Corrosion effects on mechanical behavior of steel fiber reinforced concrete, including fibers from recycled tires

Today, the use of special technologies in the admixture of concrete has made tremendous progress, but the problem that has always existed in the construction of concrete members is the brittleness and lack of loading bearing after cracking, which leads to reduced strength and energy absorption. One of the best ways to fix this is to reinforce the concrete with steel fibers. Steel fibers also control cracks due to dry shrinkage, reduce structural crack width, and improve impact resistance. In this study, recycled steel fibers from worn tires have been used in the manufacture of concrete samples, the secondary benefits of which are the reduction of environmental pollution. One of the disadvantages of steel fiber reinforced concrete is the corrosion of steel fibers and their deterioration in harsh environments such as coastal areas. Corrosion caused by chlorine ions in metal fibers causes deterioration and early decommissioning of structures in corrosive environments. In this study, the effect of the dosage of steel fibers (dosages of 15, 30, and 45 kg of fibers per cubic meter of concrete) and aspect ratio of fibers (aspect ratio of 25 and 50) on compressive and flexural strength of concrete samples are investigated. In the following, the effect of fiber corrosion on the results of the mechanical properties of concrete samples is examined. The results show that the increase in fiber causes a relative increase in compressive strength, and a significant increase in flexural strength, and corrosion of steel fibers without reducing workability reduces compressive strength and flexural strength by up to 6 to 11%, respectively.