## 3 Results and Discussion
### Thermal Resistance, Conductivity, and Diffusivity
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & \multicolumn{4}{c}{**R1 CEBs**} & \multicolumn{4}{c}{**R2 CEBs**} \\ \cline{2-9}  & \(\gamma_{\text{d}}\) & **R-Value** & \(\lambda\) & \(\alpha\) & \(\gamma_{\text{d}}\) & **R-Value** & \(\lambda\) & \(\alpha\) \\  & [kg/m\({}^{3}\)] & **[m\({}^{2}\)K/W]** & **[W/mK]** & **[m\({}^{2}\)/s]** & **[kg/m\({}^{3}\)]** & **[m\({}^{2}\)K/W]** & **[W/mK]** & **[m\({}^{2}\)/s]** \\ \hline \multirow{3}{*}{28 days} & \multirow{3}{*}{\(1682.16\pm\)} & \multirow{3}{*}{\(0.023\pm\)} & \multirow{3}{*}{\(0.051\pm\)} & \multirow{3}{*}{\(\pm\) 2.52 \(\times\)} & \multirow{3}{*}{\(1830.98\pm\)} & \multirow{3}{*}{\(0.010\pm\)} & \multirow{3}{*}{\(0.0232\pm\)} & \multirow{3}{*}{\(0.653\pm\)} & \multirow{3}{*}{\(4.04\times 10^{-7}\)} \\  & & & & & & & & \(\pm\) 2.56 \(\times\) \\ \cline{1-1} \cline{6-10}  & \multirow{3}{*}{\(4.78\) (\(0.28\%\))} & \multirow{3}{*}{\(0.023\)} & \multirow{3}{*}{\(0.039\)} & \multirow{3}{*}{\(10^{-8}\)} & \multirow{3}{*}{\(1.70\%\)} & \multirow{3}{*}{\((4.31\%)\)} & \multirow{3}{*}{\((4.66\%)\)} & \multirow{3}{*}{\((6.33\%)\)} \\  & & & & & & & & \\ \cline{1-1} \cline{6-10}  & \multirow{3}{*}{\(1733.67\pm\)} & \multirow{3}{*}{\(0.299\pm\)} & \multirow{3}{*}{\(0.050\pm\)} & \multirow{3}{*}{\(0.045\)} & \multirow{3}{*}{\(\pm\) 2.76 \(\times\)} & \multirow{3}{*}{\(1842.59\pm\)} & \multirow{3}{*}{\(0.010\pm\)} & \multirow{3}{*}{\(0.027\)} & \multirow{3}{*}{\(\pm\) 1.72 \(\times\)} \\  & & & & & & & & \\ \cline{1-1} \cline{6-10}  & \multirow{3}{*}{\(15.64\)} & \multirow{3}{*}{\((0.90\%)\)} & \multirow{3}{*}{\((8.55\%)\)} & \multirow{3}{*}{\((8.90\%)\)} & \multirow{3}{*}{\((8.37\%)\)} & \multirow{3}{*}{\(4.75\) (\(0.26\%\))} & \multirow{3}{*}{\((4.13\%)\)} & \multirow{3}{*}{\((4.11\%)\)} & \multirow{3}{*}{\((10^{-8}\)} \\ \cline{1-1} \cline{6-10}  & \multirow{3}{*}{\((4.32\%)\)} & \multirow{3}{*}{\((4.13\%)\)} & \multirow{3}{*}{\((4.32\%)\)} & \multirow{3}{*}{\((4.32\%)\)} & \multirow{3}{*}{\((4.32\%)\)} \\ \hline \hline \end{tabular}  
\({}^{1}\) This table shows the average data with its standard deviation and, in brackets, the coefficient of variation.  
\end{table} 
Table 6: Thermal attributes of R1 (finer-grained) and R2 (coarser-grained) CEBs \({}^{1}\). The estimated thermal characteristics fall within the intervals reported in the literature. Thermal conductivity values for unfired stabilised CEBs generally range between 0.40 and 1.20 W/mK, heat capacity between 870 and 1180 J/kgK, and thermal diffusivity between \(3.02\times 10^{-7}\) and \(4.82\times 10^{-7}\) m\({}^{2}\)/s [39; 45]. Consistent with previous studies on earth-based building materials [7; 46; 47; 48; 49; 50], the observed trend is a decrease in thermal conductivity in blocks with lower bulk density (Figure 8). It can be stated that less dense blocks generally have a higher porosity. In dry conditions, air-filled porosity reduces the thermal conductivity of the blocks due to the inherently low thermal conductivity of air. Therefore, dry density and porosity considerably affect dry soils' conductivity, as heat transfer only depends on the physical contact between the soil particles [38]. Although, in this case, one can refer to an inverse linear relationship, as soon as an increase in humidity is considered, thermal conductivity increases in a non-purely linear trend [41]. Neglecting the water component may have led to an underestimation of the results. The evaluation of effective thermal parameters is still a challenge in soil science. Considering the discussion presented so far, future studies will be focused on modelling the effective thermal parameters of blocks and conducting parametric analyses on wall systems, considering the standard variations in the moisture content. Figure 8: Bulk density vs. thermal conductivity of the two batches of CEBs at both ages. Figure 7: Simplified heat transfer mechanism in dry conditions: finer-grained soils **(left)** have a greater surface area than coarser-grained soils **(right)**.