Reducing the extraction of natural resources is crucial for a more sustainable world, especially in construction and infrastructure projects that consume large amounts of materials. Eggshells are a waste product produced in enormous quantities around the world. Recycling or reusing this waste instead of disposing of it in landfills can be a valuable opportunity in the context of a circular economy. Eggshells are rich in calcium carbonate and can potentially replace limestone in lime production [1]. Studies show that eggshell limes have less impact on aquatic ecotoxicity, terrestrial ecotoxicity and land occupation compared to traditional limes because two processes (Quarrying of limestone and Limestone improvement) are eliminated [2]. This study aimed to compare the strength enhancement of eggshell lime with a commercially available lime in a clayey soil for various lime percentages. It also examined the impact of porosity on the strength of the treated soil. The ICL (Initial Consumption of Lime) Method was used to determine the optimal lime content, with three percentages (3, 5 and 7%) for both limes being tested for Unconfined Compressive Strength (UCS) at three different densities and a curing time of 28 days. Additionally, a physical–chemical and mineralogical characterization of both eggshell and commercial limes was carried out using laser granulometry and X-Ray diffraction analysis (XRD). The study found that eggshell limes demonstrated better physical–chemical-mineralogical qualities for soil stabilization applications than commercial lime. Both limes were assessed for their strengths at different quantities and densities, and the study revealed that eggshell lime outperformed the commercial lime.