Browsing by Author "Bayraktar, Oguzhan Yavuz"
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Publication Possibilities of disposing silica fume and waste glass powder, which are environmental wastes, by using as a substitute for Portland cement.(2021-04-01T00:00:00Z) Bayraktar, Oguzhan YavuzIn this study, the possibilities of disposal of environmental waste, silica fume, and waste glass powder as substitutes in the mortar samples in Portland cement were investigated. For this purpose, Portland cement (CEM I), silica fume (SF), waste glass powder (WGP), CEN standard sand, and water were used in mortar production. Additive cements were obtained by using the SF, WGP, and SFWGP substitution methods in Portland cement at the rates of 10, 20, 30, and 40%. The flexural strength, compressive strength, radiation permeability (determination of linear absorption coefficient), high temperature, and alkali-silica reaction (ASR) effect on SF, WGP, and SFWGP were examined and compared with the control PC 42.5R samples. Mortar samples of 40 × 40 × 160 mm size were obtained with the grouts/mortars produced, and the samples were exposed to five temperature effects, namely, 20, 150, 300, 700, and 1000 ° C. Samples kept at 20 ° C are accepted as baseline. A total of 429 samples were studied, including the cooling process in the air (spontaneously in the laboratory, 20 ° C ± 2). After the samples achieved room temperature, flexural and compressive strength tests were carried out at 28 and 90 days. Test results demonstrate that SF, WGP, and SFWGP, which are environmental wastes, can be disposed both as a pozzolanic additive material both alone and together in cement mortars, can be utilized in buildings with high fire hazard, and the sample with the highest linear absorption coefficient is the sample obtained with SFWGP, and also, the expansion values that occur in SF and WGP are less than the control sample.Pubmed Possibilities of disposing silica fume and waste glass powder, which are environmental wastes, by using as a substitute for Portland cement.(2021-04-01T00:00:00Z) Bayraktar, Oguzhan YavuzIn this study, the possibilities of disposal of environmental waste, silica fume, and waste glass powder as substitutes in the mortar samples in Portland cement were investigated. For this purpose, Portland cement (CEM I), silica fume (SF), waste glass powder (WGP), CEN standard sand, and water were used in mortar production. Additive cements were obtained by using the SF, WGP, and SFWGP substitution methods in Portland cement at the rates of 10, 20, 30, and 40%. The flexural strength, compressive strength, radiation permeability (determination of linear absorption coefficient), high temperature, and alkali-silica reaction (ASR) effect on SF, WGP, and SFWGP were examined and compared with the control PC 42.5R samples. Mortar samples of 40 × 40 × 160 mm size were obtained with the grouts/mortars produced, and the samples were exposed to five temperature effects, namely, 20, 150, 300, 700, and 1000 ° C. Samples kept at 20 ° C are accepted as baseline. A total of 429 samples were studied, including the cooling process in the air (spontaneously in the laboratory, 20 ° C ± 2). After the samples achieved room temperature, flexural and compressive strength tests were carried out at 28 and 90 days. Test results demonstrate that SF, WGP, and SFWGP, which are environmental wastes, can be disposed both as a pozzolanic additive material both alone and together in cement mortars, can be utilized in buildings with high fire hazard, and the sample with the highest linear absorption coefficient is the sample obtained with SFWGP, and also, the expansion values that occur in SF and WGP are less than the control sample.Pubmed The impact of recycled coarse aggregates obtained from waste concretes on lightweight pervious concrete properties.(2021-04-01T00:00:00Z) Kaplan, Gokhan; Gulcan, Aslinur; Cagdas, Betul; Bayraktar, Oguzhan YavuzSignificant environmental damage can result from the use of natural resources such as cement, aggregate, and water in concrete production. Thus, more sustainable alternatives for concrete production are needed to protect the environment and natural resources. In this study, lightweight pervious concrete production involving recycled coarse aggregates (RCAs) with potential to cause environmental pollution was investigated. First, RCAs were produced from concretes possessing low compressive strength and were classified. Second, pervious concretes were produced from these RCAs. Third, the mechanical properties, permeability, and abrasion strength of the pervious concretes were determined. The water/cement (w/c) ratios of the mixtures were determined to be 0.32, 0.34, and 0.36, and the aggregate/cement (a/c) ratios were selected to be 3.5 and 4. Twelve different pervious concretes were produced and tested in total. The bulk densities (BD) of the mortars varied over an interval of 1160-1080 kg/m. The aim was to design pervious concretes with lightweight bulk densities. When the w/c ratio was 0.34, the compressive, splitting tensile and abrasion strengths were high. The compressive strength of the pervious concretes varied over an interval of 1.50-2.00 MPa. It was determined that for optimal permeability, the most appropriate w/c ratio was 0.36, and the best a/c ratio was 4. When the a/c ratio was 4, the strength values were high, and as a result, the mechanical properties were poor. With respect to aggregate gradation, it was determined that a grain size distribution of 9.50-12.50 mm was most suitable for this pervious concrete. Recycled aggregates with low strength produced low strength concrete. Therefore, the pervious concrete produced in this study is most suitable for pedestrian roads where heavy vehicle traffic does not exist.Publication The possibility of fly ash and blast furnace slag disposal by using these environmental wastes as substitutes in portland cement.(2019-08-12T00:00:00Z) Bayraktar, Oguzhan Yavuz; Bayraktar, OYThe possibility of disposing of fly ash (FA) and blast furnace slag (BFS), which are environmental wastes, by using them as substitutes in portland cement was examined in this study. Portland cement (CEM I), FA, BFS, CEN standard sand, and water were used in the production of mortars. Blended cements were obtained by substituting FA, BFS, and a mixture of FA and BFS (FABFS) at 5.0%, 10.0%, 15.0%, and 20.0% ratios in portland cement. Physical (Blaine area, density, initial and final setting time, and fineness), mechanical (flexural strength and compressive strength), radiation permeability (determination of linear absorption coefficient) and high-temperature experiments were performed on the FA, BFS, and FABFS samples. Mortar prism samples with a size of 40 × 40 × 160 mm were obtained using these cements. The samples were exposed to five temperatures: 20, 150, 300, 700, and 900 °C. Mortar samples kept at 20 °C were used as references. A total of 390 samples were studied under air cooling (spontaneous cooling at 20 ± 2 °C in laboratory environment). After the mortar samples reached at room temperature, flexural strength and compressive strength tests were carried out on the 28th and 90th days. The test results showed that FA, BFS, and FABFS can be used as pozzolanic additives in cement mortars both alone and together and can be applied in buildings with a high risk of fire up to certain temperature values. The sample with the highest linear absorption coefficient was the FABFS sample, and as the sample with the lowest radiation permeability, it was determined to be appropriate for use in buildings that are exposed to radiation effects.Pubmed The possibility of fly ash and blast furnace slag disposal by using these environmental wastes as substitutes in portland cement.(2019-08-12T00:00:00Z) Bayraktar, Oguzhan YavuzThe possibility of disposing of fly ash (FA) and blast furnace slag (BFS), which are environmental wastes, by using them as substitutes in portland cement was examined in this study. Portland cement (CEM I), FA, BFS, CEN standard sand, and water were used in the production of mortars. Blended cements were obtained by substituting FA, BFS, and a mixture of FA and BFS (FABFS) at 5.0%, 10.0%, 15.0%, and 20.0% ratios in portland cement. Physical (Blaine area, density, initial and final setting time, and fineness), mechanical (flexural strength and compressive strength), radiation permeability (determination of linear absorption coefficient) and high-temperature experiments were performed on the FA, BFS, and FABFS samples. Mortar prism samples with a size of 40 × 40 × 160 mm were obtained using these cements. The samples were exposed to five temperatures: 20, 150, 300, 700, and 900 °C. Mortar samples kept at 20 °C were used as references. A total of 390 samples were studied under air cooling (spontaneous cooling at 20 ± 2 °C in laboratory environment). After the mortar samples reached at room temperature, flexural strength and compressive strength tests were carried out on the 28th and 90th days. The test results showed that FA, BFS, and FABFS can be used as pozzolanic additives in cement mortars both alone and together and can be applied in buildings with a high risk of fire up to certain temperature values. The sample with the highest linear absorption coefficient was the FABFS sample, and as the sample with the lowest radiation permeability, it was determined to be appropriate for use in buildings that are exposed to radiation effects.