Development and characterization of blended cements containing seashell powder

This study evaluates potentiality of waste seashell to be used as additives in production of blended cement. Cements with binary blends of ordinary Portland cement (OPC) and seashell powder (up to 30% by mass) as well as ternary blends of OPC, seashell powder (up to 7% by mass) and natural pozzolan (up to 30% by mass) were developed and their characteristics were investigated in terms of density, fineness, specific surface, chemical composition, and setting time. Properties including compressive strength, flexural strength, and water demand were determined for mortars made of the developed cements. All the properties characterized for the blended cements were compared with those of the OPC as well. Setting time of all the blended cements was higher than that of the OPC, which is beneficial for construction in hot climate. All the blended cements containing seashell powder, presented compressive strength relatively close to that of the OPC at all three ages of 3, 7, and 28 days, demonstrating competitiveness of the produced blended cements with OPC. Results indicate that seashell powder can be used as cement replacement in developing blended cements not only to enhance sustainability and reduce costs of production, but also to promote the properties and performance of concrete.