Effect of addition of eggshell powder to improve the compressibility parameters of Doukane’s clay soils: a case study Tebessa-Algeria

This study examines the effects of Eggshell Powder (ESP) as an additive material, used in varying amounts from 2% to 8%. It focuses on how ESP influences the physical properties of expansive clay soils, particularly concerning compressibility parameters, the oedometer modulus (E′), and swelling pressure. Additionally, the study investigates how ESP affects the behavior of clayey soil subjected to consolidation and swelling tests. It observed that the investigated soil compressibility index had a high value and decreased with the addition of ESP, evidencing further that soil is highly compressive. It found that a decrease in the compressibility index with an increased ESP increases the mechanical stability of the soil by reducing the capacity for compressive strain. The high swelling index with the addition of ESP shows a tendency toward possible swelling when contacting water. The initial addition of ESP increases the susceptibility of the soil to expansion, and the volumetric compressibility coefficient, mv, decreases. The addition of ESP increases the oedometric modulus E′ from 359 kN/m² to 1166 kN/m². The ESP has drastically enhanced the swelling characteristics of soil, having swelling pressures of 720 kN/m² at 0%, 750 kN/m² at 2%, 760 kN/m² at 5%, and 780 kN/m² at 8%.