Recycled Hybrid Fiber Reinforced Concrete Modified with Nano Zirconia: Mechanical Performance and Pavement Application

Conventional plain concrete has a relatively low post cracking flexural resistance and therefore required larger pavement thickness. Hybrid fiber reinforced concrete using Recycled Tire Steel Fiber (RTSF) and Recycled Nylon Fiber (RNF) modified with Nano-ZrO₂ is evaluated in terms of its mechanical, structural and sustainability performance for overcoming such limitations and decreasing the amount of natural materials used in production of concrete. To improve the multi-scale crack-bridging capabilities, a number hybrid combinations were made by utilizing 1.5% total fibre volume and Nano-ZrO₂ 0.2% of weight of cement. All mixture's mechanical properties were assessed and utilized as input parameters for pavement thickness design in Street Pave software. The results showed that hybrid mixes' mechanical performance significantly improved in all areas, with compressive strength rising to around 127% and tensile strength in RTSF-rich blends reaching up to almost 200%. Flexural and residual flexural capabilities also dramatically boosted, especially in the hybrid RTSF1% + RNF0.5% combination that demonstrated the highest synergy in stiffness, ductility and post-crack load retention. Pavement slab thickness might be lowered by as much as 25–26% due to these strength benefits, which directly translated into enhanced structural efficiency. The cost analysis of basic concrete constituent materials showed that through optimization of thickness of slabs, about 25 percent of the cost of the material per unit pavement area could be reduced.