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| Natura: | Artículo científico |
| Lingua: | en |
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Academia Brasileira de Ciências
2006
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| Accesso online: | https://www.redalyc.org/articulo.oa?id=32778211 |
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Sommario:
- Surface modification of a granite building stone in central Rio de Janeiro Fabio S. Castanheira Maria Augusta M. Silva José Antônio Baptista-Neto Bernard J. Smith John J. McAllister Multidisciplinaria (Ciencias Naturales y Exactas) granite weathering air pollution gypsum crusts marine aerosols In order to evaluate environmental controls on the soiling formation and decay of building stones a set ofmapping and physical and chemical analyses were carried out on granite from a historical church in thepolluted centre of Rio de Janeiro. These techniques highlight the increasing of threatening damage ongenerally perceived as a durable building material, caused by granular disaggregation and contour scalingin areas close to ground level. Mapping also indicated the formation of black crusts over entire buildingfaçades, concentrated on areas sheltered from rain-wash. Analyses demonstrated the influence of marineaerosols, rock and mortar composition and mostly of the atmospheric pollutants on the decay and soilingof the granite. Much of the decay is associated specifically with the presence of halite (NaCl) and gypsum(CaS04.2H2O). The fact that black, gypsum crusts are able to develop over entire façades in a humid subtropicalenvironment is testimony to the high levels of local pollution, especially particulate deposition.Reduced rainwash, in sheltered micro-environments of narrow, canyon-like streets, overcomes the gypsumtendency to bewashed away from buildings façades. These observations further highlight that decay processesare primarily controlled by microclimatic conditions. 2006 artículo científico 0001-3765 https://www.redalyc.org/articulo.oa?id=32778211 en http://www.redalyc.org/revista.oa?id=327 Anais da Academia Brasileira de Ciências application/pdf Academia Brasileira de Ciências Anais da Academia Brasileira de Ciências (Brasil) Num.2 Vol.78