Sustainable use of seashells as binder in concrete production: Prospect and challenges

Cement production has a lot of adverse effects on the environment and the globe at large. With all these negativities, it becomes imperative to find alternative materials that are sustainable and environmentally friendly to reduce some of these adverse effects. Seashells are one of the numerous wastes that are quickly accumulating onshore coasts. Using seashells in cement aids in ridding seashells from seashores and landfills, and transforming these wastes to viable cementitious materials. This review paper summarizes past studies on using seashell ash powder as a partial replacement for cement in several proportions. The workability of concrete reduces with the addition of seashell ash. It also indicates a reduction in compressive strength of concrete whose cement content is partially replaced with seashells as compared to those of ordinary Portland cement (OPC). Also, at low percentages of 5%–15% ranges, the concrete absorption and porosity are less compared to standard. Though, with greater replacement levels of up to 25%–50%, these values are enhanced. The workability of concrete is reduced with the addition of higher percentage of seashell ash. After long curing periods, concrete permeability is also reduced, and the mechanical performance is enhanced