The Effect of Steel Fibers on the Interlocking Length between Reinforcement and Concrete and on Compressive Strength of Concrete

The use of steel fibers in a certain ratio in the concrete mixture can provide more energy dissipation to transitioning the concrete from a brittle material to a ductile material. The effects of steel fibers on the interlocking force behavior between concrete and reinforcement, as well as on concrete compressive strength, were investigated experimentally in this study. Two different water/cement ratios were prepared in the concrete mixtures for the creation of concrete samples. In the preparation of concrete, the volume of steel fibers was treated as 0.00%, 0.25%, 0.50%, and 1.00%. To evaluate the effects of steel fibers on the interlocking force between reinforcement and concrete, ribbed steel reinforcement bars were embedded by fastening the samples vertically at interlocking lengths of 5 cm, 10 cm, and 15 cm during casting. Pull-out tests and concrete compression tests were performed on the concrete samples that had been cured for 28 days. As a result of the increase in steel fiber volumetric ratios from 0.25% to 1.00%, the compressive strength increased and it was found out that the steel fibers contribute negatively to the increase in compressive strength. Nevertheless, the tensile strength increases in parallel with the increase in interlocking length between concrete and reinforcement, but the tensile strength of the steel fiber samples is generally lower than that of nonfibrous samples. The principal findings of this study demonstrate that the steel fibers have a beneficial effect on flexural behavior, cracking performance, and postcracking residual stresses.