Effect of Fines on Thermal Conductivity of Dry Sand-Kaolin Mixture

Soil thermal conductivity k plays a crucial role in analysis and design of different systems that rely on thermal interaction with the ground. Research indicates a significant difference between k values estimated using transient-state and steady-state methods. Apart from the rate of soil temperature increment, soil composition also influences the difference between transient-state thermal conductivity k(tr) and steady-state thermal conductivity k(st). Such a deviation of k(st) from ktr of sand-kaolin mixture is overlooked in the literature. This research focuses on the influence of fines percentage on thermal conductivity of sand-kaolin mixtures. A specially designed consolidometer, which is capable of measuring both k(st) and k(tr) from soil temperature profile derived from a single test, was used in this research. Results demonstrate that the percentage of fines filling the pore space significantly influences heat conduction, and thereby effective thermal conductivity of the mixture.