# Testing Concrete for the Construction of Winemaking Tanks
## 3 Results and Discussion
### Chemical Properties
Lower pH values and lower portlandite contents are attributed to the same influence factor as with the coefficient of resistance in water vapor permeability results, which is the interaction of portlandite with pozzolan. Furthermore, portlandite content increased after the immersion of the concrete cubes in wine. As the concrete cubes remained in wine for 30 days the cement hydration evolution led to the formation of additional portlandite. The latter is a piece of evidence that immersion in wine did not hinder the cement hydration in time. Accordingly, the decrease in pH value cannot be connected to the deterioration of the concrete samples but could only be connected to the decrease of calcium hydroxide content. The mineralogical composition of the samples before and after immersion did not present significant differences, which supports the stability of the C3 and CP10 in wine (Figure 4). The identified crystalline phases were common to all samples. The dominant mineralogical phase of the samples was quartz, originating from silica sand. Crystalline phases are found in lower proportions: albite, albite, microcline, phlogopite, portlandite and calcite. Albite, anorthite and orthoclase are sodium and potassium aluminosilicate phases due to the presence of silica sand. Portlandite found before immersion was derived from the hydration of clinker. Chlorite and magnesium silicate peaks in the C3_K sample are impurities of the silica sand. Tables 9 and 10 display the concentration of metals in mg/L or  
Figure 3: ATR spectra of tested concretes C3 and CP10 after immersion in white (L) and red (K) wine. \(\mu\)g/L in the samples of white and red wine, after concrete immersion for 30 days. The determination of metals in the wine revealed the presence and the absence of specific metals in mg/L and \(\mu\)g/L. Mercury and lead were completely absent. Selenium and cadmium, along with chromium and copper, were found in very small amounts in white wine. Potassium and magnesium were found in significant amounts, compared to the other metals. The values of the plain white wine were considered as the values to compare with the affected wine, after the immersion of coating of coated concrete specimens and uncoated concrete. The three tested coatings and coating-free samples behaved differently in the wine environment, within 30 days of influence. Coating D presented the optimum results, compared to the other systems. More precisely, the pH values and the content of the metals in the white wine after the immersion of concrete with D coating remained approximately stable. Wine is an acidic solution for concrete. As a result, this coating protected concrete from wine influence, as well as it protected the white wine from concrete leaching. Coatings A and S presented similar behaviour. The metals that had the greatest leaching from coating to white wine were calcium, sodium and nickel. Ferron, arsenite and cobalt were found to increase after immersion and very small modifications of the concentration were detected for chromium, copper, potassium, magnesium and manganese. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Composition** & **Immersion in Wine** & **pH** & **Ca(OH)2** \\  & & & **\% _w/w_** \\ \hline C3 & - & 13.08 & 9.24 \\ CP10 & - & 12.96 & 4.85 \\ C3\_K & Red & 11.76 & 11.71 \\ CP10\_K & Red & 9.80 & 8.30 \\ C3\_L & White & 10.92 & 11.63 \\ CP10\_L & White & 9.14 & 7.79 \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Values of pH and calcium hydroxide content on the surface of concrete samples before and after immersion in wine.