## 3 Research Results and Discussion
Then, an analysis of the effect of CEPW on the bending strength of the specimens was carried out. A comparison of the flexural strength results was only made when the EG aggregate was used and when part of the EG was replaced with the CEPW aggregate. Analysis indicates that the differences in the results are not significant. The obtained average values of flexural strength meet the 95% confidence interval, and this indicates that the replacement of the EG aggregate with the CEPW aggregate does not influence flexural strength (or that the influence is insignificant). To summarise the results, it can be stated that replacing the EG aggregate with the CEPW aggregate does not affect the strength parameters. The macrostructural studies of the LWC specimens are presented in Figure 5. The purpose of the study was to evaluate the effect of the CEPW aggregate on the macrostructure of the LWC and to explain its effects on the strength characteristics and thermal conductivity. Figure 5a shows a general view of the LWC when only EG aggregate is used, and Figure 5b shows when the 0-2 mm fraction of EG is replaced by CEPW. In the first case, we observe  
Figure 4: Dependence of the bending strength on density (**a**) and analysis of the effect of CEPW on the bending strength (**b**). the formation of large voids in the LWC structure. The width of the spaces in the individual zones exceeds 5 mm. Through these voids, intensive heat transfer through the air can occur. Meanwhile, the EG aggregates themselves are well connected to each other by the touching surfaces, which allows us to ensure sufficient strength of the LWC. In the second case, we observe that almost all voids are filled with CEPW. Very small gaps were formed between the CEPW aggregates themselves, which are even smaller than the pores formed between the EG aggregates themselves. This good filling is due to the fact that the CEPW aggregate is very soft and fits well between the larger EG aggregates and so, in most cases, the CEPW aggregate appears slightly deformed. Deformation is likely to occur during compaction, so good void filling was observed, and there were no gaps between CEPW and EG. Since CEPW aggregates are soft and mechanically damaged during crushing, mixing, and compaction, their influence on the strength of LWC is unobservable or very insignificant. In addition, as already mentioned, EG aggregates are well connected to each other by their contact surfaces, and so the load primarily affects the EG aggregate, which has a significantly higher strength than CEPW. The operational properties of LWC products, particularly the resistance to freezing and thawing, are closely related to the effects of water. In this work, we evaluated the effect of water on LWC by long-term immersion in water and moisture deformations. In Figure 6a, the dependence of the long-term water absorption of the specimens on the density is presented. The figure shows that the long-term water absorption of  
Figure 5: View of the macrostructure of LWC: (**a**) with the EG aggregate; (**b**) with the EG and CEPW aggregate. LWC decreases with increasing density. The test results are described by the regression Equation (16):  
Figure 1:0  
where the determination coefficient \(r^{2}=0.812\) and standard deviation \(S_{r}=1.078\%\). The upper limit of the results is indicated by the dashed line in Figure 6, calculated with a 95% confidence interval. The resulting dependence shows that, with a 1.5-times increase in LWC density, the long-term absorption decreases by approximately 1.41 times; by increasing the LWC density by 1 kg, the long-term absorption decreases by approximately 0.057%. Figure 6b shows the evaluation of the effect of the CEPW on the water absorption of the specimens. Analysis shows that there is almost no difference in the results when there is only EG aggregate or when part of the EG aggregate is replaced by CEPW aggregate. In both cases, the average values of the results are similar and close to the overall average of the results.