Dual waste valorization in concrete: a performance-based study on waste foundry sand and bottom ash materials

ABSTRACT The rising global demand for sustainable construction materials has catalyzed the exploration of industrial byproducts in concrete production, aiming to reduce environmental impact while maintaining structural integrity. Among these byproducts, WFS and BA are two prominent solid waste streams generated from the metal casting and thermal power sectors, respectively. Their potential as partial replacements for natural fine aggregates in concrete has gained increasing attention due to their availability and environmental benefits. This study evaluates the mechanical and durability performance of concrete with WFS and BA, both as standalone and binary combinations. A total of eleven distinct mix designs were prepared and tested, with replacement levels ranging from 0% to 40%. The optimum blend, consisting of 20% WFS and 20% BA, exhibited significant performance enhancements compared to the control mix. Improvements included a 7.8% increase in 28-day compressive strength, a 7.5% rise in split tensile strength, and a 7.7% boost in flexural strength. Durability parameters also improved notably, with an 18.2% reduction in chloride ion permeability, a 14.5% decrease in drying shrinkage, and an 11.2% limitation in acid-induced strength loss. These findings highlight the synergistic effects of WFS and BA in improving concrete quality, to sustainable waste valorization in construction materials.