## 3 Results
### Thermal Conductivity and Fire-Resistance  
Thermal conductivity and fire-resistance are important characteristics of extrusion concrete panels, which are used as interior and exterior construction materials. In both experiments, a plain mix with 100% silica powder and an R50 mix with a 50% silica powder-WCP substitution ratio were used in the panel production process. In the case of the thermal conductivity experiment in Figure 11, the panels were cut into a dimension of 300 \(\times\) 300 \(\times\) 50 mm, and HFM436 manufactured by Netzsch \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Test Type**} & \multirow{2}{*}{
\begin{tabular}{c} **Curing** \\ **Level** \\ \end{tabular} } & \multicolumn{5}{c}{**Replacement Ratio (\%)**} \\ \cline{3-6}  & & **Plain** & **25** & **50** & **75** & **100** \\ \hline \multirow{3}{*}{Specific gravity (g/cm\({}^{3}\)) Below 2.0} & Air-dry & 1.90 & 1.95 & 1.97 & 1.99 & 1.99 \\  & Steam & 1.72 & 1.76 & 1.81 & 1.89 & 1.92 \\  & Autoclave & 1.71 & 1.74 & 1.75 & 1.75 & 1.78 \\ \hline \multirow{3}{*}{Absorption rate (\%) Below 18} & Air-dry & 6.52 & 6.65 & 7.18 & 7.15 & 9.20 \\  & Steam & 8.87 & 9.02 & 9.24 & 9.68 & 14.14 \\  & Autoclave & 12.03 & 11.97 & 12.11 & 12.31 & 14.69 \\ \hline \multirow{3}{*}{Length change (\%) Below 0.12} & Air-dry & 0.32 & 0.33 & 0.32 & 0.24 & 0.27 \\  & Steam & 0.19 & 0.19 & 0.17 & 0.12 & 0.13 \\ \cline{1-1}  & Autoclave & 0.07 & 0.06 & 0.07 & 0.07 & 0.10 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Specific gravity, absorption ratio and length change. (Munchen, Germany) was used, in reference to KS M 3808: Foamed polystyrene for thermal insulation. Figure 11 shows the equipment for measuring a thermal conductivity of an extruded panel. The results of the experiment are shown in Table 6. The plain and R50 specimens had similar thermal conductivity: the plain specimen, in which silica powder was used as an aggregate, the thermal conductivity was measured to be 0.30-0.32 (W/m\(\cdot\)K), whereas the specimen, in which 50% of the silica powder was replaced with WCP, had a thermal conductivity of 0.29-0.33 (W/m\(\cdot\)K) [16]. In the case of extrusion concrete panels, fire-resistance is also considered important when they are to be used as an interior material. Fire-resistance performance may not be of significance in this particular study considering its purpose, but an experiment was conducted on fire-resistance in order to examine whether the use of WCP had any impact on the performance of the panels. For the fire-resistance experiment, two pieces of each specimen were assembled into a dimension of 1 \(\times\) 1 m. The fire-resistance testing method for panels is prescribed in KS F 2257-8: Method of fire resistance test for elements of building construction--Specific requirements for non-loadbearing vertical separating elements. The fire-resistance experiment was conducted in accordance with the above standards, and accordingly, the assessment items were divided into flame and thermal interruption performances. In the case of the thermal interruption performance, the time before interrupting the non-heated surface, which is unexposed to the flames, from reaching an average temperature increase of 140 \({}^{\circ}\)C, and the time before interrupting a particular spot from reaching the maximum temperature increase of 180 \({}^{\circ}\)C are specified. On the other hand, as for the flame interruption performance, there should be no heat or red heat on the cotton pads or the flames that exist for more than 10 s, and the crack gauge should not be penetrated [17; 18]. Table 7 and Figure 12 show the results of the fire-resistance experiment performed on the plain and R50 specimens for 120 min under the standard time-heating curve condition. The initial temperature