Fire performance of PET-based composite wall cladding reinforced with recycled steel fibers and rice husk ash

Abstract This research develops a sustainable and cost-effective composite cladding engineered from recycled polyethylene terephthalate (PET), reinforced with recycled tire steel fibers (RSFs), river sand, and rice husk ash (RHA). Highlighting the potential need for fire-resilient building materials, this study valorizes non-biodegradable waste to provide a high-performance alternative to traditional cladding. Specimens were produced via hot-mixing with a fixed concentration of 2.5% RSFs and 50% PET; RHA-replaced sand at fractions from 0% to 20% (maintaining a 1:1 PET-to-sand ratio in the control mix) to optimize performance. Physical and mechanical evaluations demonstrated an inverse relationship between density and RHA content, with density decreasing from 2.5 g/cm³ (0% RHA) to 1.5 g/cm³ (20% RHA). Water absorption increased proportionally from 1.8% to 3.4% with higher ash content, remaining within acceptable limits. Compressive strength peaked at 12.2% RHA, reaching 27.4 MPa, surpassing the 22.6 MPa control sample, thanks to the crack-arresting action of RSFs. Fire testing confirmed structural integrity up to 150 °C, with melting observed at 300 °C, confirming suitability for standard external environments. An economic analysis establishes that the optimal composite formulation-comprising 48.7% PET, 2.5% RSFs, 12.2% RHA, and 36.6% river sand, yields a standard panel (2.44 m x 1.22 m x 0.02 m, weighing 112.52 kg) with a raw material production cost of approximately USD 7.71 per m² (about USD 22.94 per panel, including a 10% contingency). This offers significant economic savings compared to traditional granite and ceramic cladding, presenting a durable, high-performance solution for sustainable construction.