Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

Browse

Filters

2003 - 200912020 - 20222

Settings

Scopus Q: search.filters.scopusQuartile.Q3Subject: search.filters.subject.Marble

Search Results

Now showing 1 - 3 of 3
  • Article
    Characterization of Yellow Patina on Stone Surfaces by Instrumental Analysis Including Libs
    (Taylor & Francis, 2022) Badur, Fulya; Aras, Nadir; Yalçın, Şerife; Böke, Hasan
    Yellow 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: 3
    Citation - Scopus: 3
    Microstructural Characteristics of Mortars Prepared by Hot Lime Mix
    (Union of Croatian Civil Engineers and Technicians, 2020) Şerifaki, Kerem; Uğurlu Sağın, Elif; Böke, Hasan
    The 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: 8
    Citation - Scopus: 8
    Reducing Marble-So2 Reaction Rate by the Application of Certain Surfactants
    (Springer Verlag, 2003) Böke, Hasan; Gauri, K. Lal
    Sulfur dioxide (SO2), prevalent in the modern urban environment of industrial countries, attacks calcite (CaCO3) in marble. As a result, a gypsum (CaSO4.2H2O) crust is produced at rain-sheltered surfaces while areas exposed to rain experience accelerated erosion. We have investigated the effect of certain surfactants as protective agents against SO2 attack. We report that the anions oxalate (C2O4-2) and oleate (C17H33COO-) from solutions of their highly soluble alkali salt species are able to replace carbonate (CO3-2) in calcite producing less reactive substrate of oxalate and oleate of calcium. Experiments to measure the protection obtained by these treatments were carried out in the laboratory and field conditions at nearly 1 ppm and 10 ppb SO2 concentrations, respectively. We found that these treatments provided significant protection to marble exposed in sheltered areas, up to 30% reduction of reaction rate by treatment with 2 × 10-4 M sodium oleate and up to 14% by a 2 × 10-3 M with potassium oxalate solutions, but become ineffective over long term exposure when applied to surfaces exposed to rain. Carrara marble was used in the reported study. Ion chromatography was the analytical tool, which allowed precise measurements of ionic concentrations of these salts, the amount of their uptake by marble, and the thickness of the gypsum crust. X-ray diffraction allowed determination of the new minerals formed at the marble surface by the treatment with surfactants.