Recycling eggshell waste for sustainable soil stabilization: Properties, performance and future potential

In recent times, the growing demand for sustainable construction practices has led to the exploration for innovative solutions to reduce dependency on natural resources and utilize waste materials. Limestone, a primary raw material in civil engineering, is extensively used for construction, but its extraction and processing significantly contribute to environmental degradation. In this context, eggshell waste, a rich source of calcium carbonate, emerges as a valuable alternative. This study examines the potential of limes derived from chicken eggshells as binders for soil stabilization. The physical, mineralogical, and chemical properties of the produced quicklime and hydrated lime are extensively characterized. Further, a comparative analysis is performed between hydrated lime derived from eggshells and commercial hydrated lime (CHL). The findings indicate that both eggshell quicklime (EQL) and eggshell hydrated lime (EHL) meet ASTM standards, making them suitable for sustainable soil stabilization applications. Moreover, the mechanical performance of EHL was investigated and compared with CHL at incremental dosages of 3 %, 5 %, 7 %, and 9 %, by adding sugarcane bagasse ash. The results from the study indicated that a 7 % lime dosage yielded the most significant improvements in unconfined compressive strength (UCS), California bearing ratio (CBR), cohesion, and internal friction angle for both lime types. Remarkably, the EHL outperformed CHL, exhibiting enhanced performance in terms of UCS (2819.23 kPa), CBR (33.86 %), cohesion (552.85 kPa), and angle of internal friction (49.24°). These findings highlight the prospect of lime derived from eggshell waste as an effective solution for soil stabilization, offering a sustainable approach to addressing geotechnical challenges.