Monument Future - Siegfried Siegesmund

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with feature repaired).

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      Figure 4: a. Splintering, chipping, paint film, perforation and perforation with metallic insert in pilaster of Andes Street, b. Splintering with development of two parallel fractures.

      Figure 5: Soiling in inner faces of Plaza Independencia columns: a. Partially “washed out”, b. Rock without deterioration beneath partially eroded soiling.

      Features induced by material loss is the second most represented family, being rounding, perforation and missing part the ones which affect the higher number of pilasters and columns. Many perforations present metallic inserts, which causes very frequently oxide staining leading eventually to bursting (Figure 3). In the steps, rounding affects almost all pieces, abrasion and missing part a quarter of them.

      The most represented family is Discolouration and deposit. Six subtypes of deposits are very frequently observed (dust deposit, paint, stick, cement, grease and pigeon droppings) in pilasters, columns and steps. Patina is frequent in small areas of the pieces. Soiling is very frequent in inner areas of pilasters and columns of the Gallery and Plaza Independencia, sheltered from rain and wind (Figures 5 and 6).

      A deterioration association is observed in two felsic enclaves up to 40 cm in two faces of a highly exposed column of Plaza Independencia. The association includes bleaching, pitting, blistering, spalling and differential erosion, and is more advanced in the enclave which is frequently exposed to dog urine. This association is presumably related to the action of SO2 product of air pollution, that causes feldspar kaolinsation and possible salt formation, as described by Schiavon (2007). Family Biological colonization is only represented by very seldom spider nets.

      Other alterations are modification of the original basement ventilation elements, in Andes Street, 18 de Julio Avenue and Gallery. Most of them were transformed to access steps to business, which originally had no exterior access. These steps are made up of other rocks (Pan de Azúcar Syenite due to the similarity in décor) or monolithic (Table 5). Other category is “Strange elements”, including commercial posters, door numbers, etc.

      A map of a column of Plaza Independencia is presented in figure 6. View I faces Plaza Independencia and is exposed, and View III faces the Gallery and is sheltered from rain and wind.

      Figure 6: Deterioration map of Column 6 of Plaza Independencia (modified from FADU, 2019).

       112Discussion and recommendations

      There were no conservation programs developed in Palacio Salvo. Only minor reparations can be observed. In this study it is strongly recommended the design and implementation of a conservation program. Alternative nonaggressive measures are proposed if this program can not be developed.

      Cracks related to splintering and chipping should be studied in detail to determine their cause. In general, cracks, fractures (with or without fragmentation), can be consolidated and mechanically repaired after cleaning and removal of loose fragments (Matero & Tagle, 1995). As consolidant Siegesmund & Snethlage (2011) recommend TEOS. For the repair of cuts, perforation, gaps and missing parts it is recommended to prepare patches of different colors, textures and materials, that can replicate the décor of Kösseine Granite, including the different enclaves observed. The metallic inserts should be removed by gentle mechanical means or by using a drill of small diameter to prevent damaging the rock around it.

      Deposits weakly attached and spider nets should be removed by mechanical means (soft brush, plastic spatula). Soiling and deposits strongly attached could be removed by steam jet, as described in Siegesmund & Snethlage (2011). Oxide staining could be mobilized by chemical complexing or sequestering agents that can be soaked up or flushed away (Matero & Tagle, 1995). Following these authors, poultices with different chemical compounds could be used to remove oxide staining, grafitti, paint films, and eventually deposits of cement, and others that could not be removed by the previous methods.

       Conclusions

      The present study is the first documented case of a deterioration assessment of a dimensional stone façade in Uruguay performed by a geological team. The rock applied is identified as Kösseine Granite, of Wunsiedel, Germany.

      No conservation program was developed prior to this study in Palacio Salvo, although minor reparations have been recognized. Using ICOMOS (2011) deterioration glossary, five deterioration families were recognized, being Features induced by material loss and Discoloration and deposit the most represented. Of the first family rounding, perforation (with and without metallic insert), and missing part are the most frequent, both in pilasters, columns and steps, being abrasion very frequent in the latter. They are all related with anthropogenic activities and not a consequence of poor rock quality. Of the second family, the most frequent deteriorations are deposits and soiling.

      Other relevant alterations are replacement of original pieces in steps, mostly by monolithic and Pan de Azúcar Syenite, that matches the décor of Kösseine Granite. The good performance of Kösseine Granite in Palacio Salvo after 92 years of exposure is related to its excellent physical and mechanical properties.

       References

      IC-FADU (Instituto de Construcción, Facultad de Arquitectura, Diseño y Urbanismo) (2019) Propuesta de intervención para la conservación de las fachadas del Palacio Salvo.

      Grimm WD (2018) Bildatlas wichtiger Denkmalgesteine der Bundesrepublik Deutschland. Ebner Verlag GmbH & Co.

      Matero FG, Tagle AA (1995) Cleaning, Iron Stain Removal, and Surface Repair of Architectural Marble and Crystalline Limestone: The Metropolitan Club. J. Am. Inst. Conserv. Vol.34 I.1.

      Morales Demarco M (2012) Mineralogical, Petrophysical and Economical Characterization of the Dimensional Stones of Uruguay; Implications for Deposit Exploration. Diss Univ Göttingen.

      Mosch S (2008) Optimierung der Exploration, Gewinnung und Materialcharakterisierung von Naturwerksteinen. Diss Univ Göttingen.

      Oyhantçabal P (2005) The Sierra Ballena Shear zone: kinematics, timing and its significance for the geotectonic evolution of southeast Uruguay. Diss Univ Göttingen.

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       2000 YEARS OF USE OF PLASTER AS BUILDING AND RESTORATION MATERIAL FOR THE „TAKHT-E SOLEYMAN“ IN WESTERN AZERBAIJAN, IRAN

      IN: SIEGESMUND, S. & MIDDENDORF, B. (EDS.): MONUMENT FUTURE: DECAY AND CONSERVATION OF STONE.

       – PROCEEDINGS OF THE 14TH INTERNATIONAL CONGRESS ON THE DETERIORATION AND CONSERVATION OF STONE –

       VOLUME I AND VOLUME II. MITTELDEUTSCHER VERLAG 2020.