Assessment of limestone deterioration due to salt formation by micro-Raman spectroscopy: application to architectural heritage

Author(s)
Sabina Kramar, Maja Urosevic, Helmut Pristacz, Breda Mirtic
Abstract

Salt crystallisation is a principal deterioration factor of many stonemonuments. In this study, samples of weathering productsof two baroque monuments in Ljubljana, Slovenia (the Fountain of Three Carniolian Rivers and the side altar of the Church ofSt. James), as well as the limestone used in their construction (Lesno Brdo limestone)were investigated in order to ascertain themain mineral phases produced during theweathering process. A combination of micro-Raman spectroscopy and X-ray powderdiffractionwas successfully applied to identifymicrometre-size minor components in the limestone and theweathering productphases. In addition to calcite and dolomite as the main components of the Lesno Brdo limestone, quartz, anatase, goethite,haematite and phyllosilicates were also determined as minor limestone minerals. The limestone was found to be extensivelydeteriorated in both outdoor and indoor environments in the studied historical monuments, showing flaking, subflorescence,efflorescences, crumbling and black and white crusts as a result of the deterioration phenomena. Among these weatheringforms, efflorescences were found to be more complex in terms of mineral assemblage, where gypsum was associated tohexahydrite, pentahydrite, and nitre. In contrast to the efflorescences, the mineralogy of subflorescences as well as that ofwhite and black crust from outdoor and indoor conditions was rather simple, composed of only gypsum. The results showedthat gypsum also crystallised under the surface as subflorescence, which eventually led to the flaking and crumbling of thelimestone.

Organisation(s)
Department of Mineralogy and Crystallography
External organisation(s)
University of Ljubljana, Universidad de Granada
Journal
Journal of Raman Spectroscopy
Volume
41
Pages
1441-1448
No. of pages
8
ISSN
0377-0486
DOI
https://doi.org/10.1002/jrs.2700
Publication date
11-2010
Peer reviewed
Yes
Austrian Fields of Science 2012
1030 Physics, Astronomy, 105116 Mineralogy, 201203 Architectural theory
Portal url
https://ucrisportal.univie.ac.at/en/publications/61d2ebe7-d8e0-45a8-92b5-4a4cc2c43f43