The durability of concrete in chemically aggressive environments, such as oil refinery wastewater systems, remains a critical challenge in infrastructure development. This study investigates the performance of concrete modified with binary agro-industrial pozzolans—corn cob ash (CCA) and coconut shell ash (CSA)—as partial replacements for ordinary Portland cement (OPC). Six concrete mixes were prepared with 0–30% combined SCMs by weight of binder. The specimens were exposed to 2% sulfuric acid (H?SO?) and 5% sodium sulfate (Na?SO?) for up to 90 days. Key parameters evaluated include compressive strength, mass loss, water absorption, sorptivity, density, and visual deterioration. The results revealed that the 15% replacement mix (M2) achieved optimal performance. It retained more than 94% of the control’s compressive strength at 90 days and recorded the lowest mass loss and permeability under both acid and sulfate attack. SCM addition contributed to secondary pozzolanic reactions, microstructural densification, and reduction in capillary porosity. Visual inspections corroborated quantitative findings, with M2 maintaining sound surface integrity, whereas higher SCM levels (?25%) showed signs of softening and erosion. Although density declined with higher SCM content, the values remained within acceptable structural thresholds. Overall, the findings affirm the suitability of CCA–CSA binary blends for enhancing concrete durability in aggressive industrial environments. The use of these locally sourced pozzolans also promotes sustainable construction and circular economy practices, making the approach particularly beneficial for developing regions and petrochemical infrastructure.
Umar et al. (Tue,) studied this question.