Characterization of Roman and medieval mortars from the Pisa’s Cathedral Square (Italy)

The study of ancient mortars plays an important role in the interpretation of an archaeological site and gives interesting information about construction technologies and building materials used in ancient times. The present work focused on the study of mortars used in the construction of some Roman buildings and of the old Pisa’s Cathedral in the Miracles Square (Italy). This area, included since 1987 in the World Heritage List of the UNESCO, is famous for the presence of an important historical complex built in the middle Ages (the Cathedral, the Baptistery, the Campanile and the Monumental Cemetery). The archaeologists discovered some structures related to more ancient periods: the Roman domus (1st – 5th centuries) and the older cathedral with its foundations and crypt (10th century). The aim of this work is to characterize the mortars from Roman and medieval structures of the above-quoted buildings, with a particular interest in determining the provenance of the raw materials and the technologies used in a same district, but in different periods. Forty-two samples were collected from both the structures of the old Pisa’s cathedral and the Roman buildings. Based on minero-petrographic, XRF, XRPD, TG-DSC and SEM-EDS analyses the main characteristics of binder and aggregate of the mortars have been determined and some raw materials used for the production of the analysed binding materials have been identified.