Mechanical Behaviour and Sound Intensity Characteristics of Compressed Earth Blocks Reinforced with Powdered Pozzolan and Cocoa Pod Husk Ash

The construction industry in developing countries increasingly seeks sustainable, low-cost, and acoustically efficient building materials. Compressed Earth Blocks (CEBs) are widely recognized as an environmentally friendly alternative; however, their limited mechanical strength and poor sound insulation restrict broader adoption. This study explores the potential of enhancing CEB performance through natural stabilizers that is powdered pozzolan and cocoa pod husk ash (CPHA). The research aimed to address two critical questions: (i) how the combined use of these additives influences the mechanical behaviour of CEBs, and (ii) whether they can improve acoustic insulation properties. Experimental CEB samples were prepared with varying proportions of pozzolan (0-20%) and CPHA (0-10%). Mechanical tests, including compressive and flexural strength, were conducted, alongside assessments of acoustic performance. The results demonstrated that incorporating 10% pozzolan with 10% CPHA significantly enhanced compressive strength and ductility, achieving 0.215 MPa compared to 0.121 MPa for the control. Flexural strength improved markedly in blocks containing 20% pozzolan and 10% CPHA, reaching 0.156 MPa, more than double the control value. Acoustic evaluation revealed that blocks with 5% pozzolan and 10% CPHA reduced sound transmission by over 16 dB relative to the control, highlighting their potential in improving indoor comfort. Overall, the findings confirm that the synergistic use of pozzolan and CPHA not only mitigates the mechanical shortcomings of traditional CEBs but also provides significant acoustic benefits. This study contributes to the knowledge base on sustainable construction materials and demonstrates a practical pathway for developing eco-friendly, affordable, and higher-performing housing solutions in resource-constrained contexts.