Thermal and electrical conduction in unsaturated sand controlled by surface wettability

• DOI: 10.1007/s11440-014-0317-0
• Publication Date: 2014-04-30T07:52:25Z
• Authors: Yi Dong; Sibel Pamukcu
• Keywords: 0401 agriculture, forestry, and fisheries; 04 agricultural and veterinary sciences; 6. Clean water

Water repellency has significant implications on the thermal and electrical conduction properties of unsaturated soils, but less understood. This study presents the results of a laboratory study that show the evolution of thermal and electrical conductivity of unsaturated hydrophilic and hydrophobic soils with degree of water saturation using surface synthesized soils. Sand particles were chemically grafted with a thermal-sensitive polymer to make their surfaces hydrophobic at a critical elevated temperature. A transient line source heating method and two-terminal electrode system were used to obtain the thermal and electrical conductivities of the hydrophilic and hydrophobic specimens. A controlled drying process was used to change the degree of saturation while capturing the intended properties. The different capillarity and the corresponding distribution of the water phase in pore space driven by the surface wettability greatly influenced the thermal and electrical conduction behaviors of the sands at unsaturated conditions.