Statistical analysis on ancient mortars: A case study of the Balivi Tower in Aosta (Italy)

This study proposes a first approach to the characterization of the composition and degradation products of historical mortars and their classification through chemometric analysis. This work also aimed at comparing the usefulness and applicability of analytical techniques that are commonly used for mortar examination. Calcimetry, Thermogravimetric Analysis (TGA) and Differential Thermal Analysis (DTA), Ionic Chromatography (IC) and Fourier Transform Infrared Spectroscopy (FT-IR) were used to analyse a number of samples collected from the quadrangular Tower of the Balivi Complex in Aosta (Italy). Cluster Analysis and Principal Components Analysis (PCA) were carried out on the analytical results, and the accordance and the relevance of the results were evaluated. The role of the variables on the samples description and their correlation were evaluated. The results showed the division of the samples into groups that were probably due to the presence of different mortar types manufactured in different periods. Furthermore, an irregular degradation pattern on the four facades and at different heights of the tower was highlighted.