Cit:Dreyfuss.etal:2018
| Autor | Dreyfuss, T.; Cassar, J. |
| Jahr | 2018 |
| Titel | Consolidating porous limestone: from the laboratory to the field |
| Bibtex | |
| DOI | https://doi.org/10.5165/hawk-hhg/432 |
| Link | https://www.hornemann-institut.de/de/epubl_download.php?epid=196&et=1&tbid=&eamail= |
| Bemerkungen | in: KONSOLIDIEREN UND KOMMUNIZIEREN Materialien und Methoden zur Konsolidierung von Kunst- und Kulturgut im interdisziplinären Dialog: Tagungsband der internationalen Tagung der HAWK Hochschule für angewandte Wissenschaft und Kunst in Hildesheim vom 25.–27. Januar 2018 anlässlich des 30jährigen Jubiläums der Restaurierungsstudiengänge |
Eintrag in der Bibliographie
| [Dreyfuss.etal:2018] | Dreyfuss, T.; Cassar, J. (2018): Consolidating porous limestone: from the laboratory to the field. In: Tagungsband der internationalen Tagung der HAWK Hochschule für angewandte Wissenschaft und Kunst in Hildesheim vom 25.–27. Januar 2018 anlässlich des 30jährigen Jubiläums der Restaurierungsstudiengänge (Hrsg.): KONSOLIDIEREN UND KOMMUNIZIEREN Materialien und Methoden zur Konsolidierung von Kunst- und Kulturgut im interdisziplinären Dialog,Michael Imhof Verlag 80-91, Webadresse. |  |
Abstract[Bearbeiten]
The consolidation of a soft porous limestone, often heavily contaminated with soluble salts, and generally found making up the architectural and archaeological fabric in the Mediterranean, is being discussed here, in particular ammonium oxalate treatment. This treatment was chosen following positive results published in the literature and extended local research. The lack of suitable consolidating treatments for porous stone in such environments, as well as possible interactions of the proposed treatment with the naturally occurring soluble salts on site, initiated this research programme. The long-term study, which was structured into three independent but interrelated phases, aimed at investigating such possible interactions, one variable at a time, in the laboratory, and led to an understanding of the complex interactions on site. Soft and porous limestone is particularly susceptible to salt deterioration; one typical example of this is the Maltese Globigerina Limestone, a highly porous limestone which is representative of others present in the Mediterranean (other similar examples include Pietra di Lecce and Pietra di Noto). This limestone from Malta was used throughout this research. Three soluble salt types were identified as being the most representative of a Mediterranean scenario, these being chlorides, sulfates and nitrates. In Phase 1, previously desalinated quarry samples were artificially contaminated with individual chloride, sulfate and nitrate salts of sodium, treated with ammonium oxalate and tested, under controlled laboratory conditions. This study then progressed to Phase 2, where a parallel set of salt-contaminated samples, identical to those studied in Phase 1, were introduced to external inland, urban conditions, treated on site, allowed to weather naturally for 1 year and then similarly tested in situ. In the third and final phase, naturally weathered stone on a wall in the same urban environment, forming part of a historical building, was characterized, treated and tested on site. In all cases, treatment was applied using a 5% ammonium oxalate monohydrate poultice, as established in the early 1980s. The testing, on untreated and treated stone, was designed to evaluate aesthetic changes through colorimetry, depths of calcium oxalate formation and physical properties of newly formed calcium oxalate through Drilling Resistance Measurement System (DRMS) and the tape test as well as the water transport properties through the contact sponge method. Treatment resulted in an aesthetic improvement, surface consolidation was verified, while adequate water transport properties in the liquid phase were retained. The depth of whewellite formed, which ranged from 0.7 mm to 1.6 mm, was found to be related to the presence of soluble salts during treatment. Results were considered to be very positive and also brought out further areas of research that merit investigation for the continued development of in situ conservation of salt-contaminated porous limestone, which could be applicable to similar stones in the Mediterranean. This will however need to be preceded by even further research, especially in situ.