Sustainable Soil Stabilization Using Eggshell-Derived Lime: A Comparative Assessment Against Commercial Lime

The sustainable use of resources in construction requires alternatives that reduce the extraction of natural raw materials and promote circular-economy practices. Eggshell waste, rich in calcium carbonate, can serve as a renewable precursor for lime production, while fly ash offers pozzolanic activity for soil improvement. This study compares the performance of eggshell-derived lime and commercial lime in stabilizing a clayey soil, incorporating different lime contents (3%, 5%, and 7%) and fly ash percentages (0, 12.5, and 25%). Initial Consumption of Lime (ICL) tests guided mixture design, followed by Unconfined Compressive Strength (UCS) tests performed at various densities after 28 days of curing. Mineralogical and chemical analyses were conducted through laser granulometry and X-ray diffraction. Results indicate that all mixtures enhanced soil strength, with eggshell lime showing superior mechanical performance under identical experimental conditions, supported by qualitative microstructural observations. The findings demonstrate the potential of eggshell-derived lime as a sustainable substitute for conventional lime, reducing environmental impacts while supporting resource-efficient soil stabilization strategies.