Multitechnique approach for unveiling the technological evolution in building materials during the Roman Imperial Age: The Atrium Vestae in Rome

.The present study focuses on the chemical characterisation of the bricks and mortars of a Roman Imperial building, the Atrium Vestae, characterised at least by five building phases. From each phase, brick and mortar samples were selected in order to emphasise compositional differences and/or possible evolutions in the materials employed and in the building technology of different historical periods. This investigation is carried out by a multitechnique approach based on: optical microscopy (OM), X-ray diffraction (XRD), Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM-EDS), Fourier Transform InfraRed (FT-IR) and micro-Raman spectroscopies. The comparison between contemporary samples or between samples produced in different ages provided important information to be integrated with the archaeological and historical data highlighting an improvement in the technological skill during the Imperial time. Furthermore, compositional similarities between samples of controversial dating, offered a hint to discriminate certain building phases and, finally, the compositional analyses were also extremely useful to determine the condition of the entire building.