Comparison of the mechanical characteristics of engineered and waste steel fiber used as reinforcement for concrete

Engineered steel fiber has been used for reinforcing concrete since the mid-nineteenth century. The influence of fiber reinforcement on the mechanical characteristics of concrete is commonly known and thoroughly described in literature. The fast growing and vibrant market of engineered steel fiber is increasingly disrupted by waste steel fiber obtained during recycling of tires. The lack of knowledge about properties of the waste steel fiber significantly limits its technically viable use. The main aim of the conducted research program was to test waste steel fiber and to compare its properties with most popular engineered steel fiber. Such properties as tensile strength estimated according to EN ISO 6892-1:2009, ductility tested according to EN 10218-1:1994, and tensile strength after ductility test were considered. Waste steel fiber proved to be characterized by much higher tensile strength and ductility than engineered steel fiber. Stress-strain characteristics of both the types of fiber also differ significantly. Conducted bends influence the tensile strength and modulus of elasticity of all tested waste and engineered steel fiber. The achieved knowledge would allow to create sustainable steel fiber-reinforced concretes in a much more efficient way.