Engineering Performance and Sustainability Assessment of Concrete Incorporating Banana Leaf Ash and Rice Husk Ash

The environmental effects of cement manufacturing and river sand removal have increased interest in environmentally friendly construction materials that reduce resource use and greenhouse gas emissions. This study examined concrete using banana leaf ash (BLA) as a partial replacement for Portland cement and RHA to replace fine aggregate in concrete proportioned for an M30 target strength. Five mixes containing 0–20% each of BLA and RHA were evaluated for fresh properties, mechanical characteristics, durability, economic feasibility, and sustainability characteristics. The best-performing mix (M2) contained 10% BLA and 10% RHA and achieved the greatest 28 day compressive strength of 39.2 MPa, exceeding the control at 34.8 MPa. One-way ANOVA confirmed statistically significant differences among compressive strength values; Tukey HSD post-hoc analysis identified statistically significant differences in seven of the ten pairwise comparisons. M2 also showed higher split tensile and flexural strength and lower water absorption and sorptivity than the control. Cost comparison indicated minimal material cost savings due to substituting RHA for river sand. Sustainability analysis showed reduced cement, river sand, and embodied CO2 from cement manufacturing. These data indicate retained engineering performance overall.