Use of stone and construction technologies in the medieval and modern fortifications of Cagliari (south-Sardinia, Italy)

The work deals the relationship between the building technologies employed since the XVI centuries and the use of stone in the construction of Cagliari boundary walls. These fortifications shows the designs of "modern" technologies that around the middle of the XV century in Europe replaced the medieval walls. This evolution entailed several changes to the structures including: lowering of buildings, replacement of quadrangular medieval towers with the same number of lesser height cylindrical, which had the function of better resist to the hits and reduce the disastrous effects of the collapses. Then, increase the thickness of the walls through the creation of embankments. To better understand the use of stone in the works of the Cagliari a mapping of the various lithologies was made to petrographic classification of the materials. Secondly, it has been determined the physical-mechanical properties of identified lithologies to verify, from one side, the chemical-physical decay state and, on the other side, the correctness of their technical choice in different parts of wall structure.