Optimization of Waste Casting Sand in Cement Brick Manufacturing: A Comparative Analysis of Compressive Strength and Washout Percentage.

Abstract

This research studies the possibility of recycling Waste Casting Sand (WCS) as a substitute for natural sand in cement brick manufacturing. WCS is a major byproduct of metal casting that loses its usefulness with time. As environmental and economic benefits due to WCS usage, enabling a reduction in the dependency on natural sand, minimization of waste disposal problems, and promotion of sustainable construction. Four brick methods (WCS proportions 0%, 60%, 80%, and 100%) were studied. Method 1 is a control mix with no WCS (conventional cement brick), Method 2 is 60% WCS and 40% natural sand, Method 3 is 80% WCS and 20% natural sand, and Method 4 is 100% WCS. A common mix proportion that is used in cement brick manufacture is mostly 1 cement (14%), 2 sand (29%), 4 chip stone (57%), and as required water. Compressive strength (N/mm²) and washout percentage (4 bricks each from one method), which are key indicators of the durability of bricks, were evaluated as major parameters. Results showed that 60% WCS bricks (Method 2) gave the greatest compressive strength (6.31 N/mm²), with better performance compared to the conventional brick (3.11 N/mm²). Method 3 (80% WCS) and Method 4 (100% WCS) gave 5.17 N/mm² and 4.94 N/mm², respectively. Increased WCS content, however, increased the percentages of washout, with Method 4 being at 0.029% (± 0.007) while Methods 1, 2, and 3 gave 0.008% (± 0.001), 0.007% (± 0.001), and 0.009% (± 0.004), respectively (ANOVA test). Particularly at 60%, enhances compressive strength with acceptable durability. Methods 3 and 4 also exhibited better strength than conventional bricks, and all three methods had an insignificant environmental impact due to the percentage of washout. The findings suggest a range of sustainable production of bricks using WCS replacement of 60% - 100% and provide a sustainable solution for reducing industrial waste while conserving natural resources in brick manufacturing.