Technical and environmental performance of eggshell lime for soil stabilization

Abstract

Abstract Searching for alternative materials to reduce the extraction of natural resources is key to a more sustainable world and relevant to construction and infrastructure projects in which large amounts of materials are used. Eggshell is a solid waste that is rich in calcium carbonate and can potentially replace limestone for lime production. This research examines the environmental impacts of eggshell limes and commercially available limes using Life Cycle Assessment (LCA). In addition, a physical–chemical and mineralogical characterization of eggshell limes and an assessment of the strength and stiffness of a sandy soil stabilized with ground glass and such limes are carried out. Results show that eggshell limes have reduced impacts for aquatic ecotoxicity, terrestrial ecotoxicity and land occupation when compared to traditional limes as two processes (Quarrying of limestone and Limestone improvement) are eliminated. A reduction of 65.1% in damage to Ecosystem quality was observed for eggshell quicklime (versus quicklime from limestone) and of 50% for eggshell hydrated lime (versus hydrated lime from limestone). Eggshell limes were found to have adequate physical–chemical-mineralogical characteristics for soil stabilization applications, being composed by 97.0% calcium oxide and 2.0% magnesium oxide (quicklime) and by 89.6% calcium hydroxide, 2.9% magnesium hydroxide and 5% calcium carbonate (hydrated lime). Lastly, both limes improved the strength and stiffness of the studied soil by reacting with ground glass (pozzolan).