Investigating the Effect of Cardamom Husks as a Partial Replacement of Cement in Mortar

The demand for concrete with superior performance and durability has grown significantly in recent decades. However, the Novelty of using high-quality, sustainable materials like cardamom husk powder has increased and encouraged building technology researchers to find new alternatives. In many cases, and potentially always, concrete requires the incorporation of at least one additional component, such as admixtures, supplementary cementitious materials, or fibers, to improve its strength and durability characteristics. The combined application of chemical and mineral admixtures empowers concrete specialists to design concrete formulations for diverse performance demands. The present investigation evaluated the compressive strength of mortar cubes containing varying levels of cardamom husk as a cement replacement (0%, 10%, 20%, and 30%). Cubes were cured in water for 90, 150, and 210 days after standard curing times of 7, 14, and 28 days to assess their suitability for subsequent corrosion rate testing. Mortar cubes containing 10% cardamom husk replacement exhibited the highest compressive strength at each curing age. However, compressive strength decreased across all mixtures with increasing cardamom husk content. Exposure of the samples to environments with different pH values (3, 5, 7, 9, and 11) and sodium chloride levels (5% and 10%) was carried out over the specified time intervals. A clear trend was observed where longer exposure durations resulted in higher compressive strength, indicating that extended water immersion positively influenced strength development. Among all tested pH environments, the neutral pH 7 yielded the maximum compressive strength and the minimum corrosion rate across all mortar specimens. In addition, elevating the salt concentration led to a decline in compressive strength and an acceleration in corrosion activity. The samples immersed in a pH 7 solution containing 5% sodium chloride for 28 and 90 days displayed the most favorable balance between increased compressive strength and reduced corrosion rate. The optimal cement formulation identified in this investigation comprised 90% wt. Cement and 10% wt. Cardamom husk.