Traditional masonry techniques and characterization of materials: the Mezzaspiaggia tower (Cagliari, Sardinia)

Object of the study are some towers situated in the geographical area of Cagliari, belonging to the Sardinia coast defense system realized between the 16th and the beginning of the 17th century. This architectural organization, very rich and articulated, is full of historical and cultural significance, being the expression of traditional human activities. Even so, it is actually in a progressive state of degradation, having lost, since 19th century, a role in our society. Starting by this preamble, i.e. with the purpose of warranting a better preservation and management of similar cultural heritage examples, the contribution illustrates the results of a deep analysis concerning the above mentioned structures, investigated following an interdisciplinary approach. The research has been carried out integrating historical-archaeometrical and scientific methodologies. Specifically, by one side, the constructions have been explored by an architectural point of view, using a methodology based on the chrono-typological analysis of masonries, showing their structural aspects and the executive modalities for their setting up. All that, through metric and photographic surveys, supported by drawings highlighting the constructive peculiarities of the masonries analyzed. By the other side, they have been studied by mineralogical-petrographic and geochemical methods (XRD, EPMA) for the characterization of stony elements, the analysis of plasters and mortars, arriving to define their main features, and trying to identify the provenance area of materials. The principal objectives of this research are: 1. the individuation of peculiarities distinguishing traditional building techniques during this period observed; 2. the knowledge of constructions and of their phenomena and degradation causes, to warranty, in the restoration project phase, appropriate interventions; 3. to facilitate, on the basis of acquired data, the dating of other contemporary edifices, especially referring to the so-called ‘minor’ building, very often object of inconvenient interventions, with great detriment for their conservation, just for its non-identification