The demand for sustainable and environmentally friendly soil stabilization methods for subgrade improvement for pavements has led to exploring techniques that minimize ecological impact while optimizing engineering properties. Traditional stabilizers like cement and lime, though effective, have significant environmental drawbacks, including a high carbon footprint, disruption of vegetation, and health risks to workers. This study investigates the efficiency of biopolymers and eggshell powder as eco-friendly, sustainable soil stabilization agents. Parameters such as compaction characteristics, California Bearing Ratio (CBR), and micro-structural analysis were assessed. The research evaluates soil samples treated with varying concentrations of biopolymer (1%, 2%, and 3%) and eggshell powder (4%, 6%, and 8%). Results indicated that biopolymer addition slightly decreased the maximum dry density (MDD) and increased the optimum moisture content (OMC), while eggshell powder slightly increased MDD and decreased OMC. The optimal mix, soil + 1% xantham gum + 6% eggshell powder, enhanced CBR by 225.6% and 323.8% for soaked and unsoaked conditions, respectively. The scanning electron microscope revealed that treated soil samples transformed into a hard solid matrix, demonstrating improved stability. EDX analysis revealed the mineralogical composition of the mixes. Overall, the use of biopolymers and eggshell powder not only enhances soil strength but also promotes environmental sustainability.
Kalita et al. (Wed,) studied this question.