## 2 Materials and Methods  
Portland cement CEM II/A-S 52.5N was used in the research. The properties of the cement were determined according to [34; 35; 36]. The obtained results are shown in Table 1.  
The chemical compositions of Portland cement and zeolitic tuff (from Sokyrnytsia, Ukraine) were determined using an X-ray spectrometer ARL 9800 XP (Thermo Fisher Scientific, Waltham, MA, USA) and are shown in Table 2. The clinoptilolite content in zeolite was 68%. The properties of aggregates were tested according to [37; 38], and the obtained results are reported in Table 3. The water absorption for crushed granite aggregates was 0.4%. Grading curves for the aggregates are given in Figure 1. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Specific Surface, m\({}^{2}\)/kg**} & \multirow{2}{*}{**Residue on Sieve 008, \%**} & \multirow{2}{*}{**Water Demand, \%**} & \multicolumn{2}{c}{**Setting Time, min**} & \multicolumn{2}{c}{**Compressive Strength, MPa**} \\ \cline{5-6}  & & & **Initial** & **Final** & **2 Days** & **28 Days** \\ \hline
350 & 2.6 & 29.0 & 140 & 230 & 27.1 & 54.2 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Properties of the cement. \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & **Material** & \multicolumn{2}{c}{**CEM II/A-S 52.5N**} & \multicolumn{2}{c}{**Natural Zeolite**} \\ \hline \multirow{5}{*}{**CEM II/A-S 52.5N**} & \multirow{5}{*}{2.63} & SiO\({}_{2}\) & 22.96 & 77.64 \\  & & Al\({}_{2}\)O\({}_{3}\) & 4.85 & 13.04 \\  & & Fe\({}_{2}\)O\({}_{3}\) & 3.59 & 2.90 \\  & & CaO & 60.20 & 4.77 \\  & & MgO & 2.04 & 1.60 \\  & & SO\({}_{3}\) & 2.40 & 0.05 \\  & & LOI & 3.96 & - \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Chemical composition of cement and zeolitic tuff. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Aggregate Type**} & \multirow{2}{*}{**Density**} & \multirow{2}{*}{**Bulk Density**} & \multirow{2}{*}{**Voidage**} & \multirow{2}{*}{**Dust and Clay Particles**} & \multirow{2}{*}{**Fineness**} \\  & [g/cm\({}^{3}\)] & [kg/m\({}^{3}\)] & [\%] & [\%] & [\%] & Modulus \\ \hline Fine (quartz sand) & 2.63 & 1502 & 42.9 & 0.2 & 1.6 \\ \hline Fine (crushed granite sand, & & & & \\
0.63–2 mm) & 2.66 & 1464 & 45.0 & 0.6 & - \\ \hline Coarse (granite gravel, & & & & \\
5–10 mm) & 2.66 & 1428 & 46.3 & 0.2 & - \\ \hline Coarse (granite gravel, & & & & \\
10–20 mm) & 2.66 & 1465 & 44.9 & 0.5 & - \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Properties of aggregates. A commercially available polycarbonate-based superplasticizer with a specific gravity of 1.05 and solid content of 30% and an air-entraining agent with a specific gravity of 1.02 and solid content of 2.5% were used in this study. Polyppropylene (PP) microfibers and fibers with a deformed shape were added to improve the deformation characteristics of concrete. PP fibers were thoroughly scattered to provide an even distribution in the mix. Polypropylene fibers with a deformed shape were used to improve the polymer-concrete bond, because the mechanical bond of ordinary polypropylene fiber with the cement matrix is relatively weak. The properties of PP fibers are given in Table 4.  
A general view of fibers with deformed shape and microfibers can be seen in Figures 2a and 2b, respectively. \begin{table}
\begin{tabular}{c c c} \hline \hline \multirow{2}{*}{**Properties**} & \multicolumn{2}{c}{**Value**} \\ \cline{2-3}  & **Ordinary Polypropylene (PP) Microfiber** & **Polypropylene (PP) Macrofiber with** \\  & & **Deformed Shape** \\ \hline Fiber length & 12 mm & 45 mm \\ Shape of the cross-section & Round (\(\O\) 18 \(\div\) 20 \(\upmu\)m) & Rectangular (1.0 \(\times\) 0.5 mm) \\ Aspect ratio & 630 & 56 \\ Type/form & Micro/monofilament & Macro/monofilament \\ Specific weight & 0.91 g/cm\({}^{3}\) & 0.91 g/cm\({}^{3}\) \\ Melting point & 162 \({}^{\circ}\)C & 164 \({}^{\circ}\)C \\ Flash point & 593 \({}^{\circ}\)C & \textgreater{}550 \({}^{\circ}\)C \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Characteristics of fibers.