In many applications, particularly in pavements, bridge deck overlays, and offshore structures, the flexural fatigue strength and endurance limit are important design parameters because these structures are designed on the basis of fatigue load cycles. This paper presents the results of an extensive experimental investigation to determine the behaviour and performance characteristics of the most commonly used fiber reinforced concretes (FRC) subjected to fatigue loading. A comparative evaluation of fatigue properties is presented for concretes with and without four types of fibers (hooked-end steel, straight steel, corrugated steel, and polypropylene) at two different quantities (0.5 And 1.0% By volume), using the same basic mix proportions for all concretes. The test program involved the determination of fresh concrete properties, including slump, vebe time, inverted cone time, air content, unit weight, and concrete temperature; and the determination of hardened concrete properties, including flexural fatigue strength, endurance limit, and impact strength. The addition of the four types of fibers caused a considerable increase in the flexural fatigue strength and the endurance limit for 4 million cycles, with the hooked-end steel fiber providing the highest improvement (143%) and the straight steel and polypropylene fibers providing the least. The impact strength was increased substantially by the addition of all four types of fibers, with straight steel fiber producing the lowest increase.
Abstract