Engineered Water Repellency for Mitigating Swell Behavior in Expansive Foundation Soils

Expansive soils, characterized by large deformations due to clay mineral swelling, pose persistent challenges for geotechnical and foundation engineers. These movements can continue for years, raising concerns for project owners. Moisture control is vital, as moisture triggers swelling and shrinkage in these soils. To address this issue, engineered water repellency (EWR) is proposed as an innovative solution. EWR involves making soils hydrophobic using organosilanes (OS), which keeps the soil at a stable moisture content year-round. In this study, a highly expansive clay was treated with OS at a 1:10 ratio (OS:soil by weight). The treatment significantly reduced expansive properties (soil plasticity and swelling), and a 75% increase in unconfined compressive strength after seven days. This approach offers a promising alternative for mitigating expansive soil issues, providing engineers and designers with an effective tool to address this challenging geotechnical problem.