# Water Impermeability of Self-Compacting Fly-Ash-Containing Concrete
## 4 Conclusions  
1. The results of the experiments showed the possibility of reducing cement consumption up to 20-23% by adding the optimal amount of fly ash to the composition of self-compacting concrete while ensuring the required strength.
2. Additional grinding of the ash to the optimum specific surface area allows for additional savings in cement of 8-10%.
3. For compositions of self-compacting concrete containing fly ash additive with different specific surface areas, a set of experimental/statistical models of mixture water separation, strength, and water impermeability of concrete was obtained.
4. Analysis of the obtained models allowed us to obtain quantitative estimates of the influence of the main technological factors and their interactions on the studied properties of self-compacted concrete.
5. A high level of correlation between the impermeability and strength of concrete was established, which allowed us to propose an empirical equation for predicting impermeability. Experimental verification showed the possibility of using this equation to predict water resistance with sufficient accuracy.  
Conceptualization, L.D. and O.B.; methodology, O.B.; software, O.B. and D.M.; validation, L.D., T.T. and M.S.; formal analysis, M.S. and T.T.; investigation, L.D. and O.B.; resources, L.D. and O.B.; data curation, L.D. and D.M.; writing--original draft preparation, L.D. and O.B; writing--review and editing, M.S. and T.T.; visualization, O.B. and M.S.; supervision, L.D. and  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**No.**} & \multirow{2}{*}{**Compressive Strength, MPa**} & \multicolumn{2}{c}{**Experimental Water**} & \multicolumn{2}{c}{**Calculated Water**} & \multirow{2}{*}{**Accuracy, \%**} \\  & & **Impermeability Value, MPa** & & **Impermeability Value** \\  & & & **by Equation (9), MPa** & \\ \hline
1 & 33.8 & 0.65 & 0.63 & \(-\)2.6 \\ \hline
2 & 57.6 & 0.92 & 1.00 & 8.3 \\ \hline
3 & 60.1 & 0.99 & 1.04 & 4.6 \\ \hline
4 & 54.0 & 1.01 & 0.95 & \(-\)6.2 \\ \hline
5 & 70.2 & 1.11 & 1.20 & 7.2 \\ \hline
6 & 53.9 & 0.85 & 0.95 & 10.4 \\ \hline
7 & 28.9 & 0.57 & 0.56 & \(-\)2.9 \\ \hline
8 & 65.5 & 1.19 & 1.13 & \(-\)5.6 \\ \hline
9 & 68.9 & 1.13 & 1.18 & 3.9 \\ \hline
10 & 48.2 & 0.94 & 0.86 & \(-\)9.1 \\ \hline Average & & & & \(\pm\)6.1 \\ \hline \hline \end{tabular}
\end{table}
Table 6: Experimental and calculated values of water impermeability of self-compacting concrete.  
T.T.; project administration, D.M.; funding acquisition, D.M. All authors have read and agreed to the published version of the manuscript. The research was supported by the Polish National Agency for Academic Exchange under the complementary activities to those undertaken by the university as part of the University Alliance European entitled STARS EU academic cooperation with Ukrainian universities, grant no. BNI-UE-2023-8. Institutional Review Board Statement: Not applicable. Informed Consent Statement: Not applicable. Data Availability Statement: Raw data were generated at the National University of Water and Environmental Engineering in Ukraine and Cracow University of Technology. Derived data supporting the findings of this study are available from the corresponding author on request. Conflicts of Interest: The authors declare no conflicts of interest.