Archeometrical Analysis for the Characterization of Mortars from Ostia Antica

The aim of the study is to provide, through the characterization of the mortar samples and the relative raw materials, useful information in order to define the stages of construction, the workers technological and archaeological knowledge. The study is an interdisciplinary approach carried out by different analysis techniques in order to define the mineral-petrographic composition and highlight the differences among the various samples. Mortars are present in all the walls, except dry ones, as a bedding material and as a coating. The mortars may be regarded as markers for excellence, because they must be prepared at the time of their use, during the construction of the masonry, and cannot be re-used after their hardening and socket. Furthermore, the production of mortars in the past depended on the availability of raw materials in situ thus establishing a strong and direct correlation between the origin and use.The chemical and petrographic study of the subtle differences and composition of the mortar makes it possible to use this material as an excellent timeline if the supply of building materials varies over time. Mortars, for these reasons, play two key roles in archaeological survey: an absolutely priority for the correct determination of the contours of Stratigraphic Units; the role of the typological class very representative and very useful for making comparisons between different parts of the building and connecting between them the activities of the individual site.