# Marble and Glass Waste Powder in Cement Mortar
## 3 Results and Discussion
### Microstructure Properties of Hardened Mortar
#### 4.3.4 FT-IR  
Figure 15 illustrates the IR spectra of mortar pastes containing MGWP as a partial replacement alongside the control mix. The spectra reveal peaks at 443, 462, and 465 cm\({}^{-1}\), corresponding to the Si-O-Si bond bending/vibrations typically associated with C\({}_{2}\)S. Similarly, peaks at 870, 867, and 873 cm\({}^{-1}\) are attributed to C\({}_{3}\)S for 0%, 10%, and 30% MGWP mixes, respectively, at 7 days of curing [68]. The incorporation of 10% MGWP exhibits a broader and more intense absorption band at 958, 962, and 960 cm\({}^{-1}\) for the control, MGWP10, and MGWP30 mixes, respectively. This peak is associated with hydrated silica  
Figure 14: TGA and DTA analysis of mortar specimens containing MGWP at curing ages of 28 days. \begin{table}
\begin{tabular}{l c c c c} \hline \hline
**Initial Mass Taken = 10 mg** & \multicolumn{4}{c}{**Mass Loss**} \\ \hline \multirow{2}{*}{**Mix Code**} & \multicolumn{2}{c}{**At 7 days**} & \multicolumn{2}{c}{**At 28 days**} \\ \cline{2-5}  & **(mg)** & **(\%)** & **(mg)** & **(\%)** \\ \hline MGWP0 & 1.185 & 11.85 & 1.151 & 11.51 \\ MGWP10 & 0.981 & 9.81 & 0.895 & 8.95 \\ MGWP30 & 1.766 & 17.66 & 0.945 & 9.45 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Summary of mass loss from TGA analysis at various thermal events, corresponding to Figures 13 and 14.  
phases (Si-O-T (T: tetrahedral Si or Al) asymmetric stretching vibration). The enhanced intensity at 10% MGWP aligns well with the improvements observed in compressive strength, UPV, and SEM analyses. Notably, the formation of C-S-H gel typically manifests within the wavenumber range of 900-1100 cm\({}^{-1}\)[69; 70]. Water absorption is evident at 1622 cm\({}^{-1}\), within the characteristic range of 1600-1700 cm\({}^{-1}\), due to H-O-H bending vibrations. As shown in Figure 15, the bandwidth at 10% MGWP is narrower compared to both the control and 30% MGWP mixes. This suggests that at 10% MGWP, a greater proportion of water is consumed in hydration reactions, facilitating C-S-H gel formation and enhancing the microstructural properties of the mortar [70]. Similarly, O-H stretching of water appears within the range of 3000-3700 cm\({}^{-1}\) at 3432 cm\({}^{-1}\)[71; 72]. The O-H stretching bond of Ca(OH)\({}_{2}\) is observed around 3663 cm\({}^{-1}\). The C-O asymmetric stretching bond of CO\({}_{3}\)\({}^{-}\), indicative of atmospheric carbonation, appears at 1414 cm\({}^{-1}\), within the range of 1300-1700 cm\({}^{-1}\)[72]. The lower intensity of Portlandite in the 10% MGWP mix compared to the control suggests that more Ca(OH)\({}_{2}\) is utilized in the formation of C-S-H gel as the hydration reaction progresses [69]. Additionally, the asymmetric stretching vibrations of the sulfate group (SO\({}_{4}\)\({}^{2-}\)) in gypsum at 1104 cm\({}^{-1}\) are replaced by a new band at approximately 1116 cm\({}^{-1}\), corresponding to SO\({}_{4}\)\({}^{2-}\) vibrations in Ettringite. Furthermore, the C-H stretching bond of CH\({}_{2}\) appears at 2928 cm\({}^{-1}\)[70]. Figure 16 illustrates the FT-IR spectra of MGWP-containing mortar after 28 days of curing. A pronounced improvement in C-S-H gel formation is observed at 10% MGWP replacement compared to 7-day spectra. The primary C-S-H bands appear at 980, 985, and 1033 cm\({}^{-1}\) for the control, MGWP10, and MGWP30 mixes, respectively. The broader and more intense C-S-H peaks at 10% MGWP at 28 days suggest enhanced pozzolanic reactivity, resulting in greater gel formation. The O-H bending and stretching bonds of H\({}_{2}\)O are detected at approximately 1606 cm\({}^{-1}\) and 3362 cm\({}^{-1}\), respectively. Portlandite (Ca(OH)\({}_{2}\) remains present at around 3698 cm\({}^{-1}\), while calcite (CaCO\({}_{3}\)) appears at approximately 1426 cm\({}^{-1}\). Peaks associated with C\({}_{2}\)S and C\({}_{3}\)S persist at 443, 463, and 458 cm\({}^{-1}\) and at 870, 865, and 869 cm\({}^{-1}\), respectively, indicating ongoing hydration.