Deterioration of the granitic stones of main front of the Vila Real Cathedral (N of Portugal)
DOI:
https://doi.org/10.3989/mc.2009.40307Keywords:
Vila Real cathedral, granite, alteration, deterioration, soluble salts, haliteAbstract
The cathedral of Vila Real (North of Portugal) is located in the city centre and at least four regional two-mica granites were used in its construction. A petrographic study of these granites concluded that the stones had different degrees of alterations. The identification of some physical properties of the granites –open porosity, real and apparent density, free water absorption, porometry and capillary transmission– confirms their susceptibility to degrees of weathering. A recent cleaning intervention was made and several types of deterioration were visible in the monument‚s stones, namely: granular disintegration, some thin black layers, plates, flakes and black crusts, especially in the main front exposed to SW. Granular disintegration is the most important deterioration process and is responsible for the loss of material in the most-affected stones; it is also related to the presence of small amounts of highly soluble salts such as halite and nitrates and to solar exposure.
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(1) Matos, V.: “A geologia da região de Vila Real”. Tese de Doutoramento, Universidade de Trás-os-Montes e Alto Douro, Vila Real (1991), p. 312.
(2) Peixoto, J. C. C.; Pinho, M. M.; Vinagre, P. J. S.: “Monitorização da qualidade do ar em Vila Real”. Relatorio no publicado, Universidade de Trás-os-Montes e Alto Douro, Vila Real (2004), p. 42.
(3) Norma UNE-EN 1936: “Determinación de la densidad real y aparente y de la porosidad aberta y total”. AENOR, Madrid (1999).
(4) Norma UNE-EN 1925: “Absorción de agua por Capilaridad”. AENOR, Madrid (1999).
(5) Norma ICR 7/81: “Absorção de água por imersão total – capacidade de embebição”. ICR - Instituto Central de Restauro (1981).
(6) Schiavon, N.: “Kaolinisation of granite in an urban environment”. Env. Geol., vol. 52 (2007), pp. 399-407. doi:10.1007/s00254-006-0473-0
(7) Ordaz, J.; Pérez-Ortiz A.; Esbert R. M.; Martínez-Nistal, A.; Alonso, F. J.: “Study of the granite crack network by means of digital image processing”. Proceedings of the EC Workshop on Degradation and conservation of granitic rocks in monuments. Protection and Conservation of European Cultural Heritage, Research Report nº5, 1996, pp. 249-254.
(8) Begonha, A.: “Meteorização do granito e deterioração da pedra em monumentos e edifícios da cidade do Porto”. Tese de Doutoramento, Universidade do Minho, Braga (2001), p. 393.
(9) Rivas Brea, T.; Prieto Lamas, B.; Silva Hermo, B.: “Ensayos de alteración artificial aplicados a rocas graníticas”. Mater. Construcc., vol. 58, n. 289-290 (2008), pp. 179-189. doi:10.3989/mc.2008.v58.i289-290.80
(10) Aires-Barros, L.: “As rochas dos monumentos portugueses, tipologias e patologias”. Instituto Português do Património Arquitectónico. Ministério da Cultura, Lisboa, volume I (2001), p. 335.
(11) Sousa, L. M. O.: “Estudo da fracturação e das características físico-mecânicas de granitos da região de Trás-os-Montes com vista à sua utilização como rocha ornamental”. Tese de Doutoramento. Universidade de Trás-os-Montes e Alto Douro. Vila Real (2000<), p. 358.
(12) Benavente, D.; Cueto, N.; Martínez-Martínez, J.; García del Cura, M. A; Cañaveras, J. C.: “The influence of petrophysical properties on the salt weathering of porous building rocks”. Env. Geol., vol. 52 (2007), pp. 215-224. doi:10.1007/s00254-006-0475-y
(13) Esbert, R. M.; Ordaz, J., Alonso, F. J.; Montoto, M.; González Limón, T.; Ballester, M. A. B.: “Manual de diagnosis y tratamiento de materiales pétreos y cerámicos”. Collegi.d`Aparelladors i Arquitectes Tècnics de Barcelona, Barcelona (1997), p. 139.
(14) Montoto, M.: “Petrophysics at the rock matrix scale: hydraulic properties and petrographic interpretation”. Publicaciones técnicas Enresa (2003), p. 291.
(15) Steiger, M.: “Crystal growth in porous materials - II: influence of crystal size on the crystallization pressure”. J Cryst Growth, vol. 282 (2005), pp. 470-481. doi:10.1016/j.jcrysgro.2005.05.008
(16) Gómez-Heras, M.; Fort, R.: “Patterns of halite (NaCl) crystallisation in building stone conditioned by laboratory heating regimes”. Env. Geol., vol. 52 (2007), pp. 259-267. doi:10.1007/s00254-006-0538-0
(17) Gómez-Heras, M.; Benavente, D.; Buergo, M. A., Fort, R.: “Soluble salts minerals from pigeon droppings as potential contributors to the decay of stone based Cultural Heritage”. Eur. J. Min. 16 (2004), pp. 505-509. doi:10.1127/0935-1221/2004/0016-0505
(18) Angeli, M.; Bigas, J.; Benavente, D.; Menéndez, B.; Hébert, R.; David, C.: “Salt crystallization in pores: quantification and estimation of damage“. Env. Geol., vol. 52 (2007), pp. 205-213. doi:10.1007/s00254-006-0474-z
(19) Silva, B.; Rivas, T.; Prieto, B.; Auger, F.: “Soluble Salts in Granitic Monuments: Origin and Decay Effects”. In: Applied Study of Cultural Heritage and Clays (2003), pp. 113-131.
(20) Charole, A. E.; Pühringer, J.; Steiger, M.: “Gypsum: a review of its role in the deterioration of building materials”. Env. Geol., vol. 52 (2007), pp. 339-352. doi:10.1007/s00254-006-0566-9
(21) Alonso, F. J.; Vázquez, P.; Esbert, R. M.; Ordaz, J.: “Durabilidad de granitos ornamentales: valoración de los daños inducidos por el ensayo de cristalización de sales”. Mater. Construcc., vol. 58, n. 289-290 (2008), pp. 191-201. doi:10.3989/mc.2008.v58.i289-290.78
(22) Silva, B.; Rivas, T.; García-Rodeja Prieto, B.: “Distribution of ions of marine origin in Galicia (NW Spain) as a function of distance from the sea”. Atmospheric Environment, 41 (2007), pp. 4396-4407. doi:10.1016/j.atmosenv.2007.01.045
(23) Grossi, C.: “Cristalización de sales en rocas monumentales porosas y su auscultación mediante emisión acústica”. Tesis Doctoral. Departamento de Geología, Universidad de Oviedo (España) (1992), p. 261.
(24) Smith, B. J.; Warke, P. A.; McGreevy, J. P.; Kane, H. L.: “Salt-weathering simulations under hot desert conditions: agents of enlightenment or perpetuators of preconceptions?”. Geomorph., 67 (2005), pp. 211–227. doi:10.1016/j.geomorph.2004.03.015
(25) López-Arce, P.; Doehne, E.; Martin, W., Pinchin, S.: “Sales de sulfato magnésico y materiales de edificios históricos: simulación experimental de laminaciones en calizas mediante ciclos de humedad relativa y cristalización de sales”. Mater. Construcc., vol. 58, n. 289-290 (2008), pp. 125-142.doi:10.3989/mc.2008.v58.i289-290.77
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