Conservation and Restoration of Cultural Heritage / Kültür Varlıklarını Koruma ve Onarım
Permanent URI for this collectionhttps://hdl.handle.net/11147/23
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Article Characterization of Yellow Patina on Stone Surfaces by Instrumental Analysis Including Libs(Taylor & Francis, 2022) Badur, Fulya; Aras, Nadir; Yalçın, Şerife; Böke, HasanYellow patina formed on the stone surfaces of historical buildings, monuments, and archaeological structures due to weathering is considered a value of the building in the conservation of cultural heritage studies. Although yellow patina layers can be easily distinguished on white marble surfaces, it is not possible to distinguish them on the yellow travertine surfaces with the naked eye. It should be taken into account in yellow travertines as well as marble surfaces before conservation treatments of the stone. In this study, mineralogical and chemical compositions and the thicknesses of yellow patina layers formed on yellow travertine and marble surfaces in Aizanoi, Aphrodisias, and Hierapolis archaeological sites in Turkey were analyzed in order to constitute a conservation approach in the archaeological sites. In this respect, XRD, FT-IR, SEM-EDX, and LIBS were used in the determination of compositions and thicknesses of yellow patina. Although LIBS analysis is a more convenient method to investigate patina layers on stone surfaces, this technique is not as well known as the others. Yellow patina layers contained calcium oxalate in the form of whewellite (CaC2O4.H2O). Their thicknesses were between 15 and 100 μm and should be protective against weathering on travertine and marble surfaces. Highlights LIBS analysis seems to be the most convenient micro-destructive method to estimate the thickness of the yellow patina layers on the marble and yellow travertine surfaces. The determination of the thickness of the yellow patina is critical to keep irreversible cleaning interventions, especially for the yellow travertines due to their similar colors. Yellow patina is mainly composed of calcium oxalate with clay minerals and organic compounds.Article Citation - WoS: 1Citation - Scopus: 1Plaster Characteristics of Byzantine Wall Paintings in Western Anatolia(Institute of Metals Technology, 2022) Şerifaki, Kerem; Böke, HasanIn this study, the execution technique and material characteristics of the plaster layers of Byzantine wall paintings from three archaeological sites (Anaia, Olympos and Aigai) from western Anatolia were examined for the purpose of their conservation. Throughout the study, mineralogical and chemical composition of the plaster layers were determined with a scanning electron microscope coupled with an X-ray energy dispersive system (SEM-EDS) and X-ray diffraction analyses (XRD). Reflected light microscopy (RLM) and SEM studies conducted on polished cross-sections of samples revealed the stratigraphy and microstructural properties of the plaster layers of the Anaia Church (4th–12th centuries), Baºpýnar Church (13th century) in Olympos and a Byzantine settling and the Chapel (13th century) in Aigai. Throughout the research, pure lime and aggregates in the plasters of Aigai, as well as magnesium-rich lime and straw in the plasters of Anaia and Baºpýnar were determined. The plasters from the Anaia and Baºpýnar Churches exhibit characteristics similar to the samples from the post-iconoclastic period due to a similar raw-material use. In the samples from Aigai, plastering techniques such as marmorino, intonachino and cocciopesto, indicating earlier periods, were observed. As a result of this study, it was concluded that the number and characteristics of the plaster layers from the paintings had been applied intentionally in accordance with the technique of the painting. Plaster characteristics of the wall paintings in western Anatolia from the Byzantine period were found to be similar to the ones in Ýstanbul, the Balkans, Crete and Cyprus. The results of this study will guide the conservation efforts of the wall paintings.Article Citation - WoS: 3Citation - Scopus: 3Microstructural Characteristics of Mortars Prepared by Hot Lime Mix(Union of Croatian Civil Engineers and Technicians, 2020) Şerifaki, Kerem; Uğurlu Sağın, Elif; Böke, HasanThe effect of lime characteristics and hot lime mix method on hydraulic, microstructural and mechanical properties of mortars is determined by producing mortars from quicklimes of two different marbles and two limestones. Results of SEM-EDS, XRD and TGA analyses reveal that the porous microstructure of mortars and spongy texture of calcite crystals are the indicators of the hot lime mix method. This study shows that characteristics of limestones used for the production of limes, as well as the preparation method, directly affect hydraulic, mechanical and microstructural properties of mortars.Article Citation - WoS: 27Citation - Scopus: 28Lime Mortar Technology in Ancient Eastern Roman Provinces(Elsevier, 2021) Uğurlu Sağın, Elif; Duran, Hasan Engin; Böke, HasanNatural pozzolanic aggregates were discovered during the Roman era and have been widely used in hydraulic mortar production. Despite the claims of ancient treatises, the properties of pozzolans and the technology of hydraulic lime mortars were well known and applied in the eastern provinces of the Roman Empire. In this study, the characteristics of lime mortar at the ancient sites of Aigai and Nysa located in Western Anatolia were investigated to elicit the technology applied. The raw material compositions of the mortars, the hydraulic properties of the binders, and the mineralogical and chemical compositions of the natural pozzolans used were determined via X-ray diffraction, X-ray fluorescence spectroscopy, scanning electron microscopy coupled with energy dispersive spectroscopy, and thermogravimetric analysis. The major and trace element compositions of the natural pozzolans were evaluated via multivariate statistical analysis to determine whether the same local raw material resources were used in their manufacture. The analytical results indicated that the Roman mortars were hydraulic, stiff, and durable materials due to the use of natural pozzolanic aggregates mostly comprising dacite. Although the aggregates had similar mineralogical compositions, multivariate statistical analysis revealed that their chemical compositions were clearly distinguishable, indicating the use of different sources of raw materials. Thus, it was inferred that similar pozzolan resources were known and deliberately used to produce hydraulic mortars in the eastern ancient Roman provinces.Article Citation - WoS: 171Characteristics of Brick Used as Aggregate in Historic Brick-Lime Mortars and Plasters(Elsevier Ltd., 2006) Böke, Hasan; Akkurt, Sedat; İpekoğlu, Başak; Uğurlu, ElifMortars and plasters composed of a mixture of brick powder and lime have been used since ancient times due to their hydraulic properties. In this study, raw material compositions, basic physical, mineralogical, microstructural and hydraulic properties of some historic Ottoman Bath brick-lime mortars and plasters were determined by XRD, SEM-EDS, AFM, TGA and chemical analyses. The mineralogical and chemical compositions, microstructures, morphologies and pozzolanicities of the brick powders and fragments used as aggregates in the mortars and plasters were examined to find out the relationship between hydraulic properties of the mortars and the bricks. The characteristics of bricks used in the bath domes were also determined to investigate whether the brick aggregates used in mortar and plasters were prepared from these bricks. The results indicated that the mortars and plasters were hydraulic owing to the presence of crushed brick powders that have good pozzolanicity. The brick powders bad high pozzolanicity because they contained high amounts of calcium-poor clay minerals in their raw materials that were fired at low temperatures. On the other hand, bricks used in the domes had poor pozzolanicity with different mineralogical and chemical compositions from bricks used in mortars and plasters. Based on the results of the analysis, it was thought that the bricks manufactured with high amounts of clays were consciously chosen in the preparation of hydraulic mortars and plasters. (C) 2006 Elsevier Ltd. All rights reserved.Article Citation - WoS: 20Citation - Scopus: 21Long Term Stability of Biodegradable Polymers on Building Limestone(Elsevier Ltd., 2019) Kaplan, Zişan; Böke, Hasan; Sofuoğlu, Aysun; İpekoğlu, BaşakSynthetic polymers can be replaced by biodegradable ones as adhesives, water repellents and consolidants on the stone surfaces and facades of the historic buildings in their conservation to minimize future deterioration. In this study, the long-term stability of two biodegradable polymers, polyhydroxybutyrate (PHB) and poly-L-lactide (PLA), and an acrylic polymer (Paraloid B72) which is commonly used in conservation works of artefacts, were evaluated on limestone using a UV lamp-weathering chamber (up to 104 days) for future protection studies. Chemical and morphological changes induced by an accelerated weathering test were examined by Fourier Transform Infrared spectroscopy (FT-IR) and Scanning Electron Microscopy (SEM) analyses. Protection efficiency of the polymers was determined by the changes in color, capillary water absorption, static contact angle on limestone. Paraloid B72, PHB, and PLA coatings significantly increased hydrophobicity while decreasing capillarity water absorption and caused negligible change in the color of the limestone. Protection efficiencies of PLA and PHB polymers were almost the same as that of Paraloid B72, a widely used acrylic polymer. However, PLA and PHB seemed to be favorable polymers as protective agents due to their reversibility and biodegradability, low chromatic changes, good hydrophobic behavior and good stability to weathering in reducing the effects of outdoor exposure on limestone surfaces.Conference Object Citation - WoS: 3Citation - Scopus: 4Properties of Roman Lime Mortars in Ancient Lycia Region(American Institute of Physics, 2018) Taşcı, Burcu; Böke, HasanIn this study, the characteristics of mortars used in some ancient Roman buildings located Xanthos (Antalya), Patara (Antalya) and Tlos (Mugla) in Southern Turkey were determined in order to define the properties of the new mortars to be used in the conservation works of the buildings. For this purpose, their basic physical properties, raw material compositions, mineralogical and microstructural properties were determined by X-Ray Diffraction, Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy coupled with X-Ray Energy Dispersive Spectroscopy. Analysis results indicated that the binder of the mortars composed of lime and fine aggregates have compact and uniform structure. The mortars are of low density and high porosity were produced from high calcium lime containing magnesium and natural aggregates. The lime and aggregate ratios were between 3/4 - 5/2 by weight and the aggregates with particle sizes greater than 1mm. composed the largest fraction of the aggregates. Lime composed of small size of micritic crystals due to use of aged lime puny. Aggregates were natural and mainly composed of quartz, albite, diopside and amorphous silica that may derived from the use of volcanic ash as pozzolans.Article Citation - WoS: 8Citation - Scopus: 10Interior Plastering of Ottoman Bath Buildings(Elsevier Ltd., 2019) İpekci, Emre; Uğurlu Sağın, Elif; Böke, HasanOttoman baths were peculiar buildings with their function in community life, architectural characteristics and material use. Their interior spaces were exposed to high humidity and temperatures that made the building structure vulnerable to physical, chemical, physicochemical and biological degradations. Plasters used on the interior wall surfaces were the most important agents to protect the structure from deterioration and provide durability. This study aims to exhibit the plaster characteristics of Çinili Bath in İstanbul which was an outstanding example of Ottoman baths and built by Great Architect Sinan. Basic physical properties, raw material compositions, mineralogical, microstructural and hydraulic properties of original brick-lime plasters called as horasan (khorasan) plasters used on the walls were determined by XRF, XRD, SEM-EDS and TGA. Multilayered plaster application together with the use of glazed tiles were observed on the wall surfaces of all interior spaces. The plasters were produced from pure lime and pozzolanic crushed brick or tile aggregates and hydraulic because of the pozzolanic properties of aggregates. They are stiff, compact and durable in hot and humid conditions of bath buildings due to their self-healing properties and the formation of calcium silicate hydrates and calcium aluminate hydrates at the lime-brick interfaces and in the pores of the pozzolanic brick aggregates by the reaction of lime. Characteristics of brick aggregates were compared with the construction bricks used in the building. Their chemical and mineralogical compositions revealed that the aggregates had not been produced from construction bricks. All the results indicated that brick-lime plasters were the most suitable materials for bath buildings to protect the structure from the effect of water. © 2019 The AuthorsArticle Citation - WoS: 19Citation - Scopus: 20Execution Technique and Pigment Characteristics of Byzantine Wall Paintings of Anaia Church in Western Anatolia(Elsevier Ltd., 2018) Demir, Serap; Şerifaki, Kerem; Böke, HasanIn this study, material characteristics of wall paintings executed in 11th Century Byzantine Church located in archaeological site of Anaia (Turkey) were investigated to provide historical information of the painting techniques. For this purpose, physical, chemical and mineralogical compositions of the paintings were determined by X-Ray Diffraction, Fourier Transform Infrared spectroscopy, Scanning Electron Microscopy coupled with Energy Dispersive spectroscopy and Thermo-Gravimetric Analysis. Analysis results indicated that the paintings were executed using lime-secco technique. In this technique, pigments were mixed with lime and applied on a smooth plaster layer. Pigments used were mainly iron oxides for red, yellow and purple paintings, aluminosilicates such as celadonite for green paintings and lazurite for dark blue paintings.Article Citation - WoS: 9Citation - Scopus: 10Physicochemical Properties of Glass Tesserae in Roman Terrace House From Ancient Antandros (base Glass, Opacifiers and Colorants)(Ege Üniversitesi, 2017) Kaplan, Zişan; İpekoğlu, Başak; Böke, HasanIn this study, material characteristics of glass mosaic tesserae from Antandros ancient city, western Turkey, were investigated. The main objective of this study was to determine the compositional group of the glass tesserae. Their color, mineralogical, chemical and microstructural characteristics were determined using colorimeter, x-ray diffraction, x-ray fluorescence and scanning electron microscope. The results show that all the Antandros glasses were produced by using coastal sand as Levantine I glasses and exhibit similar compositions with natron type glasses (Roman type glasses), except for lower natron levels. Lower natron levels indicate that Antandros mosaic glass may have been produced in 7th century AD or natron may have been provided from a new flux source due to the shortage of Egyptian mineral soda or due to economic reasons glass manufacturers succeeded to produce same glass with low flux addition. Antandros glass tesserae were all opacified with antimony oxides and colored with transition metal oxides which are common used in Roman Period.
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