Assessing the impact of tire steel fibers on concrete’s fracture behavior, cracking resistance, and durability performance

The accumulation of waste tires in landfills poses a significant environmental challenge that requires innovative solutions, one of which involves incorporating tire components into concrete. Concrete reinforced with tire steel fibers (TF), TFRC, demonstrates enhanced properties, including improved fracture mechanics, rheological behavior, water absorption, and CO₂ absorbency. While the effects of TFs have been widely studied in low-strength concrete (20–25 MPa), mortars, and self-compacting concrete, their influence on high-strength concrete (C40/50) remains underexplored. Previous studies suggest that TFs could exhibit enhanced performance in high-strength concrete due to their strong bond with the binder. Addressing this gap, the present study evaluates the impact of TFs on concrete with compressive strengths of 40–45 MPa, using TF dosages of 0–60 kg/m³. The TFs were sourced from a local processing plant in Bratislava. The study evaluates various properties, including compressive strength (CS), modulus of elasticity (EM), tensile splitting strength (TSS), modulus of rupture (MoR), residual stresses, fracture energy, linear shrinkage (LS), water absorption (WA), and carbonation. Results show that concrete with a 60 kg/m³ dosage of TF exhibited notable improvements over plain concrete, with increases in CS (+3.8 %), TSS (+6.7 %), MoR (+4.1 %), and a reduction in linear shrinkage (−5.5 %). Additionally, fracture energy was significantly higher in all TFRC mixtures compared to plain concrete. Empirical models were developed to predict the linear shrinkage and carbonation of TFRC. The findings highlight the potential of TFRC to enhance the mechanical performance and sustainability of infrastructure, offering a competitive alternative to other metallic fibers.