Water migration in unsaturated partially hydrophobic soils

This paper presents new insights into the effects of hydrophobic particles on water migration in fine-grained soils. The experimental set-up for this study uses columns of soil instrumented with sensors to measure the water content of soil during capillary rise, infiltration under imposed pressure and drainage. The soil was mixed with microparticles of Teflon (Polytetrafluoroethylene (PTFE)). The water retention curve was measured for mixtures with three different percentages of hydrophobic particles: 0, 2 and 5% by weight. Moreover, the water repulsion curve of the PTFE particles was measured using the water intrusion test. The results of this study show a significant effect of hydrophobic particles on capillary rise, but water repellency decreases when imposing a pressure. This study provides a new survey that could be useful for understanding the benefits and limitations of soil hydrophobisation.