Effect of Waste Tire Steel Fibers on Concrete Incorporating Palm Kernel Shell, Recycled Aggregate, and Coconut Shell

ABSTRACT The growing environmental impact of tire waste necessitates innovative recycling methods. With global tire production expected to reach 2.67 billion units by 2027, repurposing tire‐derived materials in concrete offers a sustainable solution. This study investigates the effects of steel fibers from waste tires on concrete incorporating coconut shells (CSs), palm kernel shells (PKSs), and recycled aggregates. The research examines how different fiber percentages influence fresh properties and strength. A concrete mix ratio of 1:2.19:2.46 (Cement: Fine Aggregate: Coarse Aggregate) was used, with an admixture at 1% by cement weight. Natural aggregates were replaced with recycled concrete aggregates (RCA), CSs, and PKS at 25%, 50%, 75%, and 100%, while steel fibers were added at 0.25%, 0.5%, 0.75%, and 1% by cement weight. Slump, split tensile, and compressive strength tests were conducted. Results showed that steel fibers enhanced cohesion but reduced slump due to increased stiffness. After 28 days of curing, the optimal mix contained 1% steel fibers and 25% aggregate replacements, achieving a balance between workability and strength. In addition, a life cycle and economic assessment indicated that these sustainable mixes can lower CO 2 emissions by 15%–25% and reduce costs by 2%–4%, confirming their potential for affordable, low‐carbon construction in Kwara state, Nigeria.