Browsing by Author "Canpolat, Orhan"

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Durability Performance of Fiber-Reinforced Metakaolin-Based and Red Mud-Fly Ash-Slag Geopolymers With Recycled Aggregates
(Springer Heidelberg, 2023) Yilmaz, Arin; Ergun, Seckin; Uysal, Mucteba; Dilbas, Hasan; Aygormez, Yurdakul; Canpolat, Orhan
In the concept of green geopolymer, a good start would be if all/many of the geopolymer components were made from recycled materials. In this research, high recycled material consumption was aimed for forming a geopolymer. Binder materials were selected as 40% metakaolin, 20% fly ash, 20% granulated ground furnace slag, and 20% red mud, and, also the aggregates were selected as recycled material (50% recycled aggregate powder and 50% marble powder). In addition, different types of fibers (brass-coated steel fiber, polyamide fiber and polypropylene fiber) at different ratios (0-0.25-0.50-0.75-1.00%) were used. Compressive strength, bending strength, ultrasound pulse velocity were obtained in the tests and nonlinear fracture parameters such as initial fracture toughness and unstable fracture toughness were determined by equations. Besides, the durability properties (abrasion resistance, high-temperature (up to 600 & DEG;C) resistance, freeze-thaw (up to 300 cycles) resistance, and sodium/magnesium sulfate attack) of the best geopolymers were considered and the best series for each fiber type was determined by a decision support system. According to the test results, the bending strength was improved by curing age and all types of fibers. Besides, the first crack and unstable crack propagation are delayed by fibers. 0.75% polypropylene fiber with a high curing time (up to 56 days) can be proposed for higher performance of geopolymer. In addition, consideration of a decision support system eases finding the best solution among the huge experimental data and gives better results instead of the conventional singular evaluation approach.
Metakaolin-Based and Blast Furnace Slag-Activated Geopolymer Cement With Waste Powders
(Springer int Publ Ag, 2023) Kabirova, Aigul; Husem, Metin; Dilbas, Hasan; Uysal, Mucteba; Canpolat, Orhan
Sustainability leads a cementless materials branch in material engineering and science. Geopolymer is one part/leaf of the sustainability branch and has many advantages (i.e., less carbon emission and low energy consumption in production) attracting attention itself. The recent dizzying progress observed in geopolymers has now turned its direction towards environmentally friendly waste-based geopolymers. Accordingly, many types of waste produced in various industries have come to life in geopolymer seeming like a positive approach from the environmental point of view. However, this area is still a virgin and is worth studying. Hence, to contribute to this field, this experimental study was conducted. Accordingly, 25-50-75% basalt powder (BP), limestone powder (LSP), recycled aggregate powder (RAP), and waste marble powder (WMP) (< 63 mu m) were employed in the experiments to produce a durable and sustainable metakaolin (MK) based geopolymer with blast furnace slag (BFS). Thirteen mixtures were produced, and reference was included in the experiments. The main binder as a composition of MK, BFS, and an activator (1:2 NaOH/Na2SiO3) was considered. At the first stage of the experiments, the main properties of the geopolymer mortars were determined by conducting the tests of the mechanical properties and the physical properties. Then, the tests of the durability properties were applied to the reference and the best geopolymer specimens selected by different multi-criteria decision support methods (MCDMs). In this point, CDMs are useful tools to find the best choice and two MCDMs, such as TOPSIS and HDM, were considered to obtain the best geopolymer mix. As a result, ages-based evaluation showed that 28-day-old specimens had the high results. BP provided satisfactory results with a dense and compact structure in geopolymer. The best geopolymer mixture included 75% BP and had a significant mechanical and durability performance compared to reference with satisfactory properties. Examining the experimental results with a MCDM may give excellent results than the conventional singular evaluation technique.
Multi-Criteria Decision-Making Optimization-Based Fiber-Reinforced Waste Ceramic Powder-Based Geopolymer: Toward a Sustainable Net Zero/Low Co2 Emission Building Material
(Springernature, 2024) Kilic, Aysen Tahire; Uysal, Mucteba; Aygun, Beyza Fahriye; Nazir, Khizar; Canpolat, Orhan; Dilbas, Hasan
In this study, geopolymers (GMs) were produced using basalt fiber, polyamide fiber, and polypropylene fiber-reinforced and ground blast furnace slag (GBFS) waste ceramic powder (WCP). In the initial phase of the study, the optimal ingredient proportions were identified, and an ideal geopolymer was selected based on its highest compressive strength. Subsequently, at the second stage of the study, various fibers with differing proportions were incorporated into the ideal geopolymer, and the resulting properties were evaluated through laboratory testing. In the third stage, the optimal GMs were determined through a holistic approach, employing a multi-criteria decision-making method. A total of ten mixtures, comprising 23 properties (230 parameters in total), were subjected to a multi-criteria decision support method (TOPSIS). The optimal GM mixture with the proportions and suitable components was identified. The findings indicated that a 20% substitution of WCP with GBFS resulted in an optimal and cost-effective mixture in a 10 M NaOH solution, serving as a reference point or ideal unreinforced mixture in this research. With regard to the addition of fibers, all three types of fibers were observed to enhance the compressive, flexural, and splitting tensile strength of the WCP-GBFS-based GM. Maximum compressive strength was observed to be 60.15 MPa, while the flexural strength was 12.98 MPa and the splitting tensile strength was 3.45 MPa for the polyamide fiber (PA)-reinforced GM. Furthermore, all reinforced GMs exhibited enhanced abrasion resistance, with the inclusion of polypropylene fibers yielding the best results. Additionally, these fiber-reinforced GMs demonstrated significant resistance to high temperatures, even as temperatures increased. The TOPSIS results indicated that PA0.8 was the optimal GM, and its components with suitable components were recommended as a sustainable net zero/low CO2 emission building material.
Relative Performance of Limestone, Marble, and Basalt Powders in Replacement of a Recycled Fine Aggregate From Red Mud and Metakaolin-Based Geopolymer Mortar
(Springer int Publ Ag, 2022) Chakkor, Ouiame; Altan, Mehmet Fatih; Canpolat, Orhan; Dilbas, Hasan; Uysal, Mucteba
The current investigation was conducted to reduce the environmental impact of wastes comprising a green, sustainable recycled geopolymer composition (RGC) including granulated-ground-blast-furnace slag (GGBS), metakaolin (MK), red mud (RM) and recycled fine aggregate (RFA). In addition, leftover industrial materials, such as limestone (LS), marble (MR), and basalt (BS) powders, are employed as fillers to replace RFA in various proportions (25, 50, and 75%). Thus, a green RGC consists of wastes. Here, sodium silicate and sodium hydroxide are preferred to prepare a 12 M alkali solution for RGC. Then, physical ultrasound pulse velocity and mechanical compressive and bending strengths are applied to RGC, and the results are evaluated. In addition, to find the best solution for the RGC mixtures, TOPSIS is employed, and the best RGCs are determined for each group, with respect to their physical and mechanical properties. Also, the durability tests are conducted on RGCs determined by TOPSIS. It is found that the best RGC mixture includes 25% RFA with 75% BS.