## 3 Research Results and Discussion
The reserve of porous space, which defines the amount of reserve pores and capillaries through which water or plastic ice penetrates with great difficulty, but gradually fills up during cyclic freezing and thawing, varied from 57.2-80.5%. Effective porosity, which describes the effective pores of the specimen and the capillary potential, i.e., those pores and capillaries that are easily filled with water, varied from 8.8-12.2%, and the total open porosity index, which characterises the entire open communicating pore space of the composite specimen, varied from 23.7-46.4%. The predicted service life of materials suitable for unprotected use under direct exposure to aggressive environmental conditions, characterised by high values of pore space reserve (54-71%), but low values of effective porosity (2-3%) and total open porosity (5-9%), varies from 722 to 1263 conditional cycles [38]. It is also stated that the values of the beginning and end of the decomposition of individual compositions are close. Therefore, when evaluating the durability potential of LWC specimens containing porous aggregates, despite the high values of pore space reserve and the high predicted in-service cold resistance based on the end of degradation (but considering the higher values of effective porosity, total open porosity, and the wide range of start and end values of the individual composition interval), it can be said that such LWC (1-6 mixture compositions) can be used  
Figure 8: Predicted operational cold resistance values for the conditional cycles at the start of decomposition and the end of decomposition: 1–6—composition number of the LWC (see Table 6). in moderately aggressive environmental conditions, i.e., in structures protected from direct environmental impacts. The direct cold resistance of the thermal insulation LWC specimens was evaluated according to changes in their compressive strength, comparing the compressive strength of the control specimens and specimens that were frozen and thawed for 25, 100, and 200 cycles by volume freezing and thawing according to the LST 1428-17 [36] methodology. The results of compressive strength determined from the control specimens and after 25, 100, and 200 freezing and thawing cycles are presented in Figure 9; the calculated changes in compressive strength are presented in Table 8.  
Evaluating the obtained results, Figure 9 and Table 8 show that the decrease in the compressive strength of the specimens with EG aggregate, after 25 and 100 cycles of freezing and thawing, is uniform and small, with the values of \(\Delta f\) varying from 0.0 to 3.6%. Here, the decrease in compressive strength of the samples after 200 cycles of freezing and thawing is large and the values of \(\Delta f\) vary from 20.5-25.0%. Figure 9: Compressive strength of the control specimens and after 25, 100, and 200 freeze–thaw cycles. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{
\begin{tabular}{c} **Composition** \\ **Codes** \\ \end{tabular} } & \multicolumn{3}{c}{**Change in Compressive Strength \(\Delta f\), \%**} \\ \cline{2-4}  & **After 25** & **After 100** & **After 200** \\  & **Freeze–Thaw Cycles** & **Freeze–Thaw Cycles** & **Freeze–Thaw Cycles** \\ \hline \hline \multicolumn{4}{c}{**Specimens with EG aggregate**} \\ \hline
1 & 2.3 & 2.3 & 25.0 \\ \hline
2 & 0 & 0 & 23.3 \\ \hline
3 & 3.6 & 3.6 & 20.5 \\ \hline \hline \multicolumn{4}{c}{**Specimens with EG and CEPW aggregates**} \\ \hline
4 & 9.1 & 18.2 & 24.2 \\ \hline
5 & 6.0 & 14.9 & 17.9 \\ \hline
6 & 2.0 & 2.0 & 8.2 \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Changes in compressive strength after 25, 100, and 200 freeze–thaw cycles. The reduction in compressive strength of the specimens with EG and CEPW aggregate after 25 freeze-thaw cycles was greater, the maximum value of \(\Delta f\) being 9.1%. After 100 freeze-thaw cycles, the maximum value of \(\Delta f\) was 18.2% and after 200 freeze-thaw cycles and defrosting cycles, the maximum value of \(\Delta f\) reached 24.2%.