Optimizing the properties of seashell ash powder based concrete using Response Surface Methodology

Abstract

Cement serves as a crucial binder in concrete production. Cement consumption is projected to reach around 4.4 billion tons in 2020, up from approximately 1.6 billion tons in 2000. By 2050, it is expected to increase by 13 to 23%. The environmental impact of cement production is significant, as producing one ton of cement emits roughly 0.73 to 0.99 tons of carbon dioxide. The cement industry is responsible for about 7–8% of global CO₂ emissions and accounts for 26% of the world’s total CO₂ emissions. This study explores the feasibility of using seashell ash powder (composed mainly of calcium carbonate) as a partial cement replacement in concrete production. This study highlights the potential of seashell ash powder as a sustainable supplementary cementitious material, improving concrete workability and strength properties (Compression, flexural and split tensile) while promoting environmental sustainability through waste utilization. This study analyses the gap using Response Surface Methodology to optimize seashell ash powder ranging from 2 to 10% with different water-cement ratios ranging from 0.4 to 0.6. Results showed that higher seashell ash powder levels, combined with lower water-cement ratios, significantly enhanced compressive strength and workability. Optimal mix designs were identified, with the best composition featuring 10.94% seashell ash powder and a 0.52 water-cement ratio, achieving a desirability score of 68.81%.