Contribution of thermal analysis in the characterization of lime-based mortars with oxblood addition

In this study, thermogravimetry and differential scanning calorimetry (TG-DSC) along with X-ray diffraction analysis (XRD) and Fourier transform infrared (FTIR) spectroscopy in attenuated total reflectance (ATR) mode, were performed on a series of lime mortar specimens with oxblood addition. Calculated TG weight loss showed that at initial stages, oxblood addition could slow down the carbonation process. Specimens containing oxblood showed two peaks above similar to 550 degrees C in their DSC curves, and the combination of TG-DSC and ATR techniques allowed to speculate that the first peak (at lower temperatures) could correspond to the decomposition of CaCO3 at a lower degree of crystallinity (e.g. amorphous calcium carbonate (ACC), aragonite, vaterite), while the second peak (at higher temperatures) corresponded to the decomposition of calcite. Additionally, XRD and ATR results indicated that ACC was formed in the specimens containing oxblood at a first stage, and as time progresses, ACC could transform to vaterite and then to calcite.