Investigating the Thermal Conductivity of Compacted Earth Blocks Versus Density and Moisture Content

Earth-based building materials offer promising potential for reducing the environment footprint of construction projects, due to their low energy requirements during production and the prospect of post-lifecycle reusability when not stabilized. In this study, we focus on thermal and hygric performances of compacted earth blocks (CEBs). This research aims to analyze the impact of density and water content on the thermal conductivity of CEBs. Within this framework, cylindrical samples of compacted and unstabilized earth, formulated by Laboratoire CBTP, are manufactured using fines from quarries, targeting three distinct densities ranging from 1.90 to 2.15 g/cm3. Thermal conductivity measurements are conducted at different moisture levels for each density using the transient hot-wire methodology. At the dry state, thermal conductivity values range from 0.8 to 1.1 W/(m.K). The experimental results show a linear correlation between thermal conductivity and both density and moisture content. A simple model based on the combined effect of the degree of saturation and the dry density of the material is applied to model the moisture-dependent thermal conductivity.