Yazar "Ozdoner, Nebi" seçeneğine göre listele

Listeleniyor 1 - 5 / 5
  • Küçük Resim Yok
    Öğe
    Application of waste ceramic powder as a cement replacement in reinforced concrete beams toward sustainable usage in construction
    (Elsevier, 2023) Aksoylu, Ceyhun; Oztilic, Yasin Onuralp; Bahrami, Alireza; Yildizel, Sadik Alper; Hakeem, Ibrahim Y.; Ozdoner, Nebi; Basaran, Bogachan
    The main purpose of this study was to investigate the flexural behavior of reinforced concrete beams (RCBs) containing waste ceramic powder (CP) as partial replacement of cement. For this purpose, flexural tests were carried out using various amounts of mixing ratios. By determining the amount of CP utilized in the optimum ratios, it was aimed both to make predictions for design engineers and to show its beneficial effect on the environment by recycling the waste material. For this purpose, twelve specimens were produced and verified to monitor the flexural behavior. The longitudinal reinforcements percentage (0.77%, 1.21%, and 1.74%) and CP percentage (0%, 10%, 20%, and 30%) were chosen as the parameters. CP could be effectively used up to 10% of cement as a replacement material. Increasing the CP percentage by more than 10% could considerably reduce the load-carrying capacity, ductility, and stiffness of RCBs, specifically when the longitudinal reinforcements percentage was high. In other words, as CP increased from 0% to 30%, the load-carrying capacity decreased between 0.4% and 27.5% compared with RCBs with the longitudinal tension reinforcements of 2 phi 8 without CP. However, reductions of 5.5-39.8% and 2.15-39.5% in the load-carrying capacity occurred respectively compared with RCBs with the longitudinal tension reinforcements of 2 phi 10 and 2 phi 12 without CP. The achieved longitudinal reinforcements percentage was close to the balanced ratio, while more than 10% CP cannot be used without any precautions for mixtures.
  • Küçük Resim Yok
    Öğe
    Excessive snow induced steel roof failures in Turkey
    (Pergamon-Elsevier Science Ltd, 2022) Korkmaz, Hasan Husnu; Dere, Yunus; Ozkilic, Yasin Onuralp; Bozkurt, Mehmet Bakir; Ecemis, Ali Serdar; Ozdoner, Nebi
    In January 2017, collapses of the numerous roofs were reported due to excessive snowfall in many provinces of Turkey. In this study, the reasons behind the collapses of the steel roofs of 19 factory buildings were investigated. The steel roofs supported by the precast reinforced concrete columns indicated a similar collapse pattern to each other under the unexpected heavy snow loading. The failure mechanisms of the roofs under the snow loading were simulated numerically. Nonlinear finite element models of a typical industrial building were developed and analyzed under an incremental vertical loading that is identical to snow loading. As a result of the analysis, the vertical load carrying capacity of the roof system and the snow load level causing the collapse of roof were determined. The resulting snow load was compared with the snow load values provided by the code specifications. In addition, the collapse mechanism of the steel roof system was analytically determined and compared with the collapse modes observed in the field and the causes of the failure were evaluated. The failure mechanism and the buckling modes obtained from analyses were found very similar to those observed during the site inspections. The main reasons of the roof failures may be attributed to excessive amount of snow caused by climate change and discrepancy of designed project and as-built project due to lack of building inspection control during the construction of the buildings.
  • Küçük Resim Yok
    Öğe
    Performance Assessment of Fiber-Reinforced Concrete Produced with Waste Lathe Fibers
    (Mdpi, 2022) Celik, Ali Ihsan; Ozkilic, Yasin Onuralp; Zeybek, Ozer; Ozdoner, Nebi; Tayeh, Bassam A.
    The amount of steel waste produced is on the increase due to improvements in steel manufacturing industries. The increase in such wastes causes significant environmental problems and, furthermore, a large area is also required to store these waste products. Instead of disposing of these wastes, the reuse of them in different industries is an important success in terms of both reducing environmental pollution and providing low-cost products. From this motivation, the effect of lathe scrap fibers generated from Computer Numerical Control (CNC) lathe machine tools on concrete performance was investigated in this study. Pursuant to this aim and considering different fiber content, an experimental study was conducted on some test specimens. Workability and slump values of concrete produced with different lathe scrap fibers were determined, and these properties were compared with those of plain concrete. For the hardened concrete, 150 mm x 150 mm x 150 mm cubic specimens and cylindrical specimens with a diameter of 100 mm and a height of 200 mm were tested to identify compressive strength and splitting tensile strength of the concrete produced with different volume fracture of lathe waste scrap (0%, 1%, 2% and 3%). With the addition of the lathe scrap, the compressive and splitting tensile strength of fiber-reinforced concrete increases, but after a certain value of steel fiber content, there is a decrease in workability. Next, a three-point bending test was carried out on samples with dimensions of 100 x 100 x 400 mm and a span length of 300 mm to obtain the flexure behavior of different mixtures. It has been shown that the flexural strength of fiber-reinforced concrete increases with an increasing content of waste lathe. Furthermore, microstructural analysis was performed to observe the interaction between lathe scrap fiber and concrete. Good adhesion was observed between the steel fiber and cementitious concrete. According to the results obtained, waste lathe scrap fiber also worked as a good crack arrestor. Lastly, practical empirical equations were developed to calculate the compressive strength and splitting tensile strength of fiber-reinforced concrete produced with waste lathe scrap.
  • Küçük Resim Yok
    Öğe
    Production of perlite-based-aerated geopolymer using hydrogen peroxide as eco-friendly material for energy-efficient buildings
    (Elsevier, 2023) Acar, Mehmet Cemal; Celik, Ali Ihsan; Kayabasi, Ramazan; Sener, Ahmet; Ozdoner, Nebi; Ozkilic, Yasin Onuralp
    Using ground raw perlite through alkali activation to produce various construction materials such as plaster, grouting, and concrete can provide economic and environmental advan-tages by reducing Portland cement consumption. It is aimed to produce cementless pastes and cementless mortars based on the alkali activation of raw perlite and standard sand for this study. Perlite and alkali activators (NaOH and Na2SiO3) were used as binding materials to produce cementless paste and mortar. In addition, aerated lightweight pastes and mor-tars were produced using hydrogen peroxide (H2O2) as a blowing agent. Thus, the aeration mechanism of the sample was examined, and the changes in apparent density, compressive strength, and flexural strength values were determined. At the same time, the thermal conductivity properties of aerated paste and mortars were investigated. Geopolymers in various Water/Perlite and H2O2/Perlite ratios were produced, and their thermal conductivity, apparent density, compressive and flexural strength were contrasted. The experimental finding revealed that adding 0.25% H2O2 (by mass of perlite) to the mixtures enabled the production of lightweight pastes and mortars with lower density and lower thermal con-ductivity coefficient without a significant loss of ultimate strength. The developed perlite based aerated geopolymer is a eco-friendly and energy efficient solution to the buildings. Based on the results, H2O2/Perlite% above 0.5% and water/Perlite% above 45% should be avoided for both paste and mortars. In order to obtain optimum results in terms of work-ability, strength, density, and thermal conductivity, it is recommended that the H2O2/Perlite ratio for all samples should be 0.25% and the Water/Perlite percentage should be 40%. (c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
  • Küçük Resim Yok
    Öğe
    Shear and Bending Performances of Reinforced Concrete Beams with Different Sizes of Circular Openings
    (Mdpi, 2023) Ozkilic, Yasin Onuralp; Aksoylu, Ceyhun; Hakeem, Ibrahim Y.; Ozdoner, Nebi; Kalkan, Ilker; Karalar, Memduh; Stel'makh, Sergey A.
    The present study pertains to the effects of transverse opening diameters and shear reinforcement ratios on the shear and flexural behavior of RC beams with two web openings across different spans, i.e., a single opening in each half-span. Within the scope of the study, a total of 12 RC beams with five different opening diameter-to-beam depth ratios (0, 0.20, 0.27, 0.33, 0.40, and 0.47) and two shear reinforcement ratios were tested to failure under four-point bending. The load capacities, ductilities, rigidities and energy dissipation capacities in the elastic and plastic ranges of beam behavior were compared. Furthermore, the load capacities of the beams were compared to the existing analytical shear strength formulations in the literature. The test results indicated that whether an RC beam with openings has adequate or inadequate amounts of shear reinforcement, the frame-type shear failure becomes much more pronounced with increasing opening diameter. The reductions in the load capacity and modulus of toughness with increasing opening diameter are more considerable in the presence of inadequate amounts of shear reinforcement, while the beam ductility is less affected in shear-deficient RC beams with openings as compared to the ones with adequate shear reinforcement.