Venice: Stone Material Behaviour in Connection with the Environment
- PDF / 4,898,103 Bytes
- 11 Pages / 420.48 x 639 pts Page_size
- 75 Downloads / 179 Views
VENICE: STONE MATERIAL BEHAVIOUR IN CONNECTION WITH THE ENVIRONMENT G. BISCONTIN°,
V. FASSINA*,
P. MIARAVELAKI**,
E. ZENDRI°
Dipartimento di Scienze Ambientali - Universita di Venezia, Italy *) Laboratorio Scientifico della Soprintendenza ai Beni Artistici e Storici di Venezia, Italy **) Scholarship holder of the State Scholarships Foundation of Greece, Greece 0)
ABSTRACT The present study is directed to summarize several studies carried out in the recent past on stone decay processes taking place in the lagoon environment of Venice. The behaviour of the main types of stones used in Venetian buildings has been considered. Istrian stone, Verona red stone and Carrara marble were studied. The knowledge of the porosity and of the pore size distribution can contribute to clarify the physical transformation of decayed materials. The research determined the morphology of stone decay processes for the different types of stone. As far as the morphology of deterioration is concerned, there are two main types of decay which depend on the intrinsic properties of the stone: chemical-mineralogical composition and texture-structure.
INTRODUCTION The behaviour of stone in Venice is strongly dependent on the environment. The vicinity of the sea and the presence of the lagoon create extremely unfavourable environmental conditions to the conservation of works of art.
In the past, stone materials for building construction were chosen by rigorous criteria, based on previous experiences and always in relation to the environment in which they were placed. Since ancient times, the main negative parameter was well known to be salt water which acts directly as a corrosive agent or indirectly as a marine aerosols carrier (M). From this consideration the choice of Istrian stone for manifold purposes, as architectural, decorative or structural element, is a natural consequence.
In fact, since the beginning, Istrian stone revealed a strong resistance to weathering agents especially in an aggressive marine environment like that of Venice. The use of other types of stone in big buildings in most cases was extremely unsuccessful. One of the most significant examples of failure was the use of Carrara marble on the facade of the "Scalzi Church", near the railway station. Since the beginning, the architect was sharply exposed to censure for the inappropriate choice of the stone material and his scarce knowledge of the Venetian environment (2). In these last decades, an acceleration of stone disease was observed in correspondence with the increasing rate of air pollution due to the Mat. Res. Soc. Symp. Proc. Vol. 185. ,1991 Materials Research Society
254
industrialization and the Mestre respectively (3).
urbanization taking
place in Porto
Marghera and
Comparison of the decay of Venetian monuments with that of other more polluted towns, shows that the phenomenon in Venice is more emphasized. In fact, the role of air pollution is enhanced by the unfavourable marine environment. ATMOSPHERIC POLLUTION Since the beginning of the seventies, s
Data Loading...
