Geopolymers as potential repair material in tiles conservation
- 339 Downloads
The restoration materials currently used to fill gaps in historical architectural tiles (e.g. lime or organic resin pastes) usually show serious drawbacks in terms of compatibility, effectiveness or durability. The existing solutions do not fully protect Portuguese faïence tiles (azulejos) in outdoor conditions and frequently result in further deterioration. Geopolymers can be a potential solution for tile lacunae infill, given the chemical–mineralogical similitude to the ceramic body, and also the durability and versatile range of physical properties that can be obtained through the manipulation of their formulation and curing conditions. This work presents and discusses the viability of the use of geopolymeric pastes to fill lacunae in tiles or to act as “cold” cast ceramic tile surrogates reproducing missing tile fragments. The formulation of geopolymers, namely the type of activators, the alumino-silicate source, the quantity of water required for adequate workability and curing conditions, was studied. The need for post-curing desalination was also considered envisaging their application in the restoration of outdoor historical architectural tiles frequently exposed to adverse environmental conditions. The possible advantages and disadvantages of the use of geopolymers in the conservation of tiles are also discussed. The results obtained reveal that geopolymers pastes are a promising material for the restoration of tiles, when compared to other solutions currently in use.
KeywordsPore Size Distribution Geopolymer Fume Silica Soluble Salt Ceramic Substrate
The authors acknowledge Fundação para a Ciência e a Tecnologia for financial support for the development of the present research (Project CerAzul: PTDC/CTM-CER/119085/2010 and UID/EAT/00729/2013). Cromogenia Units from Spain is thanked for providing Metastar® 501, and Nova Terracota S.A. from Portugal for the ceramic biscuits used. Norman H. Tennent and Isabel Martins are acknowledged for the discussion and advice during the work.
- 13.A. Pinto, Sistemas Ligantes Obtidos por Activação Alcalina do Metacaulino. Ph.D. thesis, Minho University (2004)Google Scholar
- 19.M. Mendes, T.A. Ferreira, J.D. Rodrigues, J.M. Mimoso, S.R.M. Pereira, Volumetric and chromatic reintegration in conservation of in situ glazed tiles. in International Conference, Glaze Ceramics in Architectural Heritage (LNEC, Lisbon, Portugal, 2015), pp 259–261Google Scholar
- 24.©Imerys Minerals Ltd. 2012. Europe. http://www.imerys-perfmins.com/eu/markets/building-construction.htm. Accessed 10 Oct 2014
- 26.©Imerys Pigments. 2010 North America http://www.imerys-perfmins.com/usa/ProductDetail.asp?PID=425. Accessed 10 October 2014
- 27.J. Musacch, Conservation of historical Portuguese tiles: adhesives for outdoor exposure. Master’s Thesis (2012)Google Scholar
- 35.J. Costa Pessoa, J.F. Farinha Antunes, M.O. Figueiredo, M.A. Fortes, Stud. Conserv. 41(3), 153–160 (1996). http://www.jstor.org/stable/10.2307/1506530
- 37.J.L.F. Antunes, D.S. Tavares, in dE la Cerámica Decorada estudio y la Conservación dE la Cerámica Decorada En Arquitectura, ed. by A. Balderrama, A. Vidal, I. Cardiel, E.N. Roma (ICCROM, Roma, 2003), p. 22Google Scholar
- 38.M.T. Mendes, S. Pereira, T. Ferreira, J. Mirão, A. Candeias, Int. J. Cons. Sci. 6(1), 51–62 (2015)Google Scholar
- 45.C.A. Rees, J.S.J. van Deventer, J. Provis, G.C. Lukey, Mechanisms and kinetics of gel formation in geopolymers, PhD thesis, The University of Melbourne (2007). http://hdl.handle.net/11343/39579
- 46.S. Pereira, J.M Mimoso, A. Santos Silva, Physical-Chemical characterization of historic portuguese tiles, Relatório 23/2011-NPC/NMM, LNEC (2011)Google Scholar