Chemically Induced Water Repellency and the Freeze–Thaw Durability of Soils

Abstract

Organosilane (OS) is a silicon-based coupling agent capable of producing hydrophobicity in soils. This study evaluated the applicability of OS in reducing the freeze–thaw impacts on subgrade soils. A frost-susceptible soil was treated with two different dosages (50% and 100% by weight) of 10% OS solution. The OS-treated soils were dried and incorporated into natural soil as layers of 2.5 and 5 cm thickness. The freeze–thaw performances of natural and OS-incorporated soils were then evaluated in terms of maximum frost heave, heave rate, soil moisture distribution, and temperature profile. The OS-treated soil layers decreased frost heaving by 48%–74%. The heave rate of untreated soil was 13.8 cm/day, which was decreased to 4 mm/day with an incorporation of 5 cm-thick layer of 50% OS-treated soil. A 5 cm–50% OS-treated layer was found to be more efficient compared to a 5 cm–100% OS-treated layer in improving the freeze–thaw performance of the soils.