This study investigates the viability of incorporating high doses of recycled tire steel fibers (RSFs) in concrete to enhance sustainability. To address this, RSFs are incorporated at volume fractions ranging from 1% to 1.75% in the concrete mixture. The study evaluates various performance parameters, including workability, elastic modulus, compressive strength (CS), split tensile strength (SS), flexural strength (FS), linear shrinkage (LS), and water absorption (WA). Results show a 10% improvement in SS and a 4% improvement in FS compared to plain concrete (0RFRC). Additionally, RSF-reinforced concrete (RFRC) exhibits a maximum 15% reduction in LS. Water absorption slightly increases, and adverse effects on CS and workability are noted with high RSF doses. RFRC can impact the cost of rigid pavements due to reduced depth requirements. Disposing of discarded tires and their by-products has emerged as a substantial environmental challenge, obstructing progress toward achieving net-zero targets. As a sustainable solution, this study explores the potential utilization of secondary materials derived from discarded tires within the construction industry. In conclusion, this research highlights the significant potential of utilizing RSFs to enhance the sustainability of infrastructure and contribute to more eco-friendly construction practices.

Currently, is observing a huge increase in waste tires in the world. Over 1 billion waste tires increase yearly, bringing environmental and health issues. Material recovery of particular waste allows for obtaining recycled steel fibers (RSF). RSFs incorporated in concrete significantly improve recycled steel fiber reinforced concrete's tensile strength and energy absorption (RSFRC). The goal of the experimental research presented in this paper is to investigate the compressive strength of RSFRC, tensile splitting strength and to determine particular fracture mechanical parameters of RSFRC with different doses of RSF. RSFRC compressive strength tests were carried out on three samples for each batch of RSF according to STN EN 12 390-3. Determination of tensile splitting was executed according standard STN EN 12390-6 in case three specimens, cilinders in shape. Selected fracture mechanical properties were determined on three RSFRC beams with a notch for each batch of RSF according to JCI-S-001-2003 and JCI-S-002-2003. Experimental research has shown that with a dose RSF higher than 1.9% by volume an increase in RSFRC compressive strength was observed. Further was invented, that with increase dosage of RSF increase tensile splitting strength of concrete. The bending test result is an increasing trend of fracture energy with an increasing dose of RSF. From this experimental research, it emerged that it is necessary to choose a dose of RSF of at least 1.9% by volume.

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.