## 3 Results
In type B compositions, the pattern of changes in compressive strength differs compared to changes in the strength of type A compositions. Additionally, note that, in general, the addition of potassium feldspar provides higher values of compressive strength compared to type A compositions, where the addition of micro calcite was used. Therefore, when replacing a part of the binder with the addition of potassium feldspar in the amount of 5%, the compressive strength value increased from 34.1 MPa to 41.5 MPa. As for the compositions of the 7B, 8B, 9B, and 10B types, the values of their strengths changed insignificantly and were equal to 51.6 MPa, 52.2 MPa, 51.8 MPa, and 51.7 MPa, respectively, but, as in the first case, the maximum value of the compressive strength was recorded for the geopolymer composite where part of the binder was replaced with 15% potassium feldspar additive. A further increase in the dosage of this additive may be irrational due to the fact that the Si/ Al ratio remains practically unchanged, leaving the strength indicators at the same level or less than at a dosage of 15%. As shown in Figure 8, the maximum tensile strength of 6.7 MPa in bending was observed similarly to the compressive strength of the 8B composition, and the geopolymer composite of the control composition had the lowest bending tensile strength of 4.0 MPa. In general, the pattern of changes in tensile strength in bending is the same as for compressive strength. Therefore, for compositions of types 1A, 2A, 3A, 4A, and 5A, the tensile strength values in bending were 4.5 MPa, 5.5 MPa, 5.6 MPa, 5.1 MPa, and 4.6 MPa, respectively. Additionally, for compositions of types 6B, 7B, 9B, and 10B, the tensile strength values in bending were 5.1 MPa, 6.5 MPa, 6.6 MPa, and 6.6 MPa, respectively. An increase in the strength characteristics of a geopolymer composite with the use of various types of stone flour is ensured by an increase in the rate of the geopolymerization reaction, which contributes to the accelerated dissolution of the aluminosilicate component and the formation of an aluminosilicate gel and the chemical interaction of an aluminosilicate gel with particles of undissolved aluminosilicate, leading to the formation of complexes of \"gel-like layer-undissolved material grain\". Thus, the introduction of micro calcite and potassium feldspar additives into the composition of fine-grained geopolymer concrete led to increases in strength characteristics (\(\Delta R_{b}\) and \(\Delta R_{bttb}\)), which are indicated in Table 10.  
Figures 9 and 10 show the values of the test results for cube specimens in terms of \"compressive strength\". \begin{table}
\begin{tabular}{c c c c c} \hline
**Composition Title** & \(R_{b}\)**, MPa** & \(R_{bttb}\)**, MPa** & \(\Delta R_{b}\)**, \%** & \(\Delta R_{bttb}\)**, \%** \\ \hline C & 34.1 & 4.0 & 0 & 0 \\
1A & 36.8 & 4.5 & +8 & +12 \\
2A & 45 & 5.5 & +32 & +37 \\
3A & 46.6 & 5.6 & +36 & +40 \\
4A & 42.7 & 5.1 & +25 & +28 \\
5A & 36.7 & 4.6 & +8 & +15 \\
6B & 41.5 & 5.1 & +22 & +27 \\
7B & 51.6 & 6.5 & +51 & +62 \\
8B & 52.2 & 6.7 & +53 & +68 \\
9B & 51.8 & 6.6 & +52 & +65 \\
10B & 51.7 & 6.6 & +51 & +65 \\ \hline \end{tabular}
\end{table} 
Table 10: Increases in strength characteristics of fine-grained geopolymer concrete depending on the dosage of micro calcite and potassium feldspar. The values of the calculated softening factors are presented in the form of a diagram in Figure 11.  
According to the data obtained, samples of experimental fine-grained geopolymer concrete with various types and dosages of stone flour demonstrated almost identical results of the softening coefficient. At the same time, the values of \(K_{soft}\) were close to 1, which indicates that there was no negative effect of the aquatic environment on the strength characteristics of the geopolymer composite.