## 4 Tests Results and Discussion
They should be also considered in relation to average value of \(V_{S}\) for each method. Excluding zero crossing method, for pure RCA specimens' standard errors are from 0.2% to 0.4% of the average value of \(V_{S}\), and for RCA with rubber \begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline \hline  & & & \multicolumn{6}{c}{**RCA with Rubber Chips No. 4**} \\ \cline{3-13}  & & **Period (ms)** & 0.10 & 0.12 & 0.14 & 0.16 & 0.18 & 0.20 & 0.22 & 0.24 & 0.26 & 0.28 \\ \cline{2-13}  & **Peak-to-peak\_1** & & 103.3 & 103.1 & 102.0 & 101.4 & 100.9 & 100.3 & 100.0 & 99.6 & 99.4 & 98.6 \\ \cline{2-13}  & **Peak-to-peak\_2** & & 103.2 & 103.5 & 102.3 & 101.1 & 102.4 & 100.5 & 100.4 & 99.7 & 99.5 & 98.5 \\ \cline{2-13}  & **Zero crossing** & 240.0 & 251.4 & 159.2 & 160.6 & 112.9 & 111.5 & 111.2 & 109.7 & 108.8 & 107.9 \\ \cline{2-13}  & **Cross correlation** & 135.5 & 93.4 & 94.2 & 94.9 & 95.1 & 95.3 & 95.3 & 95.5 & 95.4 & 95.4 \\ \cline{2-13}  & **Frequency domain** & 95.1 & 101.3 & 185.5 & 118.8 & 137.9 & 111.2 & 113.9 & 129.1 & 111.5 & 112.8 \\ \hline \multicolumn{13}{c}{**RCA with Rubber Chips No. 5**} \\ \cline{3-13}  & **Period (ms)** & 0.10 & 0.11 & 0.12 & 0.13 & 0.14 & 0.15 & 0.16 & 0.17 & 0.18 & - \\ \cline{2-13}  & **Peak-to-peak\_1** & & 113.5 & 112.5 & 111.8 & 111.1 & 110.8 & 110.1 & 110.4 & 110.6 & 110.6 & - \\ \cline{2-13}  & **Peak-to-peak\_2** & & 114.1 & 113.0 & 112.4 & 111.5 & 110.9 & 109.9 & 109.8 & 110.0 & 110.7 & - \\ \cline{2-13}  & **Zero crossing** & 265.4 & 184.6 & 266.0 & 125.6 & 124.9 & 124.3 & 123.6 & 122.8 & 122.8 & - \\ \cline{2-13}  & **Cross correlation** & 370.3 & 103.2 & 63.8 & 104.8 & 105.0 & 105.3 & 105.3 & 105.3 & 105.1 & - \\ \cline{2-13}  & **Frequency domain** & 363.8 & 312.3 & 128.3 & 286.3 & 125.7 & 129.4 & 130.6 & 131.9 & 132.8 & - \\ \cline{2-13}  & **Period (ms)** & 0.10 & 0.12 & 0.14 & 0.16 & 0.18 & 0.20 & 0.22 & 0.24 & 0.26 & 0.28 \\ \cline{2-13}  & **Peak-to-peak\_1** & & 150.2 & 150.0 & 149.8 & 149.1 & 147.9 & 147.3 & 146.5 & 145.6 & 144.9 & 143.7 \\ \cline{2-13}  & **Peak-to-peak\_2** & & 150.1 & 149.7 & 150.8 & 150.1 & 148.1 & 147.5 & 145.7 & 145.5 & 145.5 & 144.2 \\ \cline{2-13}  & **Zero crossing** & 184.4 & 204.5 & 218.4 & 349.4 & 561.9 & 271.8 & 158.4 & 156.4 & 155.7 & 155.7 \\ \cline{2-13}  & **Cross correlation** & 143.6 & 142.9 & 142.5 & 141.7 & 141.6 & 141.2 & 141.0 & 140.6 & 140.3 & 140.1 \\ \cline{2-13}  & **Frequency domain** & 173.3 & 147.9 & 149.1 & 147.9 & 144.0 & 143.2 & 142.9 & 143.0 & 143.2 & 142.7 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Shear wave velocity (\(V_{S}\)) of mixtures of RCA with rubber chips by four different methods of interpretation and three different mean effective stresses. chips from 0.4% to 3.3%. This actually confirms the small values of errors as well as the accuracy of the interpretation methods chosen. \begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline  & \multicolumn{1}{c}{} & \multicolumn{1}{c  
An analysis of uncertainty was also required, in order to approve the precision and credibility of this study. Relative uncertainty in the range of 0.1% to 10% is typical for laboratory experiments. Based on data summarized in Tables 5 and 6, it can be seen, that uncertainty of the results is at the level of 1-2% (specimens No. 1-3) and of 1.4%-30% (specimens No. 4-6), where the highest value was obtained for specimen No. 5. It is clear, that the time domain methods allow for very accurate measurement of \(V_{S}\), the lowest uncertainty of the results. In Table 7, selected statistical parameters, i.e., dispersion, standard deviation and standard error, from all four methods together for each specimen are summarized. Pure RCA specimens are characterized by lower values of these parameters (from 50% to 90%), especially specimen No. 2, tested at \(p^{\prime}\) = 90 kPa, than three mixtures of RCA with rubber chips. In the case of composite, No. 5, tested as well at \(p^{\prime}\) = 90 kPa, the values of dispersion, standard deviation and error are the highest.