Initial Water Content and Total Suction Effect on the Swelling Behavior of Lime-Stabilized Expansive Soil

Abstract Swelling soils pose significant geotechnical challenges due to their volumetric instability during seasonal variations in water content, which can cause damage to overlying structures. Lime stabilization is widely employed to mitigate this; however, a rationalized dosage for lime is still required. The initial unsaturated condition of swelling soils tends to govern their expansive properties, with the initial water content ( w i ) dictating the initial hydration of clay minerals and the initial suction influencing the soil’s water adsorption affinity. Although the adjusted porosity/volumetric lime content index ( η / L i v ) has proven effective for describing swelling properties, a knowledge gap persists regarding the influence of w i on this dosage. Thus, this study investigates the influence of initial w i and total suction on the swelling behavior of a lime-stabilized soil. A series of vertical swell, swelling pressure, and total suction tests were performed on samples compacted at dry unit weights of 13.5, 14.5, 15.5, and 16.5 kN / m 3 , hydrated lime contents of 2%, 3%, and 4%, initial water contents of 16%, 19.5%, and 23%, following a full factorial design approach. The results showed that increasing the initial water content reduces the magnitude of soil swelling. Lower values of initial suction ( < 5,500 kPa ) have a significant effect on swelling properties; beyond this threshold, the effect becomes less pronounced. The application of the η / ( L i v ) α index revealed a separate dosage curve for each w i value. The normalization of these curves yields a relationship between swelling pressure ( P S ) and vertical swelling ( ε S ), enabling the prediction of P S based on ε S and vice versa, thereby minimizing laboratory labor. These observations were corroborated by an analysis of variance (ANOVA) and scanning electron microscopy analyses. In summary, this work presents a rational and practical framework for assessing the influence of w i and total suction on swelling properties of soils stabilized with hydrated lime.