Experimental investigation of rubberized concrete slab-on-grade containing tire-recycled steel fibers

The current study investigates the role of recycled steel fiber (RSF) and crumb rubber (CR) in the fracture behavior of rubberized reinforced concrete (RRC) slab-on-grade in terms of load-deflection responses, crack patterns, failure loads, deflection values, and toughness. RRC slab-on-grade measuring 1000 m x 1000 mm with a thickness of 60 mm were tested experimentally, and the soil was simulated with a steel model. The main parameters were the incorporation of CR as fine aggregate (i.e., 0%, 10%, and 20%) in the presence of RSF (0 and 0.5% by vol). The findings showed that a significant increase in the initial crack load of RRC slabs as compared to the reference slab, as well as slabs incorporated with high volumes of CR, showed favorable findings in post-cracking capacity and toughness compared to the reference slab. The incorporation of CR with 05% RSF can enhance the failure cracking load of concrete slabs by 12.79% (10%) and 20.97% (20%) at the center of the slab. The reference slab-on-grade failure load reached 43.0 kN, while the failure loads for the slabs containing 10% and 20% CR were 43.0 kN and 38.70 kN, respectively, without the addition of RSF. It was noticed that the slab deflection increased by 12.28% and 20.13%, respectively, compared to the reference slab. Finally, the slabs incorporating 0.5% RSF and 20% CR achieved a maximum failure load of 52.03 kN, which was attained because of additional microcracks forming closer to the loaded region, which enhanced the ductility of the slab-on-grade. Hence, the RSF and CR can be used to produce sustainable slab-on-grade with enhanced ductility, leading to a reduced overall cost and saving natural resources.