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Öğe A Comparative study on the activity of oxygenic photosynthetic consortia on marble and granite(INT ASSOC COMPUTER SCIENCE & INFORMATION TECHNOLOGY PRESS-IACSIT PRESS, 2011) Karaca, Zeki; Ozturk, Ayten; Unsal, Tuba; Dan, YThis Many kinds of microorganisms are playing key role in degradation of historical artifacts, buildings and monuments made of marble, granite and other dimension stones. It is well known that, photoautotrophic microorganisms predispose the stone surface as a breeding-ground for other group of microorganisms. However, the effects of photoautotrophic and other microorganisms on stone materials, where hygiene is crucial, are not well known. Until now, the relation between microorganisms and rock properties and its effect on usage is not investigated. In this study; the biological weathering of AW (true marble) and BP (granite) has been investigated in laboratory condition. Both stone surfaces also supported a heavy colonization of phototrophic microbial consortia (outer and inner part, respectively). After phototrophic microbial growth on AW and BP, while AW turned to yellowish green from original white color, BP turned to green from original grey color. Inner sides of stones, filamentous biota, are possible member of cyanobacteria, were dominant. However, small spherical aggregates, possible calcified globular bodies on the stones were detected with SEM studies.Öğe Assessment of the results of the pendulum friction tester (EN 14231) for natural building stones used as floor-coverings(ELSEVIER SCI LTD, 2013) Karaca, Zeki; Gurcan, Sevgi; Gokce, Mehmedi Vehbi; Sivrikaya, OsmanThe main scope and parameter in choosing stone materials for floorings are unquestionably safety and slip resistance. The standard "EN 14231" is one of those developed for natural stones. The device used for the tests of this standard, "the pendulum coefficient friction tester", determines the slip resistance value of floorings in angle. Standards and their testers have constantly being developed. When this point of view is considered, EN 14231 has not yet been criticized. In this study, EN 14231 and the results obtained by the pendulum tester were for the first time analysed in terms of characteristics expected from a standard. For experimental studies, marble, limestone, travertine and granite samples currently in use as natural building materials were used. For each type of stone, four well-known and widely used stones that had surface roughness less than 1 mm were chosen. In this respect, 384 pendulum tests were conducted on 192 samples and more than 2200 angles were read from F scale. Depending on these readings, the dry slip resistance value-wet slip resistance value (DSRV-WSRV) relationships of marbles, limestone, travertine, and granites were investigated. Except travertine, DSRV-surface roughness and WSRV- surface roughness relationships of the samples were investigated. In addition, DSRV- cavity surface area and WSRV- cavity surface area relationships of travertine samples were investigated. After the evaluation of the test results, it was observed that, in general, higher correlations were obtained from wet samples compared to dry ones. The highest correlations were obtained from wet limestone samples. On the other hand, the lowest correlations were determined on the marble samples. Besides, petrographic characteristics and the physical characteristics of the stones such as, surface roughness and surface cavities were not recorded to have had any determinative effects on the results of the pendulum tester. According to the data obtained in this study, EN 14231 and the pendulum tester were seen to have fallen short in distinguishing both different types of natural stones and different groups of the same type of stone. For this reason, new researches should be made on EN 14231 and the pendulum tester device and both should be developed further. In the light of these results, EN 14231 was concluded to have been unsatisfying in terms of the characteristics expected from a standard and its applicability for slip resistance tests of stone materials to be used in floorings. (C) 2013 Elsevier Ltd. All rights reserved.Öğe Biofouling of marbles by oxygenic photosynthetic microorganisms(SPRINGER HEIDELBERG, 2015) Karaca, Zeki; Ozturk, Ayten; Colak, EmelPhototrophic microorganisms disfigure the surfaces of different types of stone. Stone structure is damaged by the activity of photoautotrophic and other microorganisms. However, to date few, investigations have been undertaken into the relationship between microorganisms and the properties of different types of marble. In this study, biological activity of photoautotrophic microorganisms on three types of marble (Yatagan White, Giallo Anticato and Afyon White) was investigated under laboratory conditions over a short period of time. The three types of marble supported the growth of phototrophic microbial communities on their outer and inner layers, turning their original colour from white to a yellowish green colour. The porosity of the marble types facilitated filamentous microbial growth in the presence of water. Scanning electron microscope analysis revealed the accumulation of aggregates such as small spherical, fibrillar, calcified globular bodies on the inner surfaces of the marbles. This suggests that the microscopic characteristics of particular marble types may stimulate the growth of certain types of microorganisms.Öğe Effect of freeze-thaw process on the abrasion loss value of stones(PERGAMON-ELSEVIER SCIENCE LTD, 2010) Karaca, Zeki; Deliormanli, Ahmet Hamdi; Elci, Hakan; Pamukcu, Cagatay[Abstract Not Available]Öğe Effects of surface-finishing forms and cement-filling on porous dimension limestone deterioration in cold regions(ELSEVIER SCIENCE BV, 2011) Karaca, Zeki; Oztank, Nimet; Gokce, Mehmedi Vehbi; Elci, HakanThis work studies the influences of both surface-finishing forms and cement-filling on the durability of dimension limestone in cold regions. Freeze-thaw cycles, aqueous saline solution and their interactions with surface-finishing forms and cement-filling on stones were investigated for two types of porous limestone, Caribbean and Pewter Blend. Both deionised water and saline water composed of 20% NaCl by weight were used, and 28 freeze-thaw cycles were applied to the samples. The change in dry weight, porosity, and Bohme abrasion loss value was obtained for all test samples. It was observed that two types of porous limestone with cement-filling and different types of surface-finishing were influenced to different extents by freeze-thaw and salt. Experiments showed that stones to be used outdoors in cold regions should have relatively low initial porosity and that they should be fine-finished and cement-filled; these modifications to the stones will maximise the benefit received from the stones. (C) 2011 Elsevier B.V. All rights reserved.Öğe Grain properties, grain-boundary interactions and their effects on the characteristics of marbles used as building Stones(ELSEVIER SCI LTD, 2015) Karaca, Zeki; Hacimustafaoglu, Ramazan; Gokce, Mehmedi VehbiIn this study, the effects of relationships of micro-structure, grain size and grain boundary of 15 well-known worldwide marbles on some physical and mechanical properties (dry unit weight, porosity, uniaxial compressive strength, tensile strength) and on abrasion loss value were investigated in detail, being the first in terms of elaborateness in the literature considering the mentioned features. 10 different samples were tested for each marble in each test. Microscope images were grouped as intergranular properties (shape of grains, shape of grain aggregates, grain boundary type and pressure solution), intra-granular properties (twinning and alteration) and deformation. All marbles which were tested were found to be of heteroblastic texture. Nine samples were monomineralic marble while six were polymineralic. It was determined that grain characteristics and grain boundary interaction affected dry unit weight, porosity, uniaxial compressive strength, tensile strength and abrasion loss value of each marble tested. (C) 2015 Elsevier Ltd. All rights reserved.Öğe Recycling waste from natural stone processing plants to stabilise clayey soil(SPRINGER, 2014) Sivrikaya, Osman; Kiyildi, Koray R.; Karaca, ZekiFor the countries with a developed stone industry the waste generated in the natural stone processing plants pose environmental and economic problems. The utilisation of stone waste in various areas is still under research. In addition, there are only a limited number of studies concerning the use of stone waste obtained from processing plants in the stabilisation of clayey soil. Furthermore, none of the studies in the literature investigated the effect of the characteristics of the stone on the stabilisation of the soil. This is the first study that compares the efficiency of the waste calcitic marble, dolomitic marble and granite powder as additives for the stabilisation of clayey soil. Artificial soil samples were prepared in the laboratory using bentonite and kaolinite. Natural stone waste powder was added to the soil samples at different percentages, and the index and compaction parameters of the stabilised soil were analysed. The results showed that the types of waste powder used in this study, like lime, could be used as stabilisers. As the percentage of additives increased, the plasticity index of the clayey soil decreased and the physical properties of the soil changed from clay to silt. In terms of compaction parameters, the use of all types of natural waste powder in the study resulted in a decrease in the optimum water content and an increase in the maximum dry unit weight. The lowest optimum water content and the highest maximum dry unit weight were obtained from the dolomitic marble powder.Öğe The Activity of Oxygenic Photosynthetic Microbial Consortia on Different Granites(FOUNDATION ENVIRONMENTAL PROTECTION & RESEARCH-FEPR, 2014) Ozturk, Ayten; Karaca, Zeki; Unsal, TubaDeterioration of stone is a combined process caused by physical, chemical and biological factors especially, microbial growth. Various microorganisms are playing a key role in the weathering of historical artifacts, buildings, and monuments made of granite, marble, and other dimension stones. In this study, the biodeterioration of three types granite, Blue Pearl from Norway, Pergamon Grey from Turkey, and Rosa Porrino from Spain were studied for thirty days under laboratory conditions. The results showed that two of the granite surfaces, Pergamon Grey and Rosa Porrino, supported a heavy colonization of phototrophic microbial consortia. These results also showed that filamentous phototrophic microorganisms were dominant on the surfaces of the granites and indicated that the porosity, the availability of water and chemical composition of the granite have encouraged colonization and caused modification on the surfaces. The filamentous aggregates, possibly calcified fibrillar bodies in the inner parts of granites were also detected by SEM studies.Öğe The Relationship Between Mineral Content and Flocculant Characteristics for Slurry Waste Water Recycling at Marble Processing Plants(SPRINGER HEIDELBERG, 2016) Bayel, Diler Katircioglu; Karaca, Zeki; Onen, Vildan; Deliormanli, Ahmet HamdiThe requirements for clean water in marble processing are partially realized by treating and recycling slurry wastes from the cutting and processing plant. In this study, the flocculation of calcitic and dolomitic (21.2 % MgO) marble wastes was investigated using six flocculants with different molecular weights and anionic levels. Nine solutions between 0.1 and 2.5 mg/L were prepared, and marble waste samples were treated in natural, slightly acidic, and alkaline media. The anionic flocculants had a more dramatic effect on the slower-settling dolomitic marble than the calcitic marble. Calcite precipitation was better in an alkaline medium, while dolomitic marble precipitation was better at a slightly acidic pH of 6.
