Interfacial mechanics of steel fibers in a High-Strength Fiber-Reinforced Self Compacting Concrete

The work in hand reports an experimental work on the pullout behavior of hooked-end, half-hooked and straight steel fibers from a High-Strength Fiber-Reinforced Self-Compacting Concrete (HSFRSCC). The influence of three matrix fiber contents on pullout was investigated and compared to an unreinforced control matrix. It was found that half-hooked fibers had the best capacity during the friction regime and can dissipate more energy than hooked-end fibers. Also, the presence of fibers in the matrix had the most beneficial effect on the composite with a fiber content of 0.75%, explained by the improved confinement of the reinforced matrix, fiber to fiber interlock, and better control of splitting cracks for fiber with mechanical anchorage. Further increase in fiber content (V_f = 1%) had a deleterious effect reducing the bond performance. In General, the half-hooked fibers were the only ones presenting better dissipation capacity than the unreinforced matrix. There was no evidence that the increase in embedment length increases the pullout load.