The Influence of the Climatic Factors on the Decay of Marbles: an Experimental Study

Stone decay is affected by the influence of climatic factors. In particular marble degradation, that could be expressed by decohesion and /or bowing, is mainly due to the action of temperature and water (rains and relative humidity). In this work non destructive and destructive tests have been performed to evaluate the decay of marble slabs subjected both to natural exposition and to artificial ageing tests (Lab - Bow test). Measurements of Ultrasonic Pulse Velocities (UPV) and bowing have been executed periodically on marble slabs exposed for a period of four years as preliminary field tests. On the base of this work an integrated test methodology to monitoring and previewing the behaviour of façade slabs have been set up. The methodology has been applied on the marble façade of modern building of centre Italy and consists of in situ and laboratory tests. In laboratory a destructive test (flexural strength) has been added to the non destructive tests to evaluate the decay before and after cycles of an ageing test. The results of the analysis, show an evaluative trend of the decay, though it changes its slope after 25 cycles of the ageing test. Moreover this work confirms the effectiveness of the employed non destructive tests and their god correlation with the mechanical tests.