Properties of Concrete with Dosages of Recycled and Industrial Steel Fibers

Currently, there is a significant increase in the number of waste tires in the world. An increase of 1 billion waste tires occurs yearly and consequently results in environmental and health issues. The recovery of material from waste tires includes recycled steel fibers (RSF). RSFs incorporated in concrete significantly improve the tensile strength and energy absorption (RSFRC) of reinforced concrete. The goal of the experimental research presented in this paper is to investigate the workability of fresh concrete with steel fibers as well as the mechanical properties (compressive strength, flexural strength, and fracture energy) of concrete hardened with steel fibers. Experimental research has shown that with a dose of steel fibers, only a slight increase in compressive strength can be observed. Nevertheless, a significant increase in slump value, tensile strength, and fracture energy was observed. The most significant improvement in the relevant concrete parameters was observed with industrial fibers. Still, recycled steel fibers could potentially be a sustainable option for selected fiber-reinforced concrete applications.