Infiltration characteristics of chemically-treated water-repellent kaolin

Degree of water repellency significantly influences the infiltration behavior of water-repellent soils. In this study, the chemically treated water-repellent kaolin clays with different concentrations (C_O) of an organosilane solution are examined to explore the effect of water repellency on its infiltration characteristics. Experimental results show that the soil-water contact angle tends to increase with increasing C_O until C_O = 5%, and then shows an almost constant value with increasing C_O. The water infiltration time (WIT) results show that water infiltration resistance is significantly improved by organosilane treatment (CO ≥ 5%) under low hydrostatic pressure (WP). However, as the hydrostatic pressure increases, WIT is converged (C_O = 5%) or exacerbated (C_O = 10% and 20%) to the WIT of untreated clay. The different behaviors of infiltration are discussed in terms of wetting patterns. The findings can be used to improve a conventional hydraulic barrier system.