Utilization of Industrial Waste Fillers for Performance Enhancement of Basalt Fiber Reinforced Epoxy Composites

ABSTRACT The growing demand for sustainable composite materials has motivated the incorporation of industrial waste fillers into polymer systems. In this study, NaOH‐treated basalt fiber reinforced epoxy composites were fabricated using hand lay‐up followed by autoclave curing to enhance fiber–matrix adhesion and minimize void content. Four hybrid‐filler formulations were developed with a constant 40 wt. % basalt fiber and 12 wt. % total filler, varying the proportions of fly ash (FA) and marble dust (MD). Comprehensive characterization, including void content, water absorption, hardness, tensile, compression, flexural, and impact testing, was conducted, and fracture mechanisms were examined using SEM. The composite containing 8 wt.% FA + 4 wt.% MD exhibited the most favorable performance due to the synergistic packing effect of dual fillers and improved interfacial bonding from NaOH‐treated fibers. This formulation showed enhancements of 18% in tensile strength, 13% in compressive strength, 19% in flexural strength, and 18% in impact strength compared to single‐filler systems. The findings demonstrate that combining NaOH‐treated fibers with hybrid industrial waste fillers yields a high‐performance and environmentally sustainable composite system.