## 2 Materials and Methods
### Main Research
#### 3.2.6 Chemical Resistance Tests  
The test results are presented in Table 13. The table shows the values of average maximum weight loss, the loss of compressive and bending strength, after maintaining the samples in aggressive environments (NaCl, HCl, and Na\({}_{2}\)SO\({}_{4}\)) for 180 days, along with their corresponding coefficients of variation. The basic evaluation criterion, from the point of view of designing building structures, is strength. To visualize the effect of a polyfractional binder on the strength of concrete, Figure 6 shows the percentage ratio of the residual strengths of each type of sample (Types 2-7) in relation to the reference sample. Figure 9 shows the results when holding samples in a NaCl environment, Figure 9 in an HCl environment, and Figure 9 in Na\({}_{2}\)SO\({}_{4}\). \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Parameter**} & \multirow{2}{*}{**Types**} & \multicolumn{3}{c}{**Values**} & \multicolumn{3}{c}{**Variation Coefficients**} \\ \cline{3-7}  & & **NaCl** & **HCl** & **Na\({}_{2}\)SO\({}_{4}\)** & **NaCl** & **HCl** & **Na\({}_{2}\)SO\({}_{4}\)** \\ \hline \multirow{8}{*}{Loss of weight, \%} & 1 & 21.0 & 14.0 & 11.3 & 7.89 & 6.11 & 5.37 \\  & 2 & 17.9 & 12.8 & 10.6 & 5.12 & 4.77 & 3.21 \\  & 3 & 17.9 & 12.2 & 10.3 & 5.63 & 4.88 & 3.55 \\  & 4 & 17.2 & 12.1 & 10.2 & 5.22 & 4.48 & 3.27 \\  & 5 & 14.8 & 11.6 & 9.3 & 5.29 & 4.54 & 3.76 \\  & 6 & 13.3 & 10.1 & 8.7 & 5.08 & 4.12 & 3.52 \\  & 7 & 13.1 & 9.9 & 8.4 & 5.19 & 4.28 & 3.21 \\ \hline \multirow{8}{*}{Loss of compressive strength, \%} & 1 & 45.8 & 17.3 & 12.5 & 12.56 & 8.78 & 9.21 \\  & 2 & 37.8 & 15.2 & 11.1 & 10.98 & 6.09 & 7.54 \\ \cline{1-1}  & 3 & 37.3 & 15.1 & 10.9 & 11.34 & 6.12 & 6.31 \\ \cline{1-1}  & 4 & 37.1 & 14.0 & 10.7 & 10.29 & 5.67 & 7.02 \\ \cline{1-1}  & 5 & 36.1 & 13.9 & 7.2 & 10.07 & 5.93 & 6.32 \\ \cline{1-1}  & 6 & 33.2 & 13.1 & 6.4 & 9.32 & 5.52 & 5.78 \\ \cline{1-1}  & 7 & 33.0 & 12.2 & 6.2 & 9.34 & 5.18 & 5.83 \\ \hline \hline \end{tabular}
\end{table} 
Table 13: Results of chemical resistance tests. Figure 8: Residual weight and strength values after durability tests: (**a**) Residual weight, compressive strength, and bending strength after freeze–thaw cycling in NaCl solution; (**b**) Residual values after freeze–thaw cycling in HCl solution; (**c**) Residual values after freeze–thaw cycling in Na\({}_{2}\)SO\({}_{4}\) solution. The results of the study on the resistance of concrete samples to aggressive environments, in terms of changes in average weight, bending strength, and compressive strength, indicate that Type 2-4 samples, based on a two-component binder, demonstrated higher chemical resistance compared to the reference samples. When maintained in a 3% NaCl solution, the residual weight and strength of these samples were significantly higher than those of the reference samples: the weight varied from 14.7 to 18.3%; compressive strength ranged from 17.6 to 19.1%; and bending strength fluctuated from 15.7 to 16.3%. However, these parameters are worse (i.e., higher) than those of the three-component compositions of Types 5-7, relative to the reference samples: the mass varied from 29.8 to 37.7%; compressive strength ranged from 21.3 to 28.0%; and flexural strength varied from 26.9 to 34.0%. The lower values of chemical resistance observed in Type 2-7 compositions can likely be explained by the fact that the finely dispersed fraction of 4500 cm\({}^{2}\)/g, while promoting the hydration of the binder and leading to higher compressive strength at early stages of