## 3 Results and Discussion
### Physicochemical Characterization  
The analysis of the XRD patterns of the WBA and AA-WBA binders shows the presence of new crystalline phases. The appearance of new peaks or variations demonstrates the formation of new crystalline phases in the AA-WBA binders. This can be observed in the shaded areas of Figure 4, where the XRD pattern of WBA compared with that of the AA-WBA-6M sample is shown. \begin{table}
\begin{tabular}{c c c} \hline \hline  & **Mass Dissolved by SAM (wt.\%)** & **Mass Dissolved by HCl (wt.\%)** \\ \hline Portland cement paste & 89.8 & - \\ WBA powder & 15.9 & - \\ AA-WBA-2M & 16.6 & 56.0 \\ AA-WBA-4M & 24.2 & 57.6 \\ AA-WBA-6M & 33.5 & 59.9 \\ AA-WBA-8M & 29.7 & 61.5 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Salicylic acid/methanol (SAM) and HCl extraction results. Figure 4: XRD patterns of WBA and AA-WBA-6M. In the shaded areas of Figure 5a,b, some variation on the peaks' intensity between the AA-WBA binders is appreciated, therefore indicating that the amount of these new crystalline phases increases as the NaOH concentration increases. Figure 6a,b depicts the XRD patterns of AA-WBA-6M and AA-WBA-8M samples, respectively. These two formulations contain the highest percentage of C-(A)-S-H phases as demonstrated above (see Section 3.2). In both cases, the main reaction products formed are calcium silicate hydrate (C-S-H; PDF# 003-0728), gehlenite (Ca2 Al2 SiO? ; PDF# 01-072-2128), and reinhardtiinature (Ca5(SiO4)2(OH)2; PDF# 029-0380). In the AA-WBA-8M sample, gismondine (CaAl2 Si2O8.4H2O; PDF# 020-0452) and gaylussite ((Na2 Ca(CO3)2:5H2O; PDF# 020-1088) were also identified. All the aforementioned compounds are related with C-(A)-S-H phases excluding gaylussite, which is a sodium carbonate compound that reveals the cation exchange between precursor and alkali-activator solution [51]. It is important to note that XRD results agree with the results obtained in the selective chemical extractions. Depicted in Figure 7 is the WBA FTIR spectrum compared to the FTIR spectra of the AA-WBA binders, which was used to find evidence of the alkali-activation of the WBA. The broad band at 984 cm\({}^{-1}\) ascribed to T-O stretching vibrations (where T=Si or Al) was displaced towards higher frequencies, indicating the formation of C-(A)-S-H gel [52]. With respect to the AA-WBA spectra, a shift of the main broad band towards lower frequencies was observed. This fact is probably due to both the inclusion of aluminum on the C-S-H gel [53], which is consistent with chemical extraction  
Figure 5: XRD patterns of (**a**) AA-WBA-2M and AA-WBA-4M, and (**b**) AA-WBA-6M and AA-WBA-8M. Figure 6: XRD patterns of (**a**) AA-WBA-6M and (**b**) AA-WBA-8M. and XRD results. There was a weak peak at 780 cm\({}^{-1}\) associated with Si-O-Si bridging bonds in quartz (SiO\({}_{2}\)) [54]. The peak mentioned above was indiscernible in AA-WBA-6M and AA-WBA-8M samples. This fact probably means that a large proportion of quartz had reacted to form new phases due to the higher alkalinity of the alkali-activator solution used. The strong band at 1429 cm\({}^{-1}\), assigned to the stretching mode of carbonates, as well as sharp peaks at 875 cm\({}^{-1}\) and 713 cm\({}^{-1}\) which were related to the bending mode of carbonates, were less intense in AA-WBA binders [54]. The FTIR spectra of WBA before and after SAM is shown in Figure 8a. The band at 984 cm\({}^{-1}\) associated with T-O stretching vibrations (where T=Si or Al) was shifted to 1003 cm\({}^{-1}\), which means that C-(A)-S-H phases were dissolved by SAM extraction [55]. The strong band at 1429 cm\({}^{-1}\), assigned to the stretching mode of carbonates, as well as sharp peaks at 875 cm\({}^{-1}\) and 713 cm\({}^{-1}\) related to the bending mode of carbonates, did not present any changes. Figure 8b shows the FTIR spectra of the AA-WBA-6M sample before and after SAM and HCl extraction. This sample was chosen because it was the one that would potentially present better results.