Assessment of Pentelic Marble Surfaces After Ammonium Oxalate Protective Treatments
The artificial oxalate method has been thoroughly studied over the last decades as a compatible and performing protective treatment for marbles and other calcite stones. In this study, the most widely used synthesis (5% w/v ammonium oxalate aqueous solution) was applied by brushing on pentelic marble surfaces and assessed in terms of surface texture alterations. Three differently textured marble surfaces were produced in terms of roughness levels, and were measured by a mechanical roughness meter. Scanning Electron Microscopy (SEM) proved to be an indispensable tool in order to investigate the morphological alterations of the process through the comparison of the original surface texture with the one induced by the conversion of calcite into calcium oxalate. The calcium oxalate formation was verified by Raman spectroscopy, where whewellite was clearly detected. Finally, the digital imaging processing of the SEM images served as an indicative tool for the quantification of the process, regarding the surface percentage that is covered by the newly formed calcium oxalate.
KeywordsRaman SEM Calcium oxalate Protection Stone Pentelic marble
The authors declare that no funding was received, while performing the research presented in this paper. This research was performed at the National Technical University of Athens (NTUA) and it is part of the Master Thesis of G. Frantzi, who is employed by the Acropolis Restoration Service (YSMA).
The authors declare that there is no conflict of interest regarding the publication of this paper.
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- 10.Matteini, M.: Inorganic treatments for the consolidation and protection of stone artefacts. Conserv. sci. cult. herit. 8(1), 13–27 (2008)Google Scholar
- 12.Polykreti, K., Maniatis, Y., Doganis, Y., Galanos, A., Valavanis, P.: Analysis of the orange-brown patina on marble surfaces from the Olympieion in comparison with a similar patina from the Propylaea, Acropolis. In: Fakorellis, Y., Zacharias, N., Polykreti, K. (eds.) Proceedings of the 4th Symposium of the Hellenic Society for Archaeometry, BAR International Series, Athens, vol. 1746, pp. 659–666 (2008)Google Scholar
- 18.Abràmoff, M.D., Magalhães, P.J., Ram, S.J.: Image processing with ImageJ. Biophoton. Int. 11(7), 36–42 (2004)Google Scholar
- 19.EN 15886: Conservation of cultural property – Test methods – Color measurement of surfaces (2010)Google Scholar
- 25.Alexakis, E., Delegou, E.T., Lampropoulos, K.C., Apostolopoulou, M., Ntoutsi, I., Moropoulou, A.: NDT as a monitoring tool of the works progress and the assessment of materials and rehabilitation interventions at the Holy Aedicule of the Holy Sepulchre. Constr. Build. Mater. 189, 512–526 (2018)CrossRefGoogle Scholar