Analytical Study of Angular Fly Ash Aggregates in Lightweight Concrete: Strength Development Properties

This study investigates the performance of angular fly ash aggregates (AFAA) as a sustainable alternative to conventional coarse aggregates in lightweight concrete applications. Experimental analysis evaluated various proportions of AFAA (0%, 25%, 50%, 75%, and 100%) as replacements for natural aggregates, with compressive strength measurements conducted at 7, 14, 21, and 28 days of curing. Results demonstrate that concrete containing up to 50% AFAA achieved satisfactory compressive strength development, with the optimal blend (50% natural aggregate and 50% AFAA) reaching acceptable target strength at 28 days. A regression-based mathematical model was developed to predict compressive strength evolution over time, showing high correlation (R² values between 0.914-0.992) across all mixture proportions. Comparative analysis with existing strength prediction models confirms the reliability of the proposed equations. Beyond mechanical performance, AFAA incorporation offers significant environmental benefits by reducing natural resource extraction impacts including habitat destruction, deforestation, soil erosion, and water contamination. The findings suggest that appropriately proportioned AFAA can serve as a viable alternative in lightweight concrete production, aligning with sustainable construction practices while maintaining adequate structural performance.