<p>Soft clays are problematic materials that are normally not suitable for construction applications. Soil stabilization with conventional stabilizers has been widely utilized as a solution to this problem. Nevertheless, these conventional materials are non-renewable and of energy-intensive production. Thus, alternative materials are growing in demand. The main goal of this work was to study the stabilization of kaolin–bentonite blends through the application of an alternative quicklime (produced from eggshell waste) as the stabilizing agent at elevated moisture contents. For that extent, unconfined compressive strength, split tensile strength and initial shear modulus tests were executed. In addition, a rational dosage methodology (porosity/lime content index) was also applied for the stabilized mixtures. Results have shown that the mechanical behavior of the cement blends was governed by kaolin/bentonite ratio, lime content and dry unit weight. The increase in kaolin/bentonite ratio hindered strength and stiffness, while an increase in lime content and dry unit weight improved the mechanical behavior. Additionally, the porosity/lime content index was shown to be a viable dosage method to predict the strength and stiffness of cemented kaolin–bentonite blends. Finally, a statistical analysis of variance corroborated the experimentally observed findings.</p>