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Use of poulticing in desalination of masonry units – implications on salt-deteriorated structures


Affiliations
1 Civil Engineering Discipline, Indian Institute of Technology Gandhinagar, Gujarat 382 355, India
2 Department of Civil Engineering, Indian Institute of Technology Madras, Chennai 600 036, India
 

Cellulose poulticing is a widespread method of desalination in practice for removal of salts from ancient structures. Optimization of the process is essential, considering that poulticing/desalination is the prime step during the protection of existing structures in the coastal zones. Even though poulticing is widely used in European countries, it is not common in India, because the principle and efficacy of the method have not been studied so far for masonry materials in the ancient Indian structures with specific microstructure. The present study analyses the effect of cellulose poulticing in bricks considering the role of pore size in the substrates and the removal of different types of salts depending upon the pore distribution. The process was found around 74% more efficient in removing Na2SO4 than NaCl in materials with more micropores (pore size <1 mm), as demonstrated from scanning electron microscopy images and analysis of pore structure using mercury intrusion porosimetry on brick samples. Interesting results on the unsuitability of cellulose poulticing in certain materials and the reasons for the same were obtained, which are based on the predominant transport mechanisms for salt removal. The study would be a reference for initiating cellulose poulticing as an effective desalination method in the ancient structures of coastal southern India

Keywords

Conservation, Desalination, Historic Structures, Protection, Salt Weathering.
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  • Flatt, R. J., Caruso, F., Sanchez, A. M. A. and Scherer, G. W., Chemo-mechanics of salt damage in stone. Nature Commun., 2014, 5, 1–5.

  • Scherer, G. W., Crystallization in pores. Cem. Concr. Res., 1999, 29, 1347–1358.

  • Flatt, R. J., Salt damage in porous materials: how high supersaturations are generated. J. Crystal Growth, 2002, 242(3–4), 435–454.

  • Vergès-Belmin, V. and Siedel, H., Desalination of masonries and monumental sculptures by poulticing: a review. Restor. Build. Monuments, 2005, 11(6), 391–408.

  • Weber, J., Insolubilisation of sulfate salts by baryum hydroxides: principles and experiences, insolubilisation des sulfates par leshydroxydes de baryum: principes et expérimentations, in Enduits dégradés par les sels: pathologies et traitements, Journée technique internationale, Paris 2004. Dossier technique ICOMOS-France 6, 2004.

  • Laue, S., Climate controlled behaviour of soluble salts in the crypt of St. Maria im Kapitol, Cologne. In Preservation and Restoration of Cultural Heritage LCP Congress, Montreux, 24–29 September 1995, Lausaunne, 1996, pp. 447–454.

  • Bollingtoft, P. and Larsen, K. P., The use of passive climate control to prevent salt decay in Danish churches, in Mauersalze und Architekturoberflächen, Tagungsbeiträge 2002 (eds Leitner, H., Laue, S. and Siedel, H.), Hochschule für Bildende Künste, Dresden, 2003, pp. 90–93.

  • Ranalli, G., Chiavarini, M., Guidetti, V., Marsala, F., Matteini, M., Zanardini and Sorlini, C., The use of microorganisms for the removal of nitrates and organic substances on artistic stoneworks. In Proceedings of the 8th International Congress on Deterioration and Conservation of Stone (ed. Riederer, J.), Berlin, Germany, 1996, pp. 1415–1420.

  • Rivas, T. E., Alvarez, E., Mosquera, M. J., Alejano, L. and Taboada, J., Crystallization modifiers applied in granite desalination: the role of the stone pore structure. Constr. Build. Mater., 2010, 24, 766–776.

  • Lisbeth, M., Ottosen, I. and Christensen, V., Electrokinetic desalination of sandstones for NaCl removal – test of different clay poultices at the electrodes. Electrochim. Acta, 2012, 86, 192–202.

  • Lubelli, B. and Hees, R. P. J., Desalination of masonry structures: fine tuning of pore size distribution of poultices to substrate properties. J. Cult. Herit., 2010, 11, 10–18.

  • Kumar, S. V. and Singh, M. R., Salt weathering of 7th century CE granite monument of Shore Temple, Mahabalipuram – scientific investigation and conservation strategy. Heritage, 2019, 2, 230– 253.

  • Benavente, D., García del Cura, M. A., García-Ginea, J., SánchezMoral, S. and Ordóñez, S., Role of pore structure in salt crystallization in unsaturated porous stone. J. Cryst. Growth, 2004, 260, 532–544.

  • Voronina, V., Salt extraction by poulticing: an NMR study. Ph D thesis, Eindhoven University of Technology, Lisbon, 2011.

  • Borrelli, E., Desalination systems: types, applications and efficacy. In Sais sol'veis em argamassas de edifìcios antigos: danos, processos e solúçoes: Lisboa, LNEC, 14 e 15 de Fevereiro de 2005. Laboratorio Nacional de Engenharia Civil, Lisbon, 2005.

  • Bowley M. J., Desalination of stone: a case study, Building Research Establishment, Garston, 1975, 46/75.

  • Lombardo, T. and Simon, S., Desalination by poulticing: laboratory study on controlling parameters. In Proceedings of the 10th International Congress on Deterioration and Conservation of Stone, Stockholm, Sweden, 2004, pp. 323–330.

  • Michálek, P., Tydlitát, V., Jerman, M. and Černý, R., Desalination of historical masonry using hydrophilic mineral wool boards. Comput. Methods Exp. Meas. XIII, WIT Transactions on Modelling and Simulation, 2007, vol. 46, pp. 377–385, ISSN 1743-355X.

  • Doehne, E., Schiro, M., Roby, T., Chiari, G., Lambousy, G. and Knight, H., Evaluation of poultice desalination process at Madame John’s Legacy, New Orleans. In Proceedings of the 11th International Congress on Deterioration and Conservation of Stone (eds Lukaszewicz, J. and Niemcewicz, P.), Nicolaus Copernicus University Press, Torun, Poland, 2008, pp. 857–864.

  • Blaeuer Boehm, C., Quantitative salt analysis in conservation of buildings. Restor. Build. Monuments: Int. J., 2005, 11(6), 409–418.

  • Manohar, S. and Santhanam, M., Salt crystallization in building materials in the marine environment. In Third R.N. Raikar Memorial International Conference and Gettu–Kodur International Symposium on Advances in Science and Technology of Concrete, American Concrete Institute – India Chapter, Mumbai, 2018.

  • Manohar, S., Santhanam, M. and Chockalingam, N., Performance and microstructure of bricks with protective coatings subjected to salt weathering. Constr. Build. Mater., 2019, 226, 94–105; https:// doi.org/10.1016/j.conbuildmat.2019.07.180.

  • Manohar, S., Bala, K., Santhanam, M. and Menon, A., Characteristics and deterioration mechanisms in coral stones used in a historical monument in a saline environment. Constr. Build. Mater., 2020, 241, 118102; ISSN 0950-0618.

  • Manohar, S. and Santhanam, M., Correlation between physical– mineralogical properties and weathering resistance using characterization case studies in historic Indian bricks. Int. J. Archit. Herit., 2020, doi:10.1080/15583058.2020.1833108.

  • Manohar, S., A study on characterization, deterioration mechanisms and protection of bricks and stones in historic structures, Ph D dissertation, Indian Institute of Technology Madras, Chennai, 2020.

  • Kröner, S., Alcaide, B. M. and Mas-Barberà, X., Influence of substrate pore size distribution, poultice type, and application technique on the desalination of medium-porous stones. Stud. Conserv., 2016, 61(5), 286–296; doi:10.1080/00393630.2015.1131942.

  • Sawdy, A., The role of environmental control for reducing the rate of salt damage in wall paintings. In Conserving the Painted Past: Developing Approaches to Wall Painting Conservation (eds Gowing, R. and Heritage, A.), James and James and English Heritage, London, UK, pp. 95–109.

  • Pel, L., Sawdy, A. and Voronina, V., Physical principles and efficiency of salt extraction by poulticing. J. Cult. Herit., 2010, 11, 59–67.


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  • Use of poulticing in desalination of masonry units – implications on salt-deteriorated structures

Abstract Views: 331  |  PDF Views: 124

Authors

Swathy Manohar
Civil Engineering Discipline, Indian Institute of Technology Gandhinagar, Gujarat 382 355, India
Manu Santhanam
Department of Civil Engineering, Indian Institute of Technology Madras, Chennai 600 036, India

Abstract


Cellulose poulticing is a widespread method of desalination in practice for removal of salts from ancient structures. Optimization of the process is essential, considering that poulticing/desalination is the prime step during the protection of existing structures in the coastal zones. Even though poulticing is widely used in European countries, it is not common in India, because the principle and efficacy of the method have not been studied so far for masonry materials in the ancient Indian structures with specific microstructure. The present study analyses the effect of cellulose poulticing in bricks considering the role of pore size in the substrates and the removal of different types of salts depending upon the pore distribution. The process was found around 74% more efficient in removing Na2SO4 than NaCl in materials with more micropores (pore size <1 mm), as demonstrated from scanning electron microscopy images and analysis of pore structure using mercury intrusion porosimetry on brick samples. Interesting results on the unsuitability of cellulose poulticing in certain materials and the reasons for the same were obtained, which are based on the predominant transport mechanisms for salt removal. The study would be a reference for initiating cellulose poulticing as an effective desalination method in the ancient structures of coastal southern India

Keywords


Conservation, Desalination, Historic Structures, Protection, Salt Weathering.

References





DOI: https://doi.org/10.18520/cs%2Fv121%2Fi10%2F1307-1315