Behaviour of Cement-Stabilised Lateritic Soil: An Experimental Study

Lateritic soil, a residual soil found abundantly in tropical regions, is commonly used as a construction material. However, its natural fine-grained characteristics often fall below standard thresholds, necessitating soil stabilisation. In this study, a marginal residual soil stabilised with ordinary Portland cement was assessed via laboratory experiments in two stages. Initially, experiments, including unconfined compressive strength (UCS), field emission scanning electron microscopy (FESEM), X-ray diffraction, and energy-dispersive X-ray analysis (EDX), were conducted. The initial analysis showed that UCS increased with higher cement content and longer curing times. FESEM and EDX results revealed changes in the soil microstructure due to the formation of cementitious products and alterations in chemical compounds. In the second stage, unconsolidated undrained (UU) triaxial tests were conducted to evaluate the UU shear strength and durability of cement-stabilised soils. The UU triaxial test results indicated an increase in shear strength parameters (friction angle and cohesion) and peak deviator stress with higher cement content, attributed to the cluster formation of particles and hydration gels. Durability results showed that the strength variation and integrity of cement-stabilised soils depend on the cement percentage and the number of wetting–drying (W–D) cycles. Untreated specimens, as well as those with 3% cement, disintegrated (collapsed) after the first wetting phase. The UU deviator stress of 6% cement-stabilised soil decreased with increase in W–D cycles, while the UU deviator stress of 9% and 12% cement-stabilised specimens initially increased under certain W–D cycles and then decreased after further cycles.