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: 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: 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.Article Citation - WoS: 29Citation - Scopus: 35Sustainable Bio-Nano Composite Coatings for the Protection of Marble Surfaces(Elsevier Masson SAS, 2015) Ocak, Y.; Sofuoglu, A.; Tihminlioglu, F.; Böke, H.Water repellency on natural stone surfaces is the most important issue in the protection of stone monuments from effects of atmospheric pollutants. In this study, effectiveness of a bio-nano composite coating, composed of a biodegradable polymer (poly-L-lactide [PLA]) and montmorillonite clay (MMT) was investigated for the protection of marble surfaces from pollution. The clay dispersion in polymer matrices was analyzed by using Scanning Tunnel Electron Microscopy (STEM) and X-Ray Diffraction (XRD), while protection performance was investigated by the measurement of surface roughness, wettability, water vapor permeability, capillary water absorption, and color changes on the marble surfaces. As a result, no alteration on the color of coated marbles was observed, significant improvement was obtained for hydrophobicity of the surface and inhibition of sulfation reaction on the exposed marble surfaces under acidic atmosphere. It could be said that PLA based nanocomposites seem to be promising materials as protective coating agents in reducing the effects of water and atmospheric pollutants on marble surfaces. © 2014 Elsevier Masson SAS.Article Citation - WoS: 21Citation - Scopus: 23Determination of Caco 3 and Sio 2 Content in the Binders of Historic Lime Mortars(Springer Verlag, 2012) Uğurlu Sağın, Elif; Böke, Hasan; Aras, Nadir; Yalçın, ŞerifeThe binders of historic mortars composed of small grain sized silica (SiO 2) and carbonated lime (CaCO 3) are considered as the main part that give hydraulic character and high strength to the mortar. In this study, FTIR, SEM-EDS, LIBS and XRD spectroscopy were used to find out the weight ratios of CaCO 3 to SiO 2 in the binders of historic lime mortars. For this purpose, a series of pure calcium carbonate and silica mixture were prepared in ten combinations in varying ratios from 0.5 to 5. Calibration curve was prepared for each analysis by plotting the peak area or intensity ratios of CaCO 3 to SiO 2 versus the weight ratios of CaCO 3 to SiO 2. A good linear correlation coefficient was obtained for each analysis respectively. The analyses were then tested on the binder of the Roman mortar samples. The results indicated that FTIR, SEM-EDS and LIBS spectroscopy are convenient tools to determine the weight ratios of CaCO 3 to SiO 2 in the binders of mortars. But XRD spectroscopy is not convenient for quantitative analysis of binders due to the presence of varied amounts of amorphous or poor crystalline silica in their compositions.Article Citation - WoS: 28Citation - Scopus: 29Characteristics of Bricks Used in the Domes of Some Historic Bath Buildings(Elsevier Ltd., 2013) Uğurlu Sağın, Elif; Böke, HasanIn this study, characteristics of bricks used in the domes of some historic bath buildings dated to 15th century in Izmir were determined in order to indicate the properties of repair bricks that will be used in the conservation works of the domes. For this purpose, their basic physical properties, elemental and mineralogical compositions, firing temperatures and microstructural properties were determined by using XRF, XRD, SEM-EDS and TGA analysis. Analysis results indicated that the bricks are of low density, high porosity and were produced from raw materials containing low amounts of calcium poor clays fired at low temperatures (<. 900. °C). They are mainly consisted of small pores with r<. 5. μm that make the bricks more susceptible to salt crystallization and freeze-thaw cycles. Although the bricks were fired at low temperatures and susceptible to salt crystallization and freeze thaw cycles, the structural systems of the domes remained without losing their integrity due to the moderate climatic conditions of Izmir. Repair bricks that will be used in the conservation works of the domes should be compatible with the original ones and produced from calcium poor clays by firing at low temperatures.