## 2 Materials and Methods  
To study the impact of a combination of different types of fibers on the strength and deformation characteristics of fiber-reinforced concrete, a program of experimental studies was developed. The block diagram of the experiment program is shown in Figure 1.  
During the research, the no-additive Portland cement of the PC500 D0 brand produced by OAO \"Novoroscement\" was used. Table 1 shows Portland cement's physical and mechanical characteristics, and Table 2 shows the chemical and mineralogical composition of Portland cement. River sand was used as a fine aggregate in accordance with GOST 8736 \"Sand for construction works. Specifications\" [44]. The granulometric composition of the sand is presented in Table 3, and the main physical and mechanical characteristics are presented in Table 4. \begin{table}
\begin{tabular}{c c} \hline \hline
**Indicator Title** & **Value** \\ \hline Specific surface area (according to Blaine) & \(\geq\)340 m\({}^{2}\)/kg \\ Oversize product \# 008 & \(\leq\)3.5\% \\ Mortar standard consistency, \% & \(\leq\)26.5 \\ Setting time, hour-min: & not earlier 2–00 \\ - start - finish & not later 6–00 \\ Tensile strength during the bending test, MPa: & \\ - 2 days & \(\geq\)4.0 \\ - 28 days & \(\geq\)6.0 \\ Compressive strength, MPa: & \\ - 2 days & \(\geq\)21.0 \\ - 28 days & \(\geq\)52.0 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Characteristics of Portland cement PC500 D0. Figure 1: Block diagram of the experiment program. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Scheme** & \multicolumn{5}{c}{**Sieve Diameter, mm**} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} \\
**Scheme** & **2.5** & **1.25** & **0.63** & **0.315** & **0.16** & **\textless{}0.16** & **\textless{}0.16** & **\textless{}0.16** \\ \hline partial & 1.89 & 4.71 & 24.52 & 59.18 & 6.67 & 0.31 & 2.27 \\ full & 1.89 & 6.60 & 31.13 & 90.30 & 96.97 & 0.31 & 2.27 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Physical and mechanical properties of sand. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Center of Dust and** & **Clay Content in** & **Clay Content in** & **Bulk Density, kg/m\({}^{3}\)** & **True Density, kg/m\({}^{3}\)** & **The Organic** \\
**Clay Particles, \%** & **Lumps, \%** & **Bulk Density, kg/m\({}^{3}\)** & **True Density, kg/m\({}^{3}\)** & **Inclusions Presence** \\ \hline
0.7 & 0.16 & 1632 & 2650 & absent \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Physical and mechanical properties of fiber (data were received from manufacturer). Figure 3: Basalt fiber (scale 1:1). Figure 2: Steel fiber (scale 1:1). \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Fiber Type** & **Tensile** & **Trength, MPa** & **Fiber Diameter, m** & **Fiber Length, mm** & **Elastic Modulus GPa** & **Density, g/cm\({}^{3}\)** & **Elongation Ratio, \%** \\ \hline Basalt & 3500 & \(16\times 10^{-6}\) & 12 & 3500 & 2.6 & 3.2 \\ Polypropylene & 500 & \(15\times 10^{-6}\) & 20 & 35 & 0.91 & 120 \\ Steel & 1500 & \(0.3\times 10^{-3}\) & 30 & 190 & 7.8 & 3 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Physical and mechanical properties of fiber (data were received from manufacturer). The superplasticizer Schomburg Remicrete SP-10 (FM) was used to regulate the mobility of concrete mixtures. It is a highly effective polyester carboxylate-based plasticizer that contributes to accelerated early and final strength development by acting on the hydration processes. The technical characteristics of the superplasticizer are shown in Table 6.  
All samples were made of fine-grained concrete of the same composition Cement/Sand = 1:2 at Water/Cement = 0.32 and the consumption of the superplasticizer additive in the amount of 0.6% of the cement mass. A laboratory concrete mixer BL-10 was used (Figure 5). The mixing of the components of the concrete mixture was carried out in the following sequence. At first, sand and Portland cement were loaded into the laboratory concrete mixer.