Mortars from the Roman villa of the Vetti (Tuscany): preliminary data

Since the end of the III century A.D. the Roman Empire lived a period of relative stability and the following decades knew a sort of villas renaissance, especially in the peripheral areas. The Roman villa of the Vetti (middle IV century), built in the town of Limite sull’Arno (Florence), is one of the most interesting late ancient aristocratic mansion discovered in the present Tuscany, comparable to other examples like those of San Vincenzino (Livorno) and Torraccia di Chiusi (Siena). The archaeological excavations have revealed a portion of the pars urbana and in particular an apsidal room and its mosaic floor in which a hunting scene is pictured (Alderighi et al., 2011). This work is focused on plasters and mortars found in this sector of the building during the campaigns of 2010 and 2011. From the macroscopic point of view (number of layers, aggregate/binder ratio, colour of binder) four different types of plaster mortars have been identified; a fifth group comprehends the mortars from joints between masonry units and from the mosaic pavement. Mineralogical and petrographic data obtained by optical observation and XRPD, TG/DSC analyses as suggested by Riccardi et al. (2007) indicate the presence into mortars of hydraulic binders and river sand as aggregate fraction. Some plaster fragments are characterized by the presence of decorative painting; petrographic features, XRPD and SEM data suggest the use of lime milk (white), ochers (red, yellow, brown and orange), carbons (black) and the typical egyptian blue pigment.