Scientists who tested eggshells as cement substitute found an unexpected result: Adding 10% processed eggshell powder made mortar stronger, but increasing it further had opposite effect

Researchers have found a potential use for discarded eggshells by processing them into powder and using it as a partial replacement for cement in mortar. In laboratory tests, mortar containing 10% eggshell powder recorded higher compressive strength after 28 days than conventional mortar. The findings suggest that eggshell powder could help reduce cement use, although further research is needed to assess its long-term durability and suitability for large-scale construction.