Advanced Materials Research Vol. 897 (2014) pp 305-308 Online available since 2014/Feb/19 at www.scientific.net © (2014) Trans Tech Publications, Switzerland doi:10.4028/www.scientific.net/AMR.897.305
Analysis of Building Stone of the Medieval Historical Building BALINTOVA Magdalena1,a*, ESTOKOVA Adriana1,b, SICAKOVA Alena1,c , HOLUB Marian1,d and SINGOVSZKA Eva1,e 1
Technical University of Kosice, Faculty of Civil Engineering, Institute of Environmnetal Engineering, Vysokoskolska 4, 042 00 Kosice, Slovakia a
[email protected], badriana.
[email protected],
[email protected], d
[email protected],
[email protected]
Keywords: building stone, XRF, XRD, FTIR
Abstract. The reconstruction of the historical buildings needs the replacement of the original and damaged materials using possible compatible materials that closely replicates the original ones in its appearance, chemical, physical and mineralogical properties, strength and durability. Thus, a complex approach based on advanced analytical methods is needed to identifying of the suitable materials. The paper is aimed at the study of the chemical and mineralogical properties of the historical stones of the medieval castle in the East Slovakia in order to replacement the original materials by the new ones with similar composition. The carbonates and silicates were confirmed as the main components of the stones by X – ray fluorescence (XRF) and Fourier transformation infrared (FTIR) methods. The mineralogical analysis confirmed the presence of the calcite as the dominated carbonate minerals as well as the presence of the quartz and muscovite representing the silicate forms. Introduction Castles and manor houses form a significant part of the Slovak historical heritage. The process of preserving and reconstructing historical buildings poses several specific questions and raises problems which must be solved in the planning and management stage of the building process. When the reconstruction of the historical buildings needs the replacement of the original and damaged stones, possible compatible materials closely replicating the original in its appearance, chemical, physical and mineralogical properties, strength and durability should be used[1, 2]. Thus testing of the original stones of the monument is required due to the selection of new stones with appropriate and compatible characters [3, 4]. In accordance with [1], the selection process involves several steps: After establishing the historical and physical significance of the building and the likely impact of any proposed intervention follow assessing and understanding weathering and other decay processes affecting the stone. The next steps involve the undertaking an initial fabric/masonry survey to determine the need for stone replacement; defining the types of stone used, by visual examination in situ and answering any technical questions in steps mentioned above, by using the most appropriate analytical techniques on samples taken from the site. The following step is samples obtaining of potential replacement stone, and testing these where necessary together with sourcing and securing replacement stone from existing quarries or (in certain cases) from quarries temporarily re-opened for the purpose. Examination and analysis of stone should involve petrographic analysis, physical-chemical parameters and other parameters. Criteria for selecting replacement stone involve mainly petrography, chemical characteristics, appearance, geological age, porosity and compressive strength. [5]. For example although petrographic analysis is always the first step to characterize the rock structure, it is difficult to achieve a quantitative characterization of mineral phases of some stones and therefore the using of XRD method can be helpful [6]. This paper is aimed at the study of the building stone of medieval historical castle in terms of its chemical and mineralogical composition by application of advanced methods for identification of stones used in individual parts of structure. All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of TTP, www.ttp.net. (ID: 147.232.17.72-13/03/14,09:53:41)
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Material and Methods Eighteen stone samples were taken from three damaged objects of the medieval castle. The samples were air dried, crushed, homogenized and pulverized by using planetary ball mill SFM (MTI corp., USA). Chemical composition of tested stone samples was investigated by X-ray fluorescence analysis (XRF) using SPECTRO iQ II (Ametek, Germany) with SDD silicon drift detector with resolution of 145 eV at 10 000 pulses. Infrared spectroscopy with Fourier transformation (FTIR) was used for the stone samples characterization in terms of functional groups qualitative analysis. FTIR measurements were performed using a Spectrometer Alpha-T (Bruker, Germany) with ATR technique in transmittance mode, in the range 400 – 4000 cm-1 with resolution of 4 cm-1. The crystalline structure of stones was identified with diffractometer Bruker D2 Phaser (Bruker AXS, GmbH, Germany) in Bragg-Brentano geometry (configuration Theta-2Theta). Results and discussion The results of the chemical analysis of the stone samples by XRF method are presented in Table 1. The percentage of the basic components is expressed in form of oxides. Table 1. The results of the chemical analysis of stone samples by XRF. Object
I
II
III
Sample I/1 I/2 I/3 I/4 I/5 II/1 II/2 II/3 III/1 III/2 III/3 III/4 III/5 III/6 III/7 III/8 III/9 III/10
CaO (%) 67.54 57.90 0.99 5.31 0.53 22.2 0.47 50.95 51.48 43.36 66.70 61.49 48.75 31.91 50.18 51.97 56.04 44.49
SiO2 (%) 1.41 2.14 82.99 80.45 87.26 48.90 81.21 0.32 3.28 0.89 4.85 1.58 0.67 0.48 7.43 0.72 0.84 1.56
Al2O3 (%) 0.47 0.79 7.18 1.21 6.81 8.63 10.81 0.12 1.18 0.44 1.59 0.79 0.26 0.21 1.70 0.32 0.39 0.55
Fe2O3 (%) 0.18 0.23 6.18 3.47 3.37 7.09 3.94 0.11 0.48 0.14 0.59 0.24 0.11 0.06 0.65 0.08 0.11 0.11
MgO (%) 0.48 0.45 0.21 0.02 0.06 0.24 1.13 0.32 0.53 0.48 0.34 0.50 0.46 0.74 0.41 0.60 0.43 0.46
The stones were classified into three groups in dependence of the dominant component content of CaO and SiO2, respectively. The FTIR analysis of the samples with CaO dominant content identified the presence of carbonates (Fig. 1a).Transmittances associated with carbonates functional groups were observed at 1394 cm-1, 872 cm-1 a 712 cm-1. The similar FTIR spectra were measured for all stone samples with CaO dominant content. Limestones differ not only in terms of their chemical composition, but also in terms of their physical properties. In nature, pure limestones are rarely occurred. Impurities of various concentrations originated from primarily processes such as sedimentation as well as from the secondary pollution, e.g. transportation of different substances by water infiltration through the limestones.
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According to the chemical composition limestones are divided in dependence of the CaCO3 content into: high-percentage with 98 % of CaCO3 contents lightly contaminated with CaCO3 content of 90 to 98 %, moderately polluted with 80 to 90 % of CaCO3 and very contaminated with concentration under 80 % of CaCO3. A specific group of ingredients is represented by magnesium oxide, which is not counted among the contaminants, but usually accompanies CaCO3 as anisomorphicad mixture [6]. Silicates usually in form of quartz and compounds of iron and aluminum are the main ingredients that accompany CaCO3. In addition to the peaks, which are typical for carbonates (Fig. 1b), there were also found the peaks corresponding to symmetric and asymmetric vibrations of quartz and silicates (1005, 796, 777, 694, 518 a 463 cm-1). In addition to the stones based on the limestone, the stones with SiO2 dominant content were identified to be built-in the constructions of the historical castle. FTIR spectrum (Fig. 1c) represents the presence of the silicate and quartz functional groups. Transmittances associated with symmetric and asymmetric vibrations of silicate and quartz functional groups were observed at 1163, 1081, 778, 694, 517 a 458 cm-1.
Fig. 1. FTIR spectrum of selected stone samples a) with CaO dominant content, b) with both CaO and SiO2, c) with SiO2 dominant content In order to identify the mineralogical composition of the analysed stone samples, the XRD analysis was performed (Fig. 3). Calcite as main mineralogical phase of limestone was identified in analyzed stone samples with majority of CaO content (Fig. 2a). The presence of silicates (2.5-7.5 %) in stone samples with majority of CaO content was identified by XRD analysis (Fig. 2b). Fig. 2c represents the XRD spectrum of stone sample with SiO2 dominant content where quartz and muscovite were identified by mineralogical analysis.
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Fig. 2. XRD spectrum of stone samples a) with CaO dominant content, b) with both CaO and SiO2, c) with SiO2 dominant content Conclusion Analysis of the stones confirmed various compositions of the used building stones in studied historical objects. Analyzed building can be divided into three types: limestone based stones with dominant content of CaO; silicate based stones with dominant content of SiO2 and building stone containing both calcite and silicates. Presence of impurities has been manifested by difference in chemical and physical properties of materials. Results of chemical and mineralogical analysis of analysed stone samples from the medieval castle will be very useful for the selection process of stone for the intended reconstruction. Acknowledgments This research has been carried out in terms of the project NFP 26220120037 and NFP 26220120018 supported from the European Union Structural Funds. This work has been supported by the Slovak Grant Agency for Science (Grant No. 1/0882/11). References [1] Identifying and Sourcing Stone for Historic Building Repair. English Heritage Publishing, 2006. [2] Stonework Repairs. Northern Ireland Environment Agency, Technical Note No. 39, 2006. [3] K.D. Weeks and E.A. Grimmer, The Secretary of the Interior’s Standards for the Treatment of Historic Properties with Guidelines for Preserving, Rehabilitating, Restoring&Reconstructing Historic Buildings, Washington, D.C., 1995. [4] Á. Török and R. Přikryl, Current methods and future trends in testing, durability analyses and provenance studies of natural stones used in historical monuments, Eng. Geol. 115 (2010) 139-142. [5] L. Binda, A. Saisi and C. Tiraboschi, Investigation procedures for the diagnosis of historic masonries, Constr. Build. Mater. 14 (2000) 199-233. [6] P.M. Amaral, J. Cruz Fernandes and L. Guerra Rosa, A Comparison between X-ray Diffraction and Petrography Techniques used to determine the Mineralogical Composition of Granite and Comparable Hard Rocks, Mat. Sci. Forum 514-516 (2006) 1628-1632.
Binders and Materials XI 10.4028/www.scientific.net/AMR.897
Analysis of Building Stone of the Medieval Historical Building 10.4028/www.scientific.net/AMR.897.305
