Abstract
The freezing of water in soil induces heaving, altering its structure, strength, and stiffness, which compromises pavement integrity. Midwestern U.S., where frost depth reaches 91 cm, heaving can exceed 64 cm, and subsequent thawing destabilizes the soil, increasing pavement failures and maintenance costs. Diverse measures are utilized to reduce the impact of frost heave and thaw settlement, including structural adaptations and neutralization methods, such as insulating pavements and modifying soil. Engineered water repellency can significantly limit water movement, a key factor in frost action, preventing ice segregation. This study evaluates Organosilanes (OSs), silica-based coupling agents that imparts hydrophobicity in soil, for reducing frost heave in highly frost-susceptible subgrade soils. Four distinct subgrade soils with high susceptibility to frost were treated with two different concentrations of OSs and underwent tests to measure frost heave and thaw weakening. The freeze-thaw performance of untreated and treated soils was assessed based on maximum heave, heave rate, moisture distribution, and water intake. The application of the OS-treated soil results in a reduction of the maximum soil heave by up to 96 % and 90 % using OS1 and OS2, respectively. The effectiveness of heave mitigation typically improves as the concentration of the chemical increases. Post-test moisture content in treated soils was significantly lower than in untreated soils, with water migration reduced by up to 97 %. By incorporating water repellency into pavement soils, it is possible to avoid freeze-thaw damage, maintain consistent moisture levels, enhance performance, minimize design uncertainties, reduce expenses related to materials and construction, and decrease emissions.