Assessing the effects of soil grading on the moisture content-dependent thermal conductivity of stabilised rammed earth materials

New data for both the dry-state and the moisture content-dependent thermal conductivity of cement-stabilised rammed earth (SRE) materials is presented. For highly compacted SRE materials, no correlation was found between thermal conductivity and dry density or void ratio. The thermal conductivity of SRE materials increases linearly with the saturation ratio, Sr of the material and can be expressed as λ∗, the moisture content-dependent thermal conductivity. The sensitivity of λ∗ to an increase in the saturation ratio of SRE materials varies according to soil grading. The influence of grading parameters on λ∗ can cause material variations of approximately 0.8 m2 K/W. The experimental data has been applied to standard SRE wall design configurations and the effect of wall moisture content on the total thermal resistance has been shown. The R-value of an SRE wall irrespective of cavity insulation can vary by as much as 0.13 m2 K/W.