A Mixture Design of Concrete Hollow Blocks with Combined Rice Husk Ash, Eggshells Ash and Coconut Shell as Partial Replacement for Cement and Fine Aggregate.

Concrete Hollow Blocks (CHB) serves as essential building materials in constructions due to their versatility and structural integrity. This study explored the potential enhancement of CHB properties through the incorporation of alternative materials, namely Rice Husk Ash (RHA), Eggshell Powder (ESP), and Coconut Shell (CS). The research investigated the effects of varying proportion of these materials on the compressive strength, moisture content, and density of CHB. Series of laboratory experiments were conducted in the fabrication of CHB prototypes with different mix proportions, in accordance with ASTM Specifications. Compressive strength tests were performed on specimens cured over 7,14, and 28-day periods to assess their performance compared to traditional CHB formulations. Preliminary findings indicated that incorporating RHA, ESP, and CS lead to the improvements in compressive strength and durability of CHB. However the increase in total replacement materials lead to deceased in compressive strength particularly evident in specific mixtures T3 and T4. Notably, Design Mixture (T2), containing 4% RHA, 6% ESP, and 5% CS, exhibited greater performance in terms of compressive strength compared to conventional mixtures T3 and T4. Notably, Design Mixture (T2), containing 4% RHA, 6% ESP, and 5% CS, exhibited greater performance in terms of compressive strength compared to conventional mixtures. Design Mixture (T2). is the recommended mixture that showed highest performance among other mixtures.