## 5 Discussion  
The popularization of cement-stabilized rammed earth as a building material that is in direct competition with concrete requires the development of standards for determining compressive strength classes similar to those determined for concrete. The obtained results showed that the compressive strength of CSRE specimens should be carried out for a period longer than 28 days, as specified in the standard for concrete EN 206 [31]. The cubic specimens tested after this time obtained a compressive strength equal to 63% to 73% of the strength of 120 day specimens. The nature of the CSRE compressive strength growth curve is much different from that of concrete. It is also noted that after 120 maturing data points, the results of the compressive strength of the core and cubic specimens were similar and differed by less than 1 MPa. Density over 2200 kg/cubic meter is significantly higher than the minimum tested in other studies [21; 42; 56], where approximately 1800 kg/cubic meter is the minimal value guaranteeing proper UCS values. It could be an explanation for the vastly higher values of destructive forces measured in this study in compression, as the dependence of UCS on dry density is well documented [57; 58; 59]. Comparisons of UCS between cube-shaped and cored specimens of different mixtures of cement-stabilized rammed earth initially may reveal a small advantage in mechanical properties in favor of cube ones. The mean averages for specimens except for 433-6% were higher than their cored counterparts. Ratios for mean UCS vary from 1.001 to 1.119, which represents values from 0.01 to 1.51 MPa in these cases, but analysis of variance \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \(\SS_{\mathit{btw}}\) & \(df_{\mathit{futw}}\) & \(\MS_{\mathit{btw}}\) & \(\SS_{\mathit{tot}}\) & \(df_{\mathit{tot}}\) & \(\MS_{\mathit{btw}}\) & \(F\) & \(p\) \\ \hline
1.45161 & 1 & 1.45161 & 5.4008 & 8 & 0.6751 & 2.15021478 & 0.180723 \\ \hline \hline \end{tabular}
\end{table} 
Table 18: Results of ANOVA for 433-9 cu vs. 433-9 cr. failed to prove that the achieved results are statistically different. Tests conducted on an atypical outlier, that is, a mixture of 433-6%, inversely revealed cored specimens with better mechanical properties, achieving 9.21 M1 Pa of compressive strength. It seems important to stress that for mixtures with 9% stabilizer, the difference between specimens is visibly more highlighted, reaching 0.82 and 1.51 MPa for 433 and 703 mixtures, respectively. This disparity is reduced in specimens with only 6% of cement, as it reaches only 0.34 MPa for mixture 433 and 0.01 for mixture 703. The need for safety factors in order to erect CSRE construction in a moderate climate is obvious, as it seems unreasonable to base this technology on in situ, long-lasting testing. The provided analysis made it noticeable that a coefficient factor between cube specimens UCS and cored ones' is not necessary, and tests and research to date failed to find any statistically significant difference between the mean values of the compressive strength for the 433-9 and 703-6 mixtures. As far as the study is concerned, estimating UCS for CSRE within any construction element based on laboratory testing of a mixture specimen is not viable. The confidence interval shown in Figures 19 and 20 defines the range where, with 95% probability, the \"real\" mean can be located. The quotation mark used for \"real\" means it needs explanation. The mean values presented in these figures are based on the results of the tests. When the normality of the samples is confirmed at the confidence level \(\alpha=0.05\) the confidence intervals can be calculated and presented. This means that if more cube samples are prepared (samples marked as cu in these figures) or more core samples (cr) are drilled off the structure, the mean of the compressive strength, as we can expect, will be within the range stated by the confidence intervals.