Influence of Drying and Wetting Cycles on SWCCs of Fine-Grained Soils

The soil-water characteristics curve (SWCC) is greatly influenced by the path that is followed for suction measurement (i.e., drying or wetting path) and the number of cycles of these paths to which the soil is exposed. To evaluate the influence of these parameters, drying- and wetting-path SWCCs of three fine-grained soils were developed for single and multiple cycles by employing the Aquasorp (R) Isotherm generator. This device has been primarily employed for food products, powders, and amorphous materials for determination of their moisture sorption isotherm, which relates moisture content to water activity. As water activity can be mathematically related to soil suction, the Aquasorp (R) can be used for developing the SWCC. Hence, demonstrating the potential of the Aquasorp (R) for characterizing fine-grained soils becomes essential. The present study has been focused at highlighting the possible uncertainties associated with establishment of the SWCCs (both during drying and wetting paths) and the benefits and limitations of the Aquasorp (R) in achieving these objectives. Furthermore, by employing mercury intrusion porosimetry (MIP), the significance of capillarity on soil suction, which in turn governs the SWCC, has been demonstrated.