A study on the thermal conductivity of compacted bentonites

TL;DR

This study investigates how factors like dry density, water content, and soil composition affect the thermal conductivity of compacted bentonite, crucial for designing radioactive waste repositories, and proposes a predictive linear correlation.

Contribution

It introduces a new linear correlation model for predicting thermal conductivity based on volumetric air fraction in compacted bentonite.

Findings

Thermal conductivity increases with dry density and water content.

The proposed correlation accurately predicts thermal conductivity across different conditions.

Comparison shows the new model aligns well with existing methods.

Abstract

Thermal conductivity of compacted bentonite is one of the most important properties in the design of high-level radioactive waste repositories where this material is proposed for use as a buffer. In the work described here, a thermal probe based on the hot wire method was used to measure the thermal conductivity of compacted bentonite specimens. The experimental results were analyzed to observe the effects of various factors (i.e. dry density, water content, hysteresis, degree of saturation and volumetric fraction of soil constituents) on the thermal conductivity. A linear correlation was proposed to predict the thermal conductivity of compacted bentonite based on experimentally observed relationship between the volumetric fraction of air and the thermal conductivity. The relevance of this correlation was finally analyzed together with others existing methods using experimental data on several compacted bentonites.