Axial compressive behavior of confined steel fiber reinforced high strength concrete

Concrete is brittle in nature which is why different materials have been used to improve this inherent behavior of concrete. In this experimental study, the effect of simultaneous use of steel fibers and confinement on high strength concrete and the corresponding post peak response of fiber reinforced concrete is investigated. A total of 39 high-strength concrete (incorporating varying amounts of steel fibers) cylinders were casted. The steel fiber volume fraction (V_f) was varied as 0.5%, 1.5% and 2.5%. 18 samples were confined with Carbon Fiber Reinforced Polymer (CFRP) sheet, and 9 samples were casted in steel pipe confinement, whereas 12 control specimens (without confinement) were also prepared. The samples were tested under axial compression. The results confirmed that the use of steel fiber had minute effect on the compressive strength, whereas it significantly improved the ductility and enhanced the post peak behavior of concrete. The confinement significantly contributed towards the compressive strength increase. The combined use of steel fibers and confinement in concrete columns can be viewed as extremely beneficial as it not only increases the concrete compressive strength but also solves the issue of brittle failure to an appreciable extent.