Experimental investigations on sustainable mortar containing recycled seashell powder as cement partial replacement

Abstract Creating sustainable mortar containing recycled seashells is an innovative approach that can contribute to environmental conservation and reduce waste. The use of seashells as a partial replacement for traditional raw materials in mortar can have several benefits, including conservation of natural resources, waste reduction, and improved material properties. The current study uses Marsh Clam seashells after crushing the cleaned seashells into powder. Heated ( up to 600C°) and unheated seashells were considered in the experimental investigation. In both batches, a seashell powder (heated and unheated) was replaced with OPC cement in proportions of 6, 9 and 12% in the mixing process. XRD, SEM, EDS and mechanical tests were employed to determine the crystal structure and to provide a comprehensive understanding of the physical, chemical, and structural characteristics of the substance. The study concluded that the calcium carbonate (CaCO3) that is nature chemical form of seashells was turned to calcium oxide (CaO) during the heating process and the resulted product was highly reactive with water, improved microstructural properties of the concrete. It also promotes better particle packing, reduce porosity, and create a denser, more uniform concrete matrix and enhancing the overall performance of the material.