Ancient Mortars Technology: Archaeometric Study of Mortars from Ex Cinema Astra Site in Verona

The city of Verona in the Roman Age was one of the most important cities in Northern Italy. The city's growth was evident in its unique structures, showing exceptional construction techniques and enduring quality, particularly in its mortar production. The varied techniques in mortar production were influenced by factors like available materials, scale of construction, and historical/geographical considerations. Understanding these processes offers insights into construction methods, including material quality, technical expertise, and overall construction significance, helping to understand the past to preserve in the future. The Ex Cinema Astra, dated from the 1930’s, was abandoned for over 20 years, and rediscovered due to archaeological traces found during a 2004-2005 in a foundation inspection. Excavations resumed in 2021 and revealed a large Roman complex dating from the 1st to 3rd century AD, marking one of the most significant archaeological finds in Verona in recent decades. This study was carried out in order to identify the ruins mortar's composition in different locations, which were attributed to different construction or conservation periods and reports the results of the analysis of mortars used in the archaeological site discovered beneath the Cinema. The characterization of the samples provided information on the raw materials used in the mixtures, the production technology of mortars, and the building phases. The characterization methodology involved an archaeometrical study aimed at the microstructural characterization of the mortars, particularly through petrographic analysis and scanning electron microscopy (SEM) for the identification of the mortar's constituents as well as in the evaluation of the state of conservation. The results of the analysis have been compared to offer valuable information into the employed production methods, the components of the recipes, and the resulting characteristics of the mortars.