Browsing by Author "Dilbas, Hasan"
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Article Alternating Current Curing of Conductive Fly Ash-Slag Geopolymer Mortars: Performance, Characterization and Optimization(Springernature, 2024) Aygun, Beyza Fahriye; Uysal, Mucteba; Bilir, Turhan; Cosgun, Turgay; Dilbas, HasanThis research seeks to pinpoint the most robust series by subjecting geopolymer mortars (GMs) to electrical curing (AC) at 20 V based on different NaOH concentrations and GBFS/FA ratios. To enhance the electrical conductivity of GMs displaying optimal mechanical properties, carbon fiber (CF), steel fiber (SF), waste wire erosion (WWE) (0.25%, 0.50%, and 0.75%), and carbon black (CB) (1%, 2%, and 3%) were introduced into the chosen series. A comprehensive assessment encompassing compressive strength, flexural strength, ultrasonic pulse velocities, direct tensile strength and splitting tensile strengths were conducted on mixtures undergoing 24 h of AC. The study's findings indicated a substantial improvement in mechanical properties through electrical curing compared to ambient curing conditions. Notably, a correlation of up to 99% was established between direct and splitting tensile properties. The investigation revealed that the highest compressive strength, reaching 72.41 MPa at 1 day strength, was achieved through the thermal curing method with electric curing, particularly in the 100GBFS series. On the other hand, the optimum bending strength, approximately 19 MPa, was observed in the SFA075WWE series. These results highlight the efficacy of the thermal curing method with electric curing in enhancing the compressive strength of the 100GBFS series and the flexural strength of the SFA075WWE series, underscoring the potential benefits of specific curing methods for different series within the study.Article Çeşitli Dayanımlara Sahip Atık Betonlardan Üretilen Geri Kazanılmış Agregaların Fiziksel ve Geomekanik Özellikleri(2021) Dilbas, HasanBu basit ve kapsamlı çalışma, geri kazanılmış agreganın (RA) temel özelliklerini araştırmaktadır ve mevcut agrega standartlarına ek olarak, bu makale RA’nın yoğunluğunu ve su absorpsiyonunu kısa sürede tahmin etmek için basit bir tahmin yaklaşımını önermektedir. Bilindiği gibi, fiziksel testler uzunzaman almaktadır (yaklaşık 72 saat) ve atığın hızlı karakterizasyonu, özellikle geri dönüşüm tesisleri için daha önemlidir. Dolayısıyla, sonuçları genelleştirmek için yapılan testlerde düşük, orta ve yüksek dayanımlı atık betonlardan üretilen RA’lar dikkate alınmıştır. RA’nın temel özellikleri yoğunluk ve su absorpsiyonu olarak kabul edilebilir ve RA'ların geomekanik özelliklerini belirlemek için nokta yük testi kullanılmıştır. Nokta yük testinin dikkate alınmasının nedenleri, testin basitliği ve kısa test süresidir. Elde edilen deney sonuçları dikkate alınarak incelemelerde bulunulmuştur. Ayrıca, RA'nın fiziksel özelliklerini, nokta yük dayanım indeksi (Is(50)) kullanılarak tahmin etmek için denklemler önerilmiş ve tatmin edici sonuçlar elde edilmiştirArticle Clustering Analysis of Compressive Strength of Structural Recycled Aggregate Concrete(Kare Publishing, 2024) Dilbas, Hasan; Güneş, Mehmet ŞamilClustering analysis primarily highlights the in homogeneity of data and can be utilized in structural engineering to demonstrate strength irregularity. It is well-known that strength irregularity between neighboring floors within a structure or among structural elements can lead to non-holistic behavior. Therefore, the clustering of compressive strength holds significant importance. Despite the relevance, only a few studies have addressed the clustering of compressive strength in recycled aggregate concrete (RAC) and proposed potential solutions for clustering issues. This paper aims to investigate the clustering of compressive strength in RAC and explore viable solutions. In this experimental study, four concrete groups were produced under standard conditions. The first group included natural aggregate concretes (NAC) designed with the Absolute Volume Method (AVM) as control concretes. The second group, comprised of RAC, was designed with the equivalent mortar volume method (EVM) as the control RAC. The third group consisted of RAC treated with silica fume (SF) and designed using AVM, while the fourth group included RAC designed with EVM. Statistical analyses were conducted on the 28-day compressive strength test results. The results indicated that the strength class of compressive strength clusters varied among the four groups. The clustering of test results was influenced by the type of concrete components used and the design method employed. Additionally, using silica fume and adopting the Absolute Volume Method reduced strength fluctuation and regulated the strength class of clusters by bringing them closer together. In contrast, the Equivalent Mortar Volume Method resulted in a greater dispersion of strength classes. The clustering effect of recycled aggregate (RA) was more pronounced than that of natural aggregate (NA). Given these findings, it is essential to implement measures when utilizing RAC in sustainable structures to address potential clustering issues.Article 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, OrhanIn 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.Article Durability Properties of Treated Recycled Aggregate Concrete: Effect of Optimized Ball Mill Method(Elsevier Sci Ltd, 2021) Cakir, Ozgur; Dilbas, HasanIn this paper, effects of optimized Ball Mill Method (oBMM) with silica fume (SF) and/or basalt fiber (BF) on durability of untreated recycled aggregate concrete (RAC) and treated recycled aggregate concrete (RAiC) are investigated. 84 concrete series were designed in the experimental program and it is aimed to find the best series objectively depending on experimental results. In the program, many concrete series included natural aggregate (NA), recycled aggregate (RA) and treated RA by oBMM (RAi) and SF, BF SF + BF at various ratios were produced. The physical and the mechanical properties of concretes were determined at the age of 28 days. TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) was considered to select the best concrete series among 84 series. Then, the durability properties of the selected series were determined at the age of 28 days and the test results were compared. According to the test results, it was found that RAi decreased the performance of concrete marginally and oBMM caused a significant improvement compared to RAC. TOPSIS was a useful method to determine the best concrete series and could be used objectively if the weighting coefficients of TOPSIS depended on literature data. It was interesting that the best concrete series determined by TOPSIS were found including 10% SF only for each RA replacement proportions (these are 20%, 40% and 60% by volume) and the best series had satisfactory durability properties in comparison to control concrete. In addition, the durability performance of the best series included up to 60% RAi was generally superior to that of RA. (C) 2020 Elsevier Ltd. All rights reserved.Article Düşük, Orta ve Yüksek Dayanım için Karar Ağacı Algoritmasıyla Beton Karışım Tasarımı(2022) Dilbas, Hasan; Güneş, Mehmet Şamil; Parim, CoskunBu makale çalışmasında, mineral katkılı (silis dumanı) ve katkısız betonların karışım tasarımı için karar ağacı algoritmasıyla karışım tasarımı parametreleri 470 adet betona ait 3760 veri derlenerek belirlenmiştir. Elde edilen sonuçlar üzerinde yorumlar ve irdelemeler yapılmıştır. Karar ağacı algoritması sonuçları incelendiğinde, beton karışımları üzerinde en etkili parametreler belirlenmiştir. Elde edilen sonuçlar göstermektedir ki, her bir basınç dayanımı aralığı için en önemli parametre çimento dozajıdır ve diğer parametreler önem derecesine bağlı olarak daha sonra gelmektedir. Diğer yönden, yüksek basınç dayanımları arzulanması durumunda, ince madde içeriğinin belirtilen değerlere yakın olarak seçilmesi gerekli olup ince agreganın boşluk doldurucu etkisi ve sonucu olarak kompakt beton oluşumu/yüksek basınç dayanımı elde edilmesi ilişkisini göstermektedir denilebilir. Ayrıca elde edilen analiz sonucu farklı dayanım aralıkları için hangi karışım içeriğinden hangi miktarlarda seçilmesi gerektiğine %75 doğrulukla bir çözüm getirilmektedir. Böylelikle, beton karışım tasarımı için geliştirilmiş ilgili standartlardaki (örneğin, TS 802) detaylardan bağımsız olarak hangi dayanım için hangi beton içeriğinin seçilebileceği önerisi literatür verisi ile desteklenerek sağlanmıştır.Article Effect of Cement Type and Water-To Ratio on Fresh Properties of Superabsorbent Polymer-Modified Cement Paste(Mdpi, 2023) Dilbas, HasanSuperabsorbent polymer (SAP) is a material with the ability to absorb liquid and desorb liquid from and to the environment, and it can ensure the internal curing of cementitious composites. Although the fresh state properties of SAP-modified mixtures (SAPCP) are affected and have been investigated nowadays, the rheological properties of SAPCP are still a virgin field and they are worth studying. Hence, the current study was aimed and conducted to observe what occurred if cements with different chemical compositions, various ratios of water/cement (w/c) and SAP were used together. Accordingly, CEM I 42.5R, CEM II/A-LL 42.5R and CEM IV/B (P) 32.5R were selected as binders in the mixtures, and w/c ratios were 0.40 and 0.50 for SAPCPs. In total, 24 mixtures were designed, produced and tested in the laboratory and spreading table tests, Vicate tests, viscosity tests and shear tests were conducted on the fresh state of the mixtures to observe the fresh behavior of SAPCPs. As a result, it was determined that the SAP, cement and w/c combinations considered in the article were effective on SAPCP fresh properties and rheology. However, it was determined that the use of high amounts of SAP in the mixture, high cement fineness and high oxide ratios in the cement (ratios of silicon dioxide/calcium oxide and aluminum oxide/calcium oxide) negatively affected not only the fresh state properties, but also the rheology. Moreover, the coexistence of the aforementioned negative conditions was the most unfavorable situation: high SAP ratio + high cement fineness + high oxide ratio in SAPCP. For these reasons, it was concluded that cement fineness and chemical composition should be taken into account in the rheology/workability-based design of SAPCPs. Then, the SAP content can be regulated for design purposes.Master Thesis Effect of Number of Neurons and Layers in Artificial Neural Network and Membership and Defuzzification Functions on Fuzzy Logic for Prediction of Lateral Confinement Coefficient of Carbon Fiber Reinforced Polymer (cfrp) Strengthened Columns(2024) Kaynar, Esengül; Tapan, Mücip; Dilbas, HasanTürkiye aktif bir deprem kuşağı bölgesinde yer almaktadır ve günümüze kadar birçok deprem geçirmiştir. Bunun sonuçlarını hem maddi hem manevi olarak ağır ödemiştir. Türkiye'de gün geçtikçe artan nüfus ile birlikte mevcut yapı stoğu artmaktadır. Ortaya birçok plansız yapılaşma ve kontrolsüz konutlar çıkmıştır. Yaklaşık son 30 yıldır bu plansız yapılaşma ve kontrolsüzlükle birlikte ortaya çıkan yapıların güçlendirmesi kavramı dünyadaki mühendislik uygulamalarına taşınmıştır. Ülkemiz, son yıllarda 1998 Adana-Ceyhan depremi, 1999 Düzce depremi, 2011 Van depremi ve en yakın tarihte 2023 Kahramanmaraş depremleri ile çok şiddetli sarsılmıştır. Bugüne kadar birçok deprem olmuş ve ardından yönetmelikler güncellenerek yenileri çıkarılmıştır. 1940 yılından bugüne kadar 7 adet deprem yönetmeliği yayınlanmıştır. Son yıllarda gelişen teknoloji ve ihtiyaçlar doğrultusunda yönetmelikler çağa uygun revize edilmiş, kullanılan malzeme çeşitliliği ve yapı modelleri artmıştır. Betonarme yapı elemanlarında onarma-güçlendirme ya da yapının iyileştirilmesi için farklı yöntemler veya malzemeler tercih edilmektedir. Bu malzemelerden Lif Takviyeli Polimerler (LP), betonarme yapı elemanlarının güçlendirilmesinde kullanılmaktadır. Geleneksel güçlendirme yöntemlerine göre daha hızlı ve kolay uygulanabilen hafif bir malzeme ve yüksek mukavemete sahip olması nedeniyle LP iyi bir seçenek olarak karşımıza çıkmaktadır. Bu çalışmada, karbon esaslı lifli polimerle (CFRP) güçlendirilmiş farklı kesitlerdeki dairesel, dikdörtgen ve kare beton numunelerin literatürde yer alan deneysel verileri kullanılarak yanal kuşatma katsayıları yapay zekâ yöntemleri ile modellenmiştir. MATLAB yazılım programı kullanılarak yapay sinir ağları ve bulanık mantık yöntemleri ile litertürden elde edilen deneysel veriler modellenmiş ve farklı kesitlerdeki numunelerin yapay zekâ modelleri optimize edilerek numune yanal kuşatma katsayısı tahminleri gerçekleştirilmiştir.Article An Experimental Investigation on Fracture Parameters of Recycled Aggregate Concrete With Optimized Ball Milling Method(Elsevier Sci Ltd, 2020) Dilbas, Hasan; Cakir, Ozgur; Yildirim, HasanIn this paper, Ball Milling Method (BMM) is employed on recycled aggregate (RA) with an optimization process which is conducted to enhance RA efficiently eliminating attached old mortar (AOM) content in RA. Various combinations of drum rotation (R) (100-200-300-400-500) and the steel balls (S) (0-2-5-7-10-12) applied to the recycled aggregate during the BMM process and treated recycled aggregates (RAi) are obtained. The mechanical properties (compressive, splitting tensile and flexural strength values and elasticity modulus) and the non-linear fracture parameters (effective crack length, crack mouth opening displacement, crack tip opening displacement, initial cracking toughness, unstable fracture toughness and fracture energy) of concretes including untreated and treated recycled aggregate (RAi) are determined. The test results proved that the water absorption values of recycled aggregates in the size of 4-11.2 mm and 11.2-22.4 mm reduced from 8.80% to 1.40% and 8.95% to 0.84%, respectively, after treatment process. It is also found that the compressive strength of concretes are marginally affected with the use of treated recycled aggregate (RAi) up to 60% which is twofold of the optimum recycled aggregate proportion given in the literature. Moreover, 60% RAi content in concrete can be recommended in terms of fracture characteristics (a(c), CMODc, CTODc, K-ic(ini), K-ic(un) and G(F)). (C) 2020 Elsevier Ltd. All rights reserved.Article Influence of Basalt Fiber on Physical and Mechanical Properties of Treated Recycled Aggregate Concrete(Elsevier Sci Ltd, 2020) Dilbas, Hasan; Cakir, OzgurThis paper investigates the effect of the treatment methods on the physical and the mechanical properties of recycled aggregate concrete (RAC). The optimized Ball Mill Method (oBMM) and the incorporation of basalt fiber (BF) in concrete were employed as treatment process and the combination of oBMM and BF were utilized in this experimental study. It was intended using the treatment methods that the application of oBMM on recycled aggregate (RA) cleaned the most part of attached old mortar (AOM) content in RA and the incorporation of BF in concrete eliminated the adverse effects of remaining AOM in treated RA (tRA) strengthening mortar phase of concrete. Hence, to observe the improvement impact of treatment on the performance of concretes, twenty-eight concrete series including natural aggregate (NA), 20-40-60% RA and 20-40-60% tRA with 0-0.25-0.50-1.0% BF were produced in the laboratory. The physical and the mechanical tests were conducted on concrete specimens at the age of 28 days. According to the test results, although the physical properties were negatively affected by the incorporation of RA and tRA with/without BF in concrete, the mechanical properties of RACs and tRACs were improved by the incorporation of BF. Besides, the impact of treatment were significantly observed, especially for higher rates of RA (60%). The optimum proportion of BF was found as 0.50% BF with 60% tRA regarding compressive strength test results only. (C) 2020 Elsevier Ltd. All rights reserved.Article An Investigation on Physical, Mechanical and Microstructural Properties of Electricity-Based Cured Gbfs-Fa Geopolymer(Elsevier Sci Ltd, 2025) Aygun, Beyza Fahriye; Uysal, Mucteba; Bilir, Turhan; Cosgun, Turgay; Dilbas, HasanThis paper aimed to investigate and develop curing process of geopolymer as a building material of the future. As well-known, the geopolymer may require heat while hardening and gaining strength. Application of heat treatment to the geopolymer on-site with heat sources are solutions, but it can be said that it is one of the most difficult processes of geopolymer. Thus, on-site electricity curing has been developed to overcome the difficulties in geopolymer curing. The developed curing process depended on application of AC voltage (10 V, 20 V, and 30 V) and the electrical resistance of geopolymer ensured a heat on geopolymer while curing process. In this experimental study, different NaOH and different GBFS/FA ratios were employed to seek the best solution. Also, the electrical resistance/conductivity of geopolymer was regulated with the addition of carbon fiber (CF), steel fiber (ST), waste wire erosion (WWE) (0.25 %, 0.50 %, and 0.75 %), and carbon black (CB) (1 %, 2 % and 3 %). Compressive strength (CS), flexural strength (FS), ultrasound pulse velocity (UPV), water absorption, void ratio, and unit weight were investigated parameters of geopolymer and were used to determine the best geopolymer mixtures. The internal and surface temperatures of geopolymer can be regulated by electricity-based thermal curing and it ensured a capability to set the optimum temperature on geopolymer. 20 V applications had the best efficiency in activating the geopolymerization reaction and the compressive strength positively affected, resulting the highest compressive strength as 78.02 MPa for SFA05WWE. Electricity-based thermal curing had a significant potential to surpass on-field-challenges in curing process of geopolymer and to obtain desired strength grade in not only indoor but also outdoor engineering applications.Master Thesis Laboratory Waste Concrete, Waste Marble Powder, Pumice Powder, and Super Absorbent Polymer-Based Sustainable Engineering Characteristics Enhanced Composite (ecc): Physical, Mechanical, and Microstructural Properties(2024) Ataman, Jinda; Dilbas, HasanBeton, yapıların vazgeçilmez bir malzemesi halini almıştır. Fakat betonun doğaya olan zararları düşünülürse; bünyesinde bağlayıcı malzeme olarak bulunan çimentonun üretimi esnasında atmosfere karbon salınımı giderek artmaktadır. Mevcut yapı stoklarının kentsel dönüşüm adı altında yıkılması ve bu oluşan atık yapı ürünlerinin doğaya verdiği zarar bilinmektedir. Bu gibi durumların çevreye verdiği zarar düşünülerek yeşil, çevreci, akıllı ve sürdürülebilir bir yapı malzemesi üretilmesi hedeflenmektedir. Oluşturulacak yapı malzemesinin çevreci, sürdürülebilir, yeşil olması için; mermer tozu, geri kazanılmış agrega tozu ve pomza tozu ile sağlanacaktır. Akıllı bir yapı malzemesi olması için ise kullanılacak mineral katkıların beton bünyesinde tam aktifleşebilmesi ve içsel bir kürleme yapabilmesi amacıyla malzeme matrisine süper absorban polimer katılacaktır. Süper absorban polimer sayesinde oluşturulacak ürün hidratasyon için gerekli olan suyu yavaşça harç matrisine salarak hidratasyonu kontrol altına alacaktır. Bu sayede ürünün gerekli mühendislik özelliklerini daha iyi karşılaması beklenecektir. Ürünün bünyesinde fiber kullanılacaktır. Bu sayede yapı malzemesi basınç dayanımının yanında eğilme, çekme dayanımı da ön plana çıkacaktır. Üretilecek yapı malzemesinin sürdürülebilir, yeşil ve akıllı olması açısından ve gerekli mühendislik özellikleri karşılaması ile üretime geçilecek ve mevcut yapı stokunda kullanımı teşvik edilecektir. Bununla beraber mevcut yapı stoku doğa dostu, geri dönüşüme müsait bir hal alacaktır. Sonuç olarak dünyaya betonarme yapıların verdiği zarar giderek azaltılabilecek ve yapıların doğaya dönüşü sağlanacaktır. Bu tez ile 'Cumhurbaşkanlığı Türkiye Yüzyılı Vizyonu' kapsamında yer alan aşağıdaki hedeflere katkıda bulunulacaktır. 1. Cumhurbaşkanlığı Türkiye Yüzyılı Vizyonu'nda olan 'Sıfır Atık Projesi' 2. Cumhurbaşkanlığı Türkiye Yüzyılı Vizyonu'nda olan 'Sanayide Yeşil Dönüşüm Projesi'.Article Mechanical Performance Improvement of Super Absorbent Polymer-Modified Concrete(Elsevier, 2023) Dilbas, Hasan; Birdal, Furkan; Parim, Co Kun; Gunes, Mehmet amilIn this study, a method has been developed to reduce the negative effects of superabsorbent poly-mers on concrete mechanical properties. The method involves concrete mixing and curing, with the concrete mixture being designed using a decision tree algorithm. Instead of the standard wa-ter curing approach, air curing conditions were used during the curing process. In addition, heat treatment was applied to reduce any possible negative effects of the polymers on the concrete's mechanical properties and to enhance their performance. The details of all these stages are pre-sented in this method. Various experimental studies were conducted to demonstrate the validity of this method, which proved to be effective in reducing the negative effects of superabsorbent polymers on concrete mechanical properties.center dot The method can be used to eliminate the negative effects of superabsorbent polymers.center dot The proposed method yielded promising results, demonstrating that the expected level of compressive strength, modulus of elasticity and toughness in concrete can be achieved in 5-10 days instead of 28 days center dot The widespread use of superabsorbent polymers in the concrete industry and reinforced con-crete systems can be attributed to their many benefits.Article 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, OrhanSustainability 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.Article Mineral Addition and Mixing Methods Effect on Recycled Aggregate Concrete(Mdpi, 2021) Dilbas, Hasan; Gunes, Mehmet SamilThis paper presents influence of treatment and mixing methods on recycled aggregate concretes (RAC) designed regarding various techniques. Absolute Volume Method (AVM) according to TS 802, Equivalent Mortar Volume Method (EMV), silica fume (SF) as a mineral addition were considered in the design of concretes. In total, four groups of concretes were produced in the laboratory: (1) natural aggregate concrete (NAC) designed with AVM as control concrete, (2) RAC designed with AVM as control RAC, (3) RAC with SF as a mineral addition designed with AVM as treated RAC and (4) RAC designed with EMV as treated RAC. The tests were performed at 28th days and the statistical analysis were made on the test results. According to the results, EMV and SF increased the compressive strength of concretes and this resulted an increase in the strength class of concrete. A significant statistical difference between the concretes were determined. According to multiple comparison analysis, it was found that especially there was a significant relationship among NAC, RAC and RAC-EMV. In addition, it was recommended that EMV and AVM with 5% SF could be used in the design of RAC rather than AVM only to achieve the target strength class C30/37.Article 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, HasanIn 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.Article Optimization of Synthetic Fiber-Reinforced Calcined Bentonite-Based Recycled Aggregate Geopolymer Composites Based on Multicriteria Decision Support Method(Asce-Amer Soc Civil Engineers, 2025) Sahin, Furkan; Aladag, Cenk; Uysal, Mucteba; Dilbas, Hasan; Bendjilali, Fatiha; Ayguen, Beyza FahriyeThe study evaluated the mechanical and durability properties of synthetic fiber-reinforced, metabentonite (MB)-based geopolymer composites (GCs) using 50x50x50-mm cubes for compressive strength and 40x40x160-mm prisms for flexural strength, according to standards for density and void analysis, direct tensile strength, and splitting tensile strength. Durability assessments included abrasion resistance and high-temperature effects, with the latter potentially adhering to standards for fire resistance tests of construction materials. First, a preliminary study was adopted on the calcination of bentonite, which was carried out at 900 degrees C. GCs were prepared in various MB/ground granulated blast furnace slag (GBFS) ratios (25%, 50%, 75%, and 100%) with molar concentrations (8M, 10M, 12M, and 14M) and 2:1 Na2SiO3/NaOH. Synthetic fiber reinforcement such as polypropylene fiber (PPF) polyamide fiber (PAF), and basalt fiber (BF) with 0.5%, 1%, 1.5%, and 2% consumption ratios were employed for the mixtures of GCs. This comprehensive study followed a series of steps. The first step depended on determining the mechanical behavior. The second step included the durability behavior of the best GCs for each fiber type inclusion. The best solution chosen/mixture optimization of GCs step depended on a multicriteria decision-making method and a capable method (TOPSIS-Technique for Order of Preference by Similarity to Ideal Solution) to evaluate the results. Accordingly, the best GCs were obtained, and the durability index of the best GC was determined. The GCs were subjected to high temperatures of 200 degrees C, 400 degrees C, 600 degrees C, and 800 degrees C, and the results showed that optimal GCs based on TOPSIS-multicriteria decision support method have 1% PPF, 0.5% PAF, and 0.5% BF fiber content. The BF-containing series showed the best performance among the fiber types. The offered GCs were the possible net-zero/low-carbon materials for future cities.Article Optimizing the Treatment of Recycled Aggregate (>4 Mm), Artificial Intelligence and Analytical Approaches(Mdpi, 2023) Dilbas, HasanAttached, old mortar removal methods are evolving to improve recycled aggregate quality. Despite the improved quality of recycled aggregate, treatment of recycled aggregate at the required level cannot be obtained and predicted well. In the present study, an analytical approach was developed and proposed to use the Ball Mill Method smartly. As a result, more interesting and unique results were found. One of the interesting results was the abrasion coefficient which was composed according to experimental test results; and the Abrasion Coefficient enables quick decision-making to get the best results for recycled aggregate before the Ball mill method application on recycled aggregate. The proposed approach provided an adjustment in water absorption of recycled aggregate, and the required reduction level in water absorption of recycled aggregate was easily achieved by accurately composing Ball Mill Method combinations (drum rotation-steel ball). In addition, artificial neural network models were built for the Ball Mill Method The artificial neural network input parameters were Ball Mill Method drum rotations, steel ball numbers and/or Abrasion Coefficient, and the output parameter was the water absorption of recycled aggregate. Training and testing processes were conducted using the Ball Mill Method results, and the results were compared with test data. Eventually, the developed approach gave the Ball Mill Method more ability and more effectiveness. Also, the predicted results of the proposed Abrasion Coefficient were found close to the experimental and literature data. Besides, an artificial neural network was found to be a useful tool for the prediction of water absorption of processed recycled aggregate.Article Physical and Mechanical Properties of Treated Recycled Aggregate Concretes: Combination of Mechanical Treatment and Silica Fume(Asce-amer Soc Civil Engineers, 2021) Dilbas, Hasan; Cakir, OzgurThis paper presents the combined effect of the mechanical treatment of recycled aggregate (RA) and the use of silica fume (SF) in the concrete mixes. In the first step, the RA is treated by the optimized ball mill method (oBMM) to decrease mortar content. In the second step, the SF is used to enhance the negative effects of the attached old mortar (AOM) that has remained in the RA. In this method, natural aggregate (NA), RA, and treated RA (tRA) at various ratios (20%-40%-60%) with 0%-5%-10% SF are used in the mixes. After 28 days, tests are carried out on the specimens. The results show that the mechanical treatment followed by the SF combination significantly enhances the performance of recycled aggregate concretes (RACs). Satisfactory test results are generally obtained for treated recycled aggregate concrete (tRAC) produced with up to 60% tRA and 10% SF. This improvement can be explained as the consequence of the removal of AOM by oBMM and eliminating the adverse effects of the remaining part of AOM in tRA by SF addition in concrete.Master Thesis Physical, Mechanical, and Microstructural Properties of a Sustainably Engineered Composite (ecc) Based on Demolition Waste, Waste Marble Powder, Pumice Powder and Superabsorbent Polymer(2024) Nergis, Alican; Dilbas, HasanBeton, modern yapıların inşasında yaygın olarak kullanılan ana yapı malzemesidir. Ancak, betonun ana bileşen maddesi olan çimentonun üretimi sırasında atmosfere yüksek miktarda karbon salınımı gibi çevresel etkileri mevcuttur. Ayrıca, mevcut yapı stoklarının yıkılmasıyla ortaya çıkan atık malzemeler de çevre için ciddi bir sorun teşkil etmektedir. Bu nedenle, çevresel etkileri azaltmak amacıyla yeşil, çevreci, akıllı ve sürdürülebilir bir yapı malzemesinin geliştirilmesi gerekmektedir. Bu çalışmada, çevreci, sürdürülebilir ve akıllı bir yapı malzemesi oluşturulması hedeflenmektedir. Bu amaçla, mermer tozu, geri kazanılmış agrega tozu ve pomza tozu gibi atık, temini ve kullanımı daha kolay malzemeler kullanılacaktır. Ayrıca, yapı malzemesinin akıllı özellikler kazanması için mineral katkılar ve süper absorban polimerler gibi özel bileşenler kullanılacaktır. Süper absorban polimerler, malzemenin hidratasyon sürecini kontrol ederek mühendislik özelliklerini optimize edecek ve suyun önce emilimi daha sonra yavaş yavaş salınımına sebep olarak içsel kürleme sağlayacaktır. Fiber takviyesi ise malzemenin dayanıklılığını artıracak ve daha yüksek mühendislik özellikleri sağlayacaktır. Geliştirilecek bu yapı malzemesinin sürdürülebilir, yeşil ve akıllı olmasıyla birlikte, ilerleyen zamanlarda patentleşmiş bir ürün olarak üretime geçilmesi planlanmaktadır. Mevcut yapı stokunda bu malzemenin kullanımı teşvik edilerek, çevresel etkileri azaltılmış ve geri dönüşüme uygun bir yapı stoku oluşturulması amaçlanmaktadır. İlk aşamanın sonuçlarına göre, 35, 49 ve 60. Çalışma en yüksek üç numune olarak belirlendi. Ardından ikinci aşamada, bahsi geçen numuneler doğrulandı ve 35. numune hem önceki hem de sonraki beton atıkları dikkate alındığında en iyi sonuçları verdi: sırasıyla 56.66 MPa basınç dayanımı ile en iyi sürdürülebilir ECC karışımının (Numune 35) birçok mühendislik alanı açısından geliştirmeye açık yönlerinin olduğunu göstermektedir. Bu proje, 'Cumhurbaşkanlığı Türkiye Yüzyılı Vizyonu' kapsamında belirlenen hedeflere katkıda bulunmayı amaçlamaktadır. Özellikle 'Sıfır Atık Projesi' ve 'Sanayide Yeşil Dönüşüm Projesi' gibi hedeflerin gerçekleştirilmesine destek olacak bir adım olarak değerlendirilmektedir.