## 3 Results
\begin{table}
\begin{tabular}{l c c c c} \hline \hline \multirow{2}{*}{**Sample**} & \multicolumn{2}{c}{**Permeability Coefficient P\({}_{\rm H2}\)**} & \multicolumn{2}{c}{**Diffusion Coefficient D**} & \multicolumn{2}{c}{**Filtration Coefficient k**} \\ \cline{2-5}  & **(cm\({}^{3}\)STP\(\cdot\)cm\(\cdot\)cm\({}^{-2}\cdot\)s\({}^{-1}\cdot\)cmHg\({}^{-1}\))** & **Barrer** & **m\({}^{2}\)/s** & **m\({}^{2}\)** \\  & **s\({}^{-1}\cdot\)cmHg\({}^{-1}\))** & & & **mD** \\ \hline Concrete “2” & 4.170 \(\times\) 10\({}^{-4}\) & 4.170 \(\times\) 10\({}^{6}\) & - & 2.67 \(\times\) 10\({}^{-16}\) \\  & & & & 0.2703 \\ \hline Concrete “1” & 7.804 \(\times\) 10\({}^{-5}\) & 7.804 \(\times\) 10\({}^{5}\) & - & 4.99 \(\times\) 10\({}^{-17}\) \\  & & & & 0.0505 \\ \hline Polymer-concrete “14-3” & 3.414 \(\times\) 10\({}^{-5}\) & 3.414 \(\times\) 10\({}^{5}\) & - & 4.79 \(\times\) 10\({}^{-17}\) \\  & & & & 0.0485 \\ \hline Polymer-concrete “G1” & 6.214 \(\times\) 10\({}^{-5}\) & 6.214 \(\times\) 10\({}^{5}\) & - & 7.48 \(\times\) 10\({}^{-17}\) \\  & & & & 0.0758 \\ \hline Geopolymer & 9.897 \(\times\) 10\({}^{-5}\) & 9.897 \(\times\) 10\({}^{5}\) & - & 6.33 \(\times\) 10\({}^{-17}\) \\  & & & & 0.0641 \\ \hline Mudstone (Carbon) & 2.330 \(\times\) 10\({}^{-7}\) & 2.330 \(\times\) 10\({}^{3}\) & - & 2.13 \(\times\) 10\({}^{-19}\) \\  & & & & 0.000216 \\ \hline Salt rock (Perman) & 4.815 \(\times\) 10\({}^{-7}\) & 4.815 \(\times\) 10\({}^{3}\) & - & 2.99 \(\times\) 10\({}^{-19}\) \\  & & & & 0.000303 \\ \hline Salt rock (Perman) & 1.95 \(\times\) 10\({}^{-11}\) & 0.195 & 1.586 \(\times\) 10\({}^{-12}\) & \begin{tabular}{c} 5.80 \(\times\) 10\({}^{-24}\) \\ 1 \(\times\) 10\({}^{-8}\) \\ \end{tabular} \\  & & & & \(1.62\times\) 10\({}^{-24}\) \\  & & & & \(1\times\) 10\({}^{-8}\) \\ \hline Epoxy resin & 1.820 \(\times\) 10\({}^{-11}\) & 0.182 & 1.479 \(\times\) 10\({}^{-12}\) & \begin{tabular}{c} 6.12 \(\times\) 10\({}^{-24}\) \\ 1 \(\times\) 10\({}^{-8}\) \\ \end{tabular} \\  & & & & \(1\times\) 10\({}^{-8}\) \\ \hline Epoxy resin & 2.350 \(\times\) 10\({}^{-11}\) & 0.235 & 1.907 \(\times\) 10\({}^{-12}\) & \begin{tabular}{c} 7.13 \(\times\) 10\({}^{-24}\) \\ 1 \(\times\) 10\({}^{-8}\) \\ \end{tabular} \\  & & & & \(1\times\) 10\({}^{-8}\) \\ \hline Epoxy resin & 3.220 \(\times\) 10\({}^{-11}\) & 0.322 & 2.637 \(\times\) 10\({}^{-12}\) & \begin{tabular}{c} 9.78 \(\times\) 10\({}^{-24}\) \\ 1 \(\times\) 10\({}^{-8}\) \\ \end{tabular} \\  & & & & \(1\times\) 10\({}^{-8}\) \\ \hline Epoxy resin & 1.770 \(\times\) 10\({}^{-11}\) & 0.177 & 1.436 \(\times\) 10\({}^{-12}\) & \
\begin{tabular}{c} 4.61 \(\times\) 10\({}^{-24}\) \\ 1 \(\times\) 10\({}^{-8}\) \\ \end{tabular} \\  & & & & \(4.61\times\) 10\({}^{-24}\) \\  & & & & \(1\times\) 10\({}^{-8}\) \\ \hline Epoxy resin & & & & \\ +fly ash (30\% vol.) & 1.774 \(\times\) 10\({}^{-11}\) & 0.177 & 1.411 \(\times\) 10\({}^{-12}\) &
\begin{tabular}{c} 5.24 \(\times\) 10\({}^{-24}\) \\ 1 \(\times\) 10\({}^{-8}\) \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Gas permeability of investigated samples. halloysite or graphite powder caused the increase of hydrogen permeability. An exception is the addition of fly ash. Admixture of 30% of volume gave a similar, but slightly lower permeability, comparing to the pure epoxy resin sample. Significant share of fly ash in sample composition did not cause the deterioration of sealing properties. Results were calculated for the steady-state diffusion. Usually, it took up to 3 weeks to achieve the steady-state diffusion. Increases in measured concentration of hydrogen per day of an example sample is presented in Figure 3. Because of the significant time required to complete the test for each sample, the hydrogen diffusion test was performed for a single gas pressure, which was 1.0 MPa. To verify the proper workings of the setup and sensitivity of the method, one test was extended and the feed gas pressure, after achieving steady-state diffusion, was increased. Pressure was increased after 24 days, from the value of 1.0 MPa to 1.7 MPa.