POZZOLANIC CEMENTUM OF THE ANCIENT CONSTRUCTIONS IN 'CAMPI FLEGREI' AREA

摘要

In the research program concerning the heritage in the Campania region, particular attention is paid to ancient constructions of the Campi Flegrei (burning fields), which are subject to eruptive phenomena and frequent bradyseism cycles. At the beginning of the 3rd century BC, the cementum technique (concrete) had already marked a revolutionary development in construction method. The breakthrough was the discovery that a volcanic powder — pozzo-lana - mixed in suitable proportions with lime created a mixture that also set under river and seawater with excellent qualities of resistance and durability. This article focuses on pozzo-lanic concrete and its interaction with the other materials — tuff, bricks, trachyte — used in foundations, wharfs, water reservoirs. In addition, examples of buildings for which such materials were used are described in detail. Moreover, the present study considers the results of mechanical characterization of some mortars and the evaluation of the compressive strength of several specimens at the different setting times. Finally, a few hints are proposed for a correct strengthening.