## 3 Results and Discussion
### XRD and FT-IR Analysis
The largest ones are concentrated in G3-14 and G3-28, and are up to 50% more intense than those in group G1, which can be attributed to a greater development of crystallinity in its phases [41], mainly due to a greater reactivity of the FA, because of the increase of the specific surface area induced by the reduction of particle size by grinding, which causes the weakening of Si-O and Al-O bonds and thus promotes the incorporation of soluble Si and Al in the crystalline chain. The band at 3437 cm\({}^{-1}\) is derived from the O-H stretching present in the FA. In the same way, this band appears wider in the geopolymeric samples due to the overlapping of signals, originating from the contribution of hydroxyl systems of the alkaline activator to the chemical structure of G1, G2, and G3. On the other hand, the free water present in the FA shows a low transmittance at 1630 cm\({}^{-1}\). This is attributed to the low contained humidity; however, in G1, G2, and G3 a more intense band appeared at 1655 cm\({}^{-1}\) due to the presence of physically bound water (H-O-H), which was produced by the hydrolysis that occurs from the specific equilibrium process of aluminates and silicates until the final polymerization of the geopolymer. Figure 4: FT-IR spectra of FA-1 and obtained geopolymers at different curing days. The intensification of the band at 1428 cm\({}^{-1}\) is attributed to the C-O bonds present in NaCO\({}_{3}\) (Figure 3c) produced by the reaction of free NaOH in the geopolymers with CO\({}_{2}\) from the environment. At 1092 cm\({}^{-1}\), a band corresponding to the FA-1 spectrum is observed and there is a shift towards lower wavenumber, in the 1000 and 1016 cm\({}^{-1}\) range, attributed to the asymmetric stretching of the Si-O-Si and Al-O-Si bonds present in the semicrystalline gel of the specimens. The presence of this band is considered the most important, since it provides information related to the development and polymerization of the alkali-activated FA [23; 38; 42]. Spectra deconvolutions were performed (Figures 6-8) which show these shifts of the evolution of the bands that characterize these activated materials. The assignment of bands is proposed in Table 3.  
Figure 5: Intensities ratio of faujasite and type Y-zeolite phases obtained by X-ray diffraction. Figure 6: FT-IR deconvolution spectra in the range of 1350–850 cm\({}^{-1}\) (geopolymers at 7 curing days). The spectra deconvolution allows us to observe the shift and the displacement of the bands of FA-1 towards lower wavenumbers with more precision, as well as to establish the changes that occur in the material during polymerization and ascertain with greater certainty that the FA was activated and a geopolymer is obtained. In the spectra analyzed by this method, it can be seen that the curing time is a factor that determines the process, but that the particle size from the first days of curing influences the polymerization process to a greater extent through the activation of the FA. The width of the blue band is wide because of the diversity of vibrations Si-O and Al-O produced by the amorphous molecule of the reaction product [44,45]. Figure 8: FT-IR deconvolution spectra in the range of 1350–850 cm\({}^{-1}\) (geopolymers at 28 curing days). Figure 7: FT-IR deconvolution spectra in the range of 1350–850 cm\({}^{-1}\) (geopolymers at 14 curing days). \begin{table}
\begin{tabular}{c|c} \hline
**Band (cm\({}^{-1}\))** & **Color** & **Assignment** \\ \hline
1230–1250 & Asymmetric stretching (Si-O-Si and Al-O-Si) \\
1150–1200 & Asymmetric stretching (Si-O-Si) \\
1050–1150 & Asymmetric stretching of amorphous phase (Si-O-Si and Al-O-Si) \\
980–1030 & Asymmetric stretching of N-A-S-H gel (Si-O-Si and Al-O-Si) \\ \hline \end{tabular}
\end{table} 
Table 3: Characteristic IR vibrational bands of geopolymers [43].