DSpace Arşivi :: by Yazar "Celik, Ali Ihsan" değerine göre listeleniyor

Yazar "Celik, Ali Ihsan" seçeneğine göre listele

Listeleniyor 1 - 14 / 14

Buckling of axially loaded shell structures made of stainless steel
(Techno-Press, 2023) Zeybek, Ozer; Celik, Ali Ihsan; Ozkilic, Yasin Onuralp
Stainless steels are commonly employed in engineering applications since they have superior properties such as low maintenance cost, and high temperature and corrosion resistance. These features allow them to be preferred in cylindrical shell structures as well. The behavior of a cylindrical shell structure made of stainless steel can be quite different from that made of carbon steel, as the material properties differ from each other. This paper deals with buckling behavior of axially loaded cylindrical shells made of stainless-steel. For this purpose, a combined experimental and numerical study was carried out. The experimental study comprised of testing of 18 cylindrical specimens. Following the experimental study, a numerical study was first conducted to validate test results. The comparisons show that finite element models provide good agreement with test results. Then, a numerical parametric study consisting of 450 models was performed to develop more generalized design recommendations for axially compressed cylindrical shell structures made of stainless steel. A simple formula was proposed for the practical design purposes. In other words, buckling strength curve equation is developed for three different fabrication quality.
Buckling of axially loaded shell structures made of stainless steel
(Techno-Press, 2023) Zeybek, Ozer; Celik, Ali Ihsan; Ozkilic, Yasin Onuralp
Stainless steels are commonly employed in engineering applications since they have superior properties such as low maintenance cost, and high temperature and corrosion resistance. These features allow them to be preferred in cylindrical shell structures as well. The behavior of a cylindrical shell structure made of stainless steel can be quite different from that made of carbon steel, as the material properties differ from each other. This paper deals with buckling behavior of axially loaded cylindrical shells made of stainless-steel. For this purpose, a combined experimental and numerical study was carried out. The experimental study comprised of testing of 18 cylindrical specimens. Following the experimental study, a numerical study was first conducted to validate test results. The comparisons show that finite element models provide good agreement with test results. Then, a numerical parametric study consisting of 450 models was performed to develop more generalized design recommendations for axially compressed cylindrical shell structures made of stainless steel. A simple formula was proposed for the practical design purposes. In other words, buckling strength curve equation is developed for three different fabrication quality.
Effects of glass fiber on recycled fly ash and basalt powder based geopolymer concrete
(Elsevier, 2023) Celik, Ali Ihsan; Ozkilic, Yasin Onuralp; Bahrami, Alireza; Hakeem, Ibrahim Y.
This experimental study encompasses a comprehensive exploration of multiple parameters aiming to enhance the strength, workability, setting time, and environmental attributes of geopolymer concrete (GPC). A pivotal solution lies in substituting fly ash with waste basalt powder, not only reducing binder costs but also ameliorating the overall ecological footprint. A secondary signif-icant factor entails the integration of trimmed glass fibers. Throughout the experimentation process, the predominant GPC binder and fly ash underwent substitution with basalt powder at the proportions of 25%, 50%, and 75%. The mixtures were augmented with glass fibers of 3 mm, 6 mm, and 12 mm lengths, introduced at the ratios of 0.5%, 1%, 2%, and 3%. Then, the acquired samples were subjected to a 24-h curing regimen in an 85 degrees C oven. Subsequently, after a 7-day period of exposure to external conditions post-incubation, these samples were tested for both the compressive and flexural strengths. Samples incorporating a basalt ratio of 50% exhibited the highest capacities, contrasting with reduced capacities when the basalt ratio was elevated to 75%. Conversely, samples utilizing a sodium hydroxide (NaOH) molarity (M) of 12 demonstrated su-perior performance. Impressively, the compressive strength exceeding 40 MPa was achieved with the amalgamation of M 12 and 50% basalt additive. However, the workability experienced a notable reduction at the fiber ratios of 2% and 3%. The molarity concentrations did not impede the slump, workability, or setting time. A consistent setting time of 6 h was attained, and the desired workability was obtained without the need for a superplasticizer. For achieving the optimal triad of the workability, setting time, and strength, while maximizing the environmental advantages of GPC, the recommendation is to incorporate a distinct combination comprising 1-2% glass fibers (with 12 mm length), M 12, and 50% basalt powder into the mixture formulation.
Geopolymer concrete with high strength, workability and setting time using recycled steel wires and basalt powder
(Techno-Press, 2023) Celik, Ali Ihsan; Ozkilic, Yasin Onuralp
Geopolymer concrete production is interesting as it is an alternative to portland cement concrete. However, workability, setting time and strength expectations limit the sustainable application of geopolymer concrete in practice. This study aims to improve the production of geopolymer concrete to mitigate these drawbacks. The improvement in the workability and setting time were achieved with the additional use of NaOH solution whereas an increase in the strength was gained with the addition of recycled steel fibers from waste tires. In addition, the use of 25% basalt powder instead of fly ash and the addition of recycled steel fibers from waste tires improved its environmental feature. The samples with steel fiber ratios ranging between 0.5% and 5% and basalt powder of 25%, 50% and 75% were tested under both compressive and flexure forces. The compressive and flexural capacities were significantly enhanced by utilizing recycled steel fibers from waste tires. However, decreases in these capacities were detected as the basalt powder ratio increased. In general, as the waste wire ratio increased, the compressive strength gradually increased. While the compressive strength of the reference sample was 26 MPa, when the wire ratio was 5%, the compressive strength increased up to 53 MPa. With the addition of 75% basalt powder, the compressive strength decreases by 60%, but when the 3% wire ratio is reached, the compressive strength is obtained as in the reference sample. In the sample group to which 25% basalt powder was added, the flexural strength increased by 97% when the waste wire addition rate was 5%. In addition, while the energy absorption capacity was 0.66 kN in the reference sample, it increased to 12.33 kN with the addition of 5% wire. The production phase revealed that basalt powder and waste steel wire had a significant impact on the workability and setting time. Furthermore, SEM analyses were performed.
Geopolymer concrete with high strength, workability and setting time using recycled steel wires and basalt powder
(Techno-Press, 2023) Celik, Ali Ihsan; Ozkilic, Yasin Onuralp
Geopolymer concrete production is interesting as it is an alternative to portland cement concrete. However, workability, setting time and strength expectations limit the sustainable application of geopolymer concrete in practice. This study aims to improve the production of geopolymer concrete to mitigate these drawbacks. The improvement in the workability and setting time were achieved with the additional use of NaOH solution whereas an increase in the strength was gained with the addition of recycled steel fibers from waste tires. In addition, the use of 25% basalt powder instead of fly ash and the addition of recycled steel fibers from waste tires improved its environmental feature. The samples with steel fiber ratios ranging between 0.5% and 5% and basalt powder of 25%, 50% and 75% were tested under both compressive and flexure forces. The compressive and flexural capacities were significantly enhanced by utilizing recycled steel fibers from waste tires. However, decreases in these capacities were detected as the basalt powder ratio increased. In general, as the waste wire ratio increased, the compressive strength gradually increased. While the compressive strength of the reference sample was 26 MPa, when the wire ratio was 5%, the compressive strength increased up to 53 MPa. With the addition of 75% basalt powder, the compressive strength decreases by 60%, but when the 3% wire ratio is reached, the compressive strength is obtained as in the reference sample. In the sample group to which 25% basalt powder was added, the flexural strength increased by 97% when the waste wire addition rate was 5%. In addition, while the energy absorption capacity was 0.66 kN in the reference sample, it increased to 12.33 kN with the addition of 5% wire. The production phase revealed that basalt powder and waste steel wire had a significant impact on the workability and setting time. Furthermore, SEM analyses were performed.
Influence of Replacing Cement with Waste Glass on Mechanical Properties of Concrete
(Mdpi, 2022) Zeybek, Ozer; Ozkilic, Yasin Onuralp; Karalar, Memduh; Celik, Ali Ihsan; Qaidi, Shaker; Ahmad, Jawad; Burduhos-Nergis, Dumitru Doru
In this study, the effect of waste glass on the mechanical properties of concrete was examined by conducting a series of compressive strength, splitting tensile strength and flexural strength tests. According to this aim, waste glass powder (WGP) was first used as a partial replacement for cement and six different ratios of WGP were utilized in concrete production: 0%, 10%, 20%, 30%, 40%, and 50%. To examine the combined effect of different ratios of WGP on concrete performance, mixed samples (10%, 20%, 30%) were then prepared by replacing cement, and fine and coarse aggregates with both WGP and crashed glass particles. Workability and slump values of concrete produced with different amounts of waste glass were determined on the fresh state of concrete, 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 the compressive strength and splitting tensile strength of the concrete produced with waste glass. 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. According to the results obtained, a 20% substitution of WGP as cement can be considered the optimum dose. On the other hand, for concrete produced with combined WGP and crashed glass particles, mechanical properties increased up to a certain limit and then decreased owing to poor workability. Thus, 10% can be considered the optimum replacement level, as combined waste glass shows considerably higher strength and better workability properties. Furthermore, scanning electron microscope (SEM) analysis was performed to investigate the microstructure of the composition. Good adhesion was observed between the waste glass and cementitious concrete. Lastly, practical empirical equations have been developed to determine the compressive strength, splitting tensile strength, and flexure strength of concrete with different amounts of waste glass. Instead of conducting an experiment, these strength values of the concrete produced with glass powder can be easily estimated at the design stage with the help of proposed expressions.
Mechanical Behavior of Crushed Waste Glass as Replacement of Aggregates
(Mdpi, 2022) Celik, Ali Ihsan; Ozkilic, Yasin Onuralp; Zeybek, Ozer; Karalar, Memduh; Qaidi, Shaker; Ahmad, Jawad; Burduhos-Nergis, Dumitru Doru
In this study, ground glass powder and crushed waste glass were used to replace coarse and fine aggregates. Within the scope of the study, fine aggregate (FA) and coarse aggregate (CA) were changed separately with proportions of 10%, 20%, 40%, and 50%. According to the mechanical test, including compression, splitting tensile, and flexural tests, the waste glass powder creates a better pozzolanic effect and increases the strength, while the glass particles tend to decrease the strength when they are swapped with aggregates. As observed in the splitting tensile test, noteworthy progress in the tensile strength of the concrete was achieved by 14%, while the waste glass used as a fractional replacement for the fine aggregate. In samples where glass particles were swapped with CA, the tensile strength tended to decrease. It was noticed that with the adding of waste glass at 10%, 20%, 40%, and 50% of FA swapped, the increase in flexural strength was 3.2%, 6.3%, 11.1%, and 4.8%, respectively, in amount to the reference one (6.3 MPa). Scanning electron microscope (SEM) analysis consequences also confirm the strength consequences obtained from the experimental study. While it is seen that glass powder provides better bonding with cement with its pozzolanic effect and this has a positive effect on strength consequences, it is seen that voids are formed in the samples where large glass pieces are swapped with aggregate and this affects the strength negatively. Furthermore, simple equations using existing data in the literature and the consequences obtained from the current study were also developed to predict mechanical properties of the concrete with recycled glass for practical applications. Based on findings obtained from our study, 20% replacement for FA and CA with waste glass is recommended.
Mechanical performance of geopolymer concrete with micro silica fume and waste steel lathe scraps
(Elsevier, 2023) Celik, Ali Ihsan; Ozkilic, Yasin Onuralp; Bahrami, Alireza; Hakeem, Ibrahim Y.
Environmental studies for solutions are among the most important agendas of the scientific world. Most of the new studies are taking into account environmental effects. However, it is interesting for the scientific world to find solutions for accumulated environmental problems, to reduce harmful production, and to turn wastes that cause environmental pollution into useful products. In addition to incorporating fly ash, a recognized environmentally friendly and sustainable ma-terial, geopolymer concrete, utilizes micro silica fume (micro silica) as a binding agent. Furthermore, waste lathe scraps are introduced to enhance and safeguard the concrete's me-chanical properties. During the preparation phase, significant enhancements have been identified in the workability and setting time of concrete. A total of 16 test samples were prepared in this study. Micro silica of 0%, 5%, 10%, and 20%, and lathe scraps of 0%, 1%, 2%, and 3% were examined. Experimental findings revealed that incorporating 5% micro silica resulted in notable improvements in the compressive, flexural, and splitting tensile strengths, with the increases of 14.4%, 7.45%, and 6.18%, respectively. However, higher additions of 10% and 20% were found to decrease these strengths. In contrast, the inclusion of 1% lathe scraps led to considerable in-creases in the compressive, flexural, and splitting tensile strengths by 11.4%, 6.35%, and 8.23%, respectively. However, the addition of 2% and 3% lathe scraps resulted in the reduced capacity. The findings demonstrated that combining 5% micro silica with 1% lathe scraps provided the highest strength, with the improvements of 25.7%, 14.4%, and 12% in the compressive, flexural, and splitting tensile strengths, respectively. Considering the enhancements in the workability, setting time, and strengths observed in all the tests, the recommended optimal geopolymer mixture is 5% micro silica together with 1% lathe scraps.
Optimum usage of waste marble powder to reduce use of cement toward eco-friendly concrete
(Elsevier, 2023) Ozkilic, Yasin Onuralp; Zeybek, Ozer; Bahrami, Alireza; Celik, Ali Ihsan; Mydin, Md Azree Othuman; Karalar, Memduh; Hakeem, Ibrahim Y.
In this study, waste marble powder (WMP) was used to replace cement of concrete in specific amounts. To accomplish this aim, WMP was replaced at 10%, 20%, 30%, and 40% of the cement weight, and a reference concrete sample without WMP (REF) was created to compare the compressive strength, splitting tensile strength, and flexural strength. The replacement of WMP at 10%, 20%, 30%, and 40% of the cement weight resulted in 5.7%, 21.7%, 38.1%, and 43.6% decreases in the compressive strength compared with REF. Furthermore, the splitting tensile strength results commonly followed the same trend as the compressive strength. However, WMP at 10%, 20%, 30%, and 40% led to 5.3%, 8.6%, 19.4%, and 26.7% decreases in the flexural strength compared with REF. In addition, three different calculations, ranging from simple to complex, were proposed to compute me-chanical resistances of concrete with WMP. These proposed calculations for practical ap-plications were validated using values from the literature and the implications obtained from the current research. While the simple calculations were based on the strength of REF and the WMP percentages, the complex calculations were dependent on the design of the concrete mixture, age of the samples, and the WMP percentages. For the complex calcu-lations, the ANN approach was used with the help of the coefficient of determination (R2) for the K-fold cross validation method. All the proposed methods provided high accurate estimation to predict the properties of concrete with WMP. Based on the studies, utilizing 10% WMP as the replacement of cement is recommended to obtain the optimum benefits considering both mechanical and environmental aspects. Moreover, scanning electron microscope (SEM) and energy dispersive X-ray (EDX) analyses were then conducted to observe the interaction of WMP in concrete. According to the SEM analyses, some pores were detected and the interfacial transition zone was observed in the reaction zone. On the other hand, based on the EDX analyses, the presence of WMP in concrete was manifested by the presence of high levels of calcium.(c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
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.
Performance evaluation of fiber-reinforced concrete produced with steel fibers extracted from waste tire
(Frontiers Media Sa, 2022) Zeybek, Oezer; Ozkilic, Yasin Onuralp; Celik, Ali Ihsan; Deifalla, Ahmed Farouk; Ahmad, Mahmood; Sabri Sabri, Mohanad Muayad
With the increasing number of vehicles in the world, the amount of waste tires is increasing day by day. In this case, the disposal of expired tires will cause serious environmental problems. In recent years, instead of disposing of tire wastes, most of them have been started to be recycled to produce fiber-reinforced concrete. Thus, steel fibers recovered from waste tires have been preferred as an alternative to industrial steel fibers due to their environmentally friendly and low-cost advantages. In this study, an experimental study was carried out to explore the effect of fiber content on the fresh and hardened state of the concrete. To achieve this goal, compression, splitting tensile, and flexure tests were carried out to observe the performance of the concrete with tire-recycled steel fibers with the ratios of 1%, 2% and 3%. There is an improvement in the mechanical properties of the concrete with the increase of the volume fraction of the steel fiber. However, a significant reduction in workability was observed after the addition of 2% steel fibers. Therefore, it is recommended to utilize 2% tire-recycled steel fibers in practical applications. Furthermore, experimental results of concrete with tire-recycled steel fibers were collected from the literature and empirical equations based on these results were developed in order to predict the compressive and splitting tensile strengths.
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/).
The use of crushed recycled glass for alkali activated fly ash based geopolymer concrete and prediction of its capacity
(Elsevier, 2023) Ozkilic, Yasin Onuralp; Celik, Ali Ihsan; Tunc, Ufuk; Karalar, Memduh; Deifalla, Ahmed; Alomayri, Thamer; Althoey, Fadi
The influence of waste glass aggregate (WGA) with fly ash in certain proportions was studied by different amounts of molarity and WGA proportion on geopolymer concrete (GPC). For this aim, the molarity values of the NaoH concentration consumed in this investigation were determined as 11, 13 and 16. At the end of the examinations, work-ability, setting time, compression strength (CS) test, splitting tensile (ST) tests and flexural strength (FS) tests are performed. The conclusions demonstrated that the slump values increased as the molarity increased and waste glass (WG) percentages decreased. While concerning CS, ST and FS examinations, as the proportion in the combination was increased, these test results tend to decrease correspondingly. While the proportion of molarity of NaOH proportion was altered from 11 to 13 and 13 to 16, these test results tend to increase. This examination study demonstrates that glass aggregate had also a slight adverse influence on capacity and workability. Moreover, the use of 10% glass aggregate with NaOH molarity of 16 is suggested to gain the optimum sustainable GPC considering both fresh and hardening properties as the combined influence of WGA and NaOH molarity. Furthermore, in this examination, the offered strength models are established and related to those built on several standard codes. More importantly is that an equation is derived to predict the compressive strength of the geopolymer mixture utilized in this study. Additionally, scanning electron microscopy (SEM) analysis was achieved on the example parts attained from GPC examples formed with WGA.(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/).
Use of waste glass powder toward more sustainable geopolymer concrete
(Elsevier, 2023) Celik, Ali Ihsan; Tunc, Ufuk; Bahrami, Alireza; Karalar, Memduh; Mydin, Md Azree Othuman; Alomayri, Thamer; Ozkilic, Yasin Onuralp
The influence of waste glass powder (WGP) with fly ash in certain proportions on geo-polymer concrete (GPC) was investigated by exchanging different proportions of molarity and WGP percentages in GPC. For this objective, fly ash was altered with WGP having percentages of 10%, 20%, 30%, and 40%, and the effect of molarity of sodium hydroxide (NaOH) was examined. The compressive strength tests, splitting tensile tests, and flexural strength tests were conducted. The workability and setting time were also evaluated. With the addition of WGP, the workability for molarities (M) of 11, 13, and 16 NaOH reduced by an average of 17%, 10%, and 67%, respectively. The findings showed that the slump values decreased as the molarity and WGP percentages increased. Molarity significantly affected the setting time, but WGP had no effect on the setting time. Although high molarity increased the capacity, this had a noticeable negative effect on the setting time and workability. This study demonstrated that WGP had a slight negative effect on the capacity and workability. Furthermore, when the combined effects of WGP and NaOH molarity were taken into account, the use of 10% WGP with M13 NaOH was recommended to obtain the optimum sustainable GPC considering both fresh and hardening properties. Scanning electron microscopy (SEM) analysis was done on the samples, too.& COPY; 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Yazar "Celik, Ali Ihsan" seçeneğine göre listele

Sayfa Başına Sonuç

Sıralama seçenekleri