Applications of Instrumental Analysis and Chemometry to Old Roman Mortars and Stuccos

Small quantities of Roman mortars and stuccos from the Theatre of Marcellus and Porticus of Octavia were subjected to different instrumental techniques - thermogravimetric analysis (TG, DTG), Inductively Coupled Plasma Emission Spectroscopy (ICP-AES) and X-ray diffraction (XRD). The instrumental characterisation and chemometries allowed the stucco samples to be easily distinguished from the mortar. In practice, using the three instrumental analytical methods a total of 36 variables were obtained. The variables were then selected using PCA (Principal Component Analysis), reducing this number to 10. Lastly, using HCA (Hierarchical Cluster Analysis) a good separation was obtained between the two groups of samples (mortars and stuccos).