## 3 Results and Discussion
### Thermal Conductivity  
The analysis of variance for the thermal conductivity, is presented in Table 10. Note that the amount of foam makes a greater contribution to this property, followed by the type of cement and the type of additive. The interaction between the type of cement and the amount of foam exerted a greater influence on the thermal conductivity of the foam blocks.  
In Figure 9a, the thermal conductivity can be observed in relation to the types of cements. The higher the number of pores observed in the blocks made with CP II-F, the lower the thermal conductivity.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Factor**} & **Sum of** & **Degrees of** & **Mean of** & & & \\  & **Squares** & **Freedom** & **Squares** & & & \\ \hline Cement Type (CT) & 0.43250 & 2 & 0.21625 & 15.9986 & 0.0000 & 7.0 \\ Foam Amount (FA) & 1.59326 & 2 & 0.79663 & 58.9368 & 0.0000 & 25.7 \\ Additive Type (AT) & 0.33054 & 3 & 0.11018 & 8.1513 & 0.0000 & 5.3 \\ CT*FA & 1.91944 & 4 & 0.47986 & 35.5013 & 0.0000 & 31.0 \\ CT*AT & 0.21060 & 6 & 0.03510 & 2.5968 & 0.0246 & 3.4 \\ FA*AT & 0.27106 & 6 & 0.04518 & 3.3423 & 0.0058 & 4.4 \\ CT*FA*AT & 0.46158 & 12 & 0.03846 & 2.8457 & 0.0029 & 7.5 \\ Error & 0.97320 & 72 & 0.01352 & & & 15.7 \\ Total & 6.192 & 107 & & & & 100.0 \\ \hline \hline \end{tabular} \({}^{*}\) Interaction between factors.  
\end{table}
Table 10: Analysis of variance for thermal conductivity (28 days of curing).  
Figure 8: Average air void diameter based on D10, D50, and D90 for all specimens.  
Figure 9b shows that increasing the amount of foam reduces the thermal conductivity, as expected, since, during low humidity, the air inside the pores behaves like thermal insulation.  
The isolated influence of the additive type on the thermal conductivity can be seen in Figure 9c. The results show that the best thermal performance was obtained in the specimens made without additives.  
The results show that, due to air being trapped in the structure of foamed concrete, there is a reduction in the transfer and absorption of heat in relation to traditional concrete, thus altering its thermal properties. For example, its thermal conductivity is reduced [69]. According to [PERSON] et al. [70], the thermal conductivity of the material decreased linearly as the porosity in the concrete matrix increased, regardless of the location of the pores. The pore structures of the lightweight concrete with incorporated air become better with thermal insulation when compared to the conventional concretes, because thermal conductivity is directly related to the number and distribution of the pores in the concrete. The values of thermal conductivity are directly influenced by the specific mass of the material, that is to say, light concretes, which have a specific mass varying between 250 and 800 kg/m\({}^{3}\), provide excellent thermal insulation. Another factor that can influence thermal conductivity is humidity, because the lower the saturation of the concrete in the hardened state, the lower the thermal conductivity. However, an increase in moisture content in lightweight concrete results in an increase in thermal conductivity [49].