## 3 Research Results and Discussion
This means that the water absorption is not affected by CEPW. During operations, building materials become wet in the case of higher relative air humidity and dry out in dry periods. During the moisture sorption and desorption processes, most materials expand by absorbing moisture from the surrounding air and shrink by drying. Such a change in material dimensions can cause damage or collapse of  
Figure 1:1 Dependence of the long-term water absorption of the specimens on the density (**a**) and analysis of the effect of CEPW on the water absorption (**b**). structures. In Figure 7, the results of LWC expansion-shrinkage tests with light aggregate are presented. The conducted studies have shown that the use of CEPW aggregate reduces the shrinkage and expansion of the thermal insulation composite, especially at the lowest PC content (70 kg/m\({}^{3}\)). Higher amounts of OPC are likely to result in higher internal stresses, which, in turn, lead to greater expansion or shrinkage. Additionally, it is likely that some of the moisture from the EG is taken up by the CEPW. As CEPW is sufficiently plastic, both drying shrinkage and moisture expansion have no (or negligible) influence on CEPW aggregate dimensions, and CEPW itself reduces internal stresses due to drying or wetting. Drying shrinkage is explained by the loss of moisture in the concrete, usually due to interaction with the surrounding environment, causing internal shrinkage stress, which can lead to cracking and loss of physical and mechanical properties of the concrete [37]. The average values of the structural indicators determined for LWC with EG aggregate and LWC specimens with mixed EG and CEPW aggregate are presented in Figure 1:2  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \begin{tabular}{c} **Composition** \\ **Codes** \\ \end{tabular}  & \begin{tabular}{c} **W\%** \\ **W\%** \\ \end{tabular}  & \begin{tabular}{c} **W\%** \\ **W\%** \\ \end{tabular}  & \begin{tabular}{c} **R\%** \\ **R\%** \\ \end{tabular}  & \begin{tabular}{c} **D, \%** \\ **D\%** \\ \end{tabular}  & \begin{tabular}{c} **G\({}_{1}\), g/cm\({}^{2}\)** \\ **G\({}_{2}\), g/cm\({}^{2}\)** \\ **Units** \\ \end{tabular}  & \begin{tabular}{c} **N, Cond.** \\ **g\({}_{2}\), g/cm\({}^{2}\)**-h** \\ \end{tabular}  & \ \begin{tabular}{c} **g\({}_{2}\), g/cm\({}^{2}\)**-h** \\ **F\({}_{\text{RE1}}\)** \\ \end{tabular}  & \begin{tabular}{c} **F\({}_{\text{RE2}}\)** \\ **F\({}_{\text{RE2}}\)** \\ \end{tabular}  \\ \hline \hline \multicolumn{11}{c}{**Specimens with EG aggregate**} \\ \hline
1 & 10.7 & 25.1 & 57.2 & 3.0 & 0.89 & 0.93 & 1.4 & 0.21 & 230 & 782 \\ \hline
2 & 10.7 & 41.1 & 74.0 & 1.4 & 1.64 & 1.67 & 0.5 & 0.27 & 216 & 1270 \\ \hline
3 & 10.8 & 43.6 & 75.2 & 1.3 & 2.26 & 1.89 & 0.7 & 0.25 &The calculated values of operational cold resistance of the specimens with EG aggregate F\({}_{\text{RE1}}\) varied from 216 to 230 conditional cycles and F\({}_{\text{RE2}}\) varied from 782 to 1539 conditional cycles. For specimens with EG and CEPW aggregate, the values of operational cold resistance F\({}_{\text{RE1}}\) varied from 142 to 268 conditional cycles, and F\({}_{\text{RE2}}\) varied from 727 to 1239 conditional cycles (see Figure 8). By analysing the operational frost resistance values, calculated according to the methodology adapted to predict the frost resistance of porous building materials in a one-sided method [34; 35], we can see that LWC (taking into account the various aggregates used but not their composition) has a relatively high durability potential. The minimum value of the operational cold resistance (\(F_{RE1}\)) of the composite specimens with the EG and CEPW aggregates was 142 conditional cycles and the highest \(F_{RE2}\) was 1539 conditional cycles. In our opinion, the higher durability potential was determined by the porous macrostructure formed by the specimens.