# Testing Concrete for the Construction of Winemaking Tanks
## 3 Results and Discussion
### Chemical Properties  
The results of the determination of the calcium hydroxide (Ca(OH)\({}_{2}\)) and calcium carbonate (CaCO\({}_{3}\)) contents are given in Table 7, as a percentage by weight (% \(w\)/\(w\)). The pH value of the concrete sample (measured on a dissolved in water sample with a glass electrode) is also given in Table 7. The measurements were conducted before the immersion of the specimens in wine. TG results show that the addition of pozzolan reduced the calcium hydroxide content (portlandite), while it bound calcium into calcium-silicate formations [29; 31]. Consequently, the addition of pozzolan succeeded in reducing portlandite content before 28 days and, thus, potentially reduces the calcium leaching or the interaction between portlandite and wine. The pH values of the samples were similar at the age of 28 days, showing that pozzolan addition did not modify the alkalinity of cement. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Composition**} & \multicolumn{2}{c}{**Dynamic Elastic**} & \multicolumn{2}{c}{**Compressive**} \\  & **Weight (g)** & \multicolumn{2}{c}{**Modulus (GPa)**} & \multicolumn{2}{c}{**Strength (MPa)**} \\  & **Before** & **After** & **Before** & **After** & **Before** & **After** \\ \hline C3 & 7.98 & 7.98 & 46.00 & 44.09 & 45.8 & 46.00 \\ CP10 & 7.81 & 7.81 & 44.75 & 44.47 & 42.7 & 46.25 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Thermal conductivity coefficient results. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Composition**} & \multicolumn{2}{c}{**\(\lambda\)**} & \multicolumn{2}{c}{**R**} \\  & **[W/(m \(\times\) K)]** & \multicolumn{2}{c}{**[(m\({}^{2}\)\(\times\) K)/W]**} \\  & **10 \({}^{\circ}\)C** & **20 \({}^{\circ}\)C** & **10 \({}^{\circ}\)C** & **20 \({}^{\circ}\)C** \\ \hline C3 & 1.2847 & 1.3753 & 0.0188 & 0.0173 \\ CP10 & 1.3972 & 1.5010 & 0.0211 & 0.0198 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Calcium hydroxide content, calcium carbonate and pH value in concrete samples of compositions C3 and CP10, at 28 days of age. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Composition**} & \multicolumn{2}{c}{**Weight (g)**} & \multicolumn{2}{c}{**Dynamic Elastic**} & \multicolumn{2}{c}{**Compressive**} \\  & **Before** & **After** & **Before** & **After** & **Before** & **After** \\ \hline C3 & 7.98 & 7.98 & 46.00 & 44.09 & 45.8 & 46.00 \\ CP10 & 7.81 & 7.81 & 44.75 & 44.47 & 42.7 & 46.25 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Results of experimental durability tests before and after the freeze-thaw cycling. The concrete specimens were removed from wine 30 days after part-immersion and the compressive strength of the specimens, the pH value and the calcium hydroxide content were determined. Additionally, ATR spectra were obtained from the surface material of the specimens to identify the clarity of the concrete structure. In Figure 3, the IR assignments of surface samples of immersed concrete specimens in red and white wine are displayed. The spectra show that wine did not interfere with the concrete structure, regardless of the presence of pozzolan in the concrete composition, or the type of wine that the specimens were immersed in. The concrete compositions' carbonates (1412 cm\({}^{-1}\), 871 cm\({}^{-1}\), 776 cm\({}^{-1}\)) and the CSH compounds (963 cm\({}^{-1}\)) did not present any modifications. The CSH peak intensity of CP10 and C3 samples in red wine was slightly lower compared to white wine (CP10L and C3L in Figure 3), although the difference is insignificant. The decrease in pH values after the immersion in wine (either white or red wine) is probably due to the wine quantity absorbed and/or remaining on the surface of the concrete (Table 8). It is also shown that the pH of CP10 is less resistant in wine immersion. The portlandite content of CP10 series was lower, compared to C3 series, due to the consumption of Ca(OH)\({}_{2}\) by the pozzolanic reaction. In Table 9, the Ca(OH)\({}_{2}\) % \(w/w\) content follows this trend.