of 1.5 vol%. The flexural fatigue equations of the HPFRCs of various fiber contents were calculated with the fatigue stress amplitude as well as the fatigue stress ratio, based on the experimental data. The HPFRCs’ sensitivity to endurance limits generally decreased with increasing fiber content; this finding was greater when using the micro-smooth fiber than when using the macro-hooked fiber.