Investigation of banana fiber-reinforced diatomaceous earth slurry treatment of recycled aggregate for structural concrete applications

Abstract

This study proposes a sustainable method for improving the performance of RAC through the surface treatment of RCA using a DE and BF reinforced slurry. RCA was treated with a mix containing 5% DE, ordinary Portland cement, and banana fiber ranging from 0–7% to improve its physical and mechanical properties. The optimal mix, containing 5% fiber (5/5-RAC), significantly enhanced aggregate quality by increasing specific gravity and reducing crushing, impact, and abrasion values. Concrete made with treated RCA showed notable mechanical improvements, with compressive strength increased by 25.14%, tensile strength increased by 36.58%, and flexural strength increased by 72% compared to untreated RAC. Durability was also enhanced, evidenced by reduced water absorption, lower porosity, and less mass loss after exposure to elevated temperatures (200°C–800°C). Microstructural analysis (SEM and XRD) confirmed better bonding, fiber bridging, and C–S–H formation, contributing to long-term stability. From a structural application, the 5/5-RAC mix exhibited significant improvements in shear performance. Beams without stirrups showed a 16.12% strength increase at 1.6% reinforcement and 22.22% at 2.5%, while a 13.33% improvement was also noted in beams with stirrups. These findings highlight the method’s effectiveness for practical structural use. Overall, this treatment method offers a cost-effective, eco-friendly, and practical applicable to enhance the quality and durability of RAC, supporting sustainable construction practices.