Seashell Powder as a Sustainable Alternative in Cement-Based Materials: A Systematic Literature Review

Seashells have been explored as a partial replacement for cement in cementitious matrices to promote sustainable waste management and decrease the carbon footprint associated with cement production. As research in this area expands, it is essential to synthesize current findings and practices to guide future studies on the feasibility of using seashells as a filler. This study analyzed existing research on using seashells as a partial cement replacement in cementitious composites through a systematic literature review conducted across six scientific databases, yielding 44 studies for data analysis and synthesis. Key findings identified the shell processing methods, established typical ranges for shell powder’s physical–chemical properties and dosage, and quantified the impact on mechanical properties in binary mixtures. The reported effects on mechanical properties varied among studies, potentially due to differences in processing techniques and the origins of the shells. Most improvements in composite properties were observed with 5% to 15% cement replacement in binary mixtures. Overall, incorporating shell powder reduces the carbon emissions of the produced composites. Further detailed investigations into shell processing variables and dosages are recommended to better understand how these factors influence the properties of the composites produced.