Experimental Study on the Thermal Conductivity of Compacted SPV200 Bentonite

Abstract

This study employed two thermal conductivity measuring techniques, including the needle probe-based transient needle-probe method in accordance with ASTM 5334-14 and the surface probe-based transient plane source method in compliance with ISO 22007-2:2015, to examine the thermal conductivity of compacted SPV200 bentonite. The effects of temperature, water content, and dry density on the thermal behavior of SPV200 bentonite were extensively investigated. The test results indicate: (1) thermal conductivity measured by the two methods agreed well, while the transient plane source method exhibited good efficiency; (2) the thermal conductivity of compacted SPV200 increases with water content, dry density, and temperature; (3) three-dimensional representations of the thermal conductivity of SPV200 bentonite as functions of dry density, water content, and temperature were generated to illustrate a clear relationship among them; (4) two multi-parameter models for predicting thermal conductivity of compacted SPV200 bentonite were proposed, and both showed good fits to the experimental data. The results provide a practical approach to the prediction of thermal properties of compacted bentonite, which can be helpful in the coupled thermo-hydro-mechanical analysis of buffer materials.