La vicenda dei restauri della basilica Giulia al Foro Romano. Riflessioni sulle miscele pozzolaniche per la conservazione

This paper deals with the investigation of the main historical events and archeological exacavations of Basilica Giulia (Roman Forum, Rome). The construction of Basilica Giulia probably began in 54 b.C., under Julius Caesar’s command, but it was subjected to different interventions due to natural and anthropic causes during the following centuries. In 1803, during Pio VII pontificate, the archeological excavation of Forum area was started, but only in 1848 L. Canina found the first traces of the Basilica, then totally brought to light in 1870 by P. Rosa. The residual structures of basilica Giulia, excavated by G. Maetzke in 1988, showed materials, in particular pozzolanic mortars, with a different degree of alteration. Mortars were analyzed in order to archieve specific informations about their elemental and mineralogical composition. Mortar identification, indeed, is a fundamental step in the design of repair products, taking into account the necessary compatibility between original materials and new ones. In this context, Vitruvious’ indications were discussed and mechanical tests on pozzolanic mortar samples, reproduced in laboratory, were carried out. The study of mortar manufacture provides useful information on building culture, eventually helping in setting conservative interventions.