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Sürdürülebilir Kalkınma Amaçları

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• MakaleAçık Erişim2025/r/bayburt/15944
  Optimization and Mechanical Performance of Alkali-Activated Bottom Ash and Polypropylene Fiber in Deep Mixing Columns

  Yilmaz, Fatih; Kamiloğlu, Hakan Alper; Avlayan, Büşra

  Deep mixing columns (DMC) are one of the widely used soil improvement methods in cohesive and cohesionless soils. Cement and lime are predominantly used as conventional binders in DMC grout. Due to high CO2 emissions from conventional binders, the feasibility of using alkali-activated binders as DMC grout is being investigated. This study was conducted in three main stages. In the first stage, the proportions of bottom ash and activator (mixture of 10M NaOH and Na2SiO3) were optimized to achieve the highest UCS value using response surface methodology (RSM). In the second stage, the influence of polypropylene fiber content was examined in detail by incorporating varying amounts of fibers into the optimized binder-activator mixture to determine the optimal fiber content. Since DMC are fully buried, they are cured in the soil media. In this case, the soil temperature, which varies along the depth of the soil, also becomes the curing temperature of the DCM. Due to climate, soil condition and thermodynamic based parameters, curing temperature of the DMC varies throughout the soil depth. Therefore, in the third stage, the effect of curing temperature on the mechanical properties of the stabilized samples was evaluated under different temperatures. Results of the study revealed optimal UCS values with AAB content of 0.3-0.5 and activator content of 0.45-0.5. Polypropylene fiber reinforcement further improved strength, reaching an optimum at 1.50-1.75% content. Curing temperature played a significant role, with UCS and modulus of elasticity increasing up to 30 °C, indicating the importance of considering environmental factors in DMC design. These findings suggest that the optimized mixture has the potential to replace conventional cement-based binders in DMCs, offering a more sustainable solution with lower carbon emissions. Furthermore, the observed influence of curing temperature highlights the need to account for subsurface thermal variations when designing DMCs, as these factors significantly affect strength gain and long-term performance.

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  İncele
• MakaleYalnız künye2024Scopus SJRQ2/r/bayburt/12860
  Optimization, Characterization, and Carbon Footprint Analysis of Alkali Activated Waste Tuff and Fly Ash Mixtures for Deep Mixed Columns

  Kamiloğlu, Hakan Alper; Yilmaz, Fatih

  Deep soil mixing (DSM) applications are one of the widely known soil stabilization techniques which can be applied to a wide range of soil types. Cement and lime are the major materials used as binders for DSM applications. However, as conventional binders lead to emit a large amount of CO2 during production, eco-friendly binders suitable for DSM applications have become prominent. Alkali-activated materials are good alternatives to conventional binders. This study was intended to investigate the usability of zeolite rich tuff wastes as an alkali-activated binder in DSM columns. Within this scope, the waste tuff and C-type fly ash mixture were used as an alkali-activated binder, and 10 M NaOH solution was used as an activator. Response surface methodology (RSM) was employed in experimental design to determine optimum components to obtain maximum unconfined compression strength and investigate the interaction between stabilization agents. From the RSM analysis the optimum ratios of activator (X1), waste tuff (X2), and precursor (X3) were determined as; X1 = 0.251, X2 = 0.548, and X3 = 0.538 for maximum UCS. UCS, mineralogical and microstructural characterization (XRF, XRD, SEM, EDX, FTIR) was performed for the DSM samples prepared considering the optimized components. It was determined that the UCS values of the 3, 7, and 28-day cured samples stabilized by considering the optimum values gave UCS values approximately 3 to 5 times higher than the lower limit values recommended by FHWA. As a result of mineralogical and microstructural investigation, the reason for the strength increase in the samples can be attributed to the formation of geopolymeric gel between the soil particles by tuff waste and fly ash activated with alkaline activator. Carbon footprint analyses were performed for 1m3 DSM columns produced with alkali-activated binders and ordinary Portland cement (OPC). From the analyses it was seen that the carbon footprint of the DSM column produced using alkali activated binders is lower than that of the DSM column obtained with OPC. After the general evaluation of the study, it is seen that the hypothesis that waste tuff can be used as environmentally safe alkali-activated binders instead of traditional binders is supported.

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  AtıfScopus6·OpenAlex6

  İncele
• MakaleAçık Erişim2023Scopus SJRQ2/r/bayburt/13127
  Optimizing and investigating durability performance of sandy soils stabilized with alkali activated waste tuff-fly ash mixtures

  Yilmaz, Fatih; Kuvat, Ahmet; Kamiloğlu, Hakan Alper

  The search for alternative environmentally-friendly materials to Portland cement is increasing its importance in geotechnical engineering as in other fields. In this study, alkali activated waste volcanic tuff (BT) and fly ash (FA) utilized as an alternative to conventional binders. The specific objectives of this paper were to, (1) optimize fly ash, waste tuff and activator content using Response Surface Methodology (RSM), (2) investigate the UCS performance of the optimum amount of alkali-activated fly ash and waste tuff mixtures as a binder in soil stabilization by comparing with various codes, (3) characterize the optimized parameters, (4) examine durability performances of the samples. Optimum binder and activator content and effect of waste tuff on strength characteristics were evaluated statistically with RSM approach. XRF, XRD, FTIR analyses were performed to verify the synthesized alkali activated material in the inner structures of the optimized samples. The durability and mechanical properties of samples stabilized with alkali activated binders against soaking condition, wetting-drying and were investigated. Destructive and non-destructive methods were employed to examine mechanical and durability characteristics. Unconfined compression strength, strength reduction ratio, soil deterioration, and water absorption capacity was taken into account to evaluate durability performances. UCS values of the stabilized samples were compared with limit UCS values suggested by several standards. As a result of the study it was determined that alkali activated waste tuff and fly ash mixture shows significant mechanical and durability performance in soil stabilization, and capable to use as an alternative to conventional non-green binders.

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  AtıfScopus6·WoS4·OpenAlex8

  İncele
• MakaleYalnız künye2023Scopus SJRQ1/r/bayburt/13016
  Gamma-ray and neutron shielding capability of blended cement-stabilized barite fillers developed by maximum density method

  Gökçe, H.S.; Öksüzer, N.; Kamiloğlu, H.A.; Yılmaz, F.

  The disposal of radiological wastes in the deep geological repositories has become an important issue for the reduction of hazardous risks on the human and biological environments. In this study, blended cement-stabilized barite fillers against gamma rays and neutrons have been developed with the use of the maximum density method by considering various amounts of water (100–300 kg/m3), binder (4–10%), and compaction energy (500–2000 kJ/m3). According to the experimental series of these filler materials, satisfactory response surface results have been achieved in the study. The experimental results revealed that compacted filling material can ensure an efficient shielding capability for gamma rays and neutrons when designed with a density of 3.064 g/cm3. An increase in binder content, water content, and compaction energy has improved the compressive strength of these materials up to 37 times according to that of the poorest series. Neutron and gamma-ray shielding capabilities were found to be 119 and 14% higher than those of the poorest filler material, respectively when theoretical and experimental results are considered in the study.

  AtıfScopus4·WoS3·OpenAlex5

  İncele
• MakaleAçık Erişim2023Scopus SJRQ2/r/bayburt/12900
  The Toughness of Polypropylene Fiber-Reinforced Foam Concrete under Various Uni- and Tri-Axial Compression Loads

  Gökçe, H.S.; Öksüzer, N.; Kamiloğlu, H.A.; Eyüboğlu, M.; Yılmaz, F.

  Foam concrete has recently become a key construction material in terms of meeting the special needs of modern engineering applications such as thermal insulation, absorption of static and dynamic loads. In this study, the effect of polypropylene fiber content and various uni- and tri-axial compression loads on the toughness response of polypropylene fiber-reinforced foam concrete was investigated. Up to a certain strain level (0.1 mm/mm), the ultimate compression stress of specimens under uni- and tri-axial loading increased from about 1 MPa to 16 MPa with the increased target densities of foam concrete. There was a strain-hardening capability of low-density foam concrete while the specimens failed by strain-softening in the high-density series. The optimum fiber amounts were found to be 3.9%, 4.6%, and 6.4% for low, medium, and high target densities of foam concrete, respectively. At low-density series, the bubbles were observed to be relatively bigger and mostly merged with each other. A reduction in foam content (vice versa, increasing target density of mixture) and the presence of fiber resulted in smaller pore size and a more homogenous distribution of them in the matrix. In conclusion, the desired pore structure and efficient bridging of fibers in the matrix allowed the production of favorable foam concrete with higher toughness.

  AtıfScopus14·WoS10·OpenAlex14

  İncele
• MakaleAçık Erişim2021/r/bayburt/14624
  Strength and Durability Performance of Clayey Soil Stabilized with Lime and Marble Powder

  Yilmaz, Fatih; Demir, Ersin

  This paper investigated the effect of freezing-thawing and wetting-drying cycles on the strength and durability of clay soil stabilized with lime and marble powder. The test samples were prepared by adding 5%, 10%, 15% and 20% of marble powder, without and with 6% lime to the soil which is a high plasticity clay (CH) according to the Unified Soil Classification System. Unconfined compressive strength tests were performed after 7 and 28 days of curing periods. The durability behavior of the samples was examined by applying freezing-thawing and wettingdrying cycles to the prepared samples. The results of this study show that the presence of marble powder in the soil mixture has an important role in the improvement of strength. An increase in the number of wetting-drying cycles does not decrease the volumetric stability of the samples stabilized with marble powder. The use of lime and marble powder together increased the strength values compared to the natural soil and the use of lime only. It was concluded that the co-use of lime and marble powder had a positive effect on the strength and durability behavior of high plasticity clayey soil.

  AtıfTR Dizin1

  İncele
• MakaleAçık Erişim2021Scopus SJRQ1/r/bayburt/13510
  Investigation of time-history response of a historical masonry minaret under seismic loads

  Yurdakul, Muhammet; Yılmaz, Fatih; Artar, Musa; Can, Ömer; Öner, Erdal; Daloğlu, Ayşe T.

  This study presents an investigation of the seismic performance of a historical masonry minaret which was built in the 12th century in Bayburt. The minaret was built as masonry with regional stones and handmade bricks. The most important feature of the minaret is its longitudinally conical geometry. An experimental investigation was made to obtain the mechanical properties of the regional stone used in the historical minaret. A three-dimensional Finite Element Model of the historical minaret was created in SAP2000. Three earthquake ground motions such as Erzincan, Kocaeli-Duzce, and Van-Ercis were used to investigate the seismic performance of the historical minaret. The results show that Erzincan, Kocaeli-Duzce and Van-Ercis earthquakes may cause some damages in the same zone of the minaret body since the tensile stresses occurred due to the earthquakes exceed the limit tensile stress of the masonry brick. The use of the data obtained from the experimental investigation of the Bayburt yellow stone in the analysis is important for the reliability of the results.

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  AtıfScopus44·WoS43·OpenAlex44

  İncele
• MakaleAçık Erişim2020/r/bayburt/14838
  Uçucu Kül ve Mermer Tozu Katkılarının Zeminin Stabilizasyonuna ve DonmaÇözülmesine Etkisinin Araştırılmas

  Yilmaz, Fatih

  Zemin stabilizasyonunda farklı katkı maddelerinin davranışı, uzun yıllardan beri geoteknik mühendisliğinde araştırılan bir çalışma alanıdır. Bu çalışmada uçucu kül ve mermer tozu atıkları, katı atık yönetimi kapsamında zemin stabilizasyonu için kullanılmıştır. Çalışma kapsamında, düşük plastisiteli killi bir zemine %25 uçucu kül ve sırasıyla %0, %5, %10, %15, %20 oranlarında mermer tozu ilave edilmiştir. Hazırlanan karışımların indeks ve dayanım gibi geoteknik özellikleri irdelenmiştir. Ayrıca, katkı maddelerinin zeminin donma-çözülme çevrimi sonucundaki dayanım değerlerine etkisi incelenmiştir. Çalışma sonucunda, uçucu kül+mermer tozu karışımlarının sadece uçucu kül içeren karışımlara göre daha yüksek dayanım sağladığı sonucuna varılmıştır.

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  AtıfOpenAlex5·TR Dizin4

  İncele
• MakaleAçık Erişim2020/r/bayburt/14835
  Usability of Midyat Stone Wastes in Soil Stabilization

  Yilmaz, Fatih; Duman, Vedat

  Improving the geotechnical properties of weak soils is described as soil stabilization. In this study, industrial wastes of Midyat stone were used to carry out soil stabilization. Midyat stone wastes, which are evaluated in the improvement of a low plasticity clay soil, were mixed with natural soil at 5%, 10%, 15% and 20% additive percentages. In the light of the data obtained, the presence of a different binder was needed and lime was chosen as the primary binder. Index, strength and durability tests were carried out in mixtures containing 5%, 10%, 15% and 20% Midyat stone waste with and without lime. When the results of the experiments were examined, it was determined that the use of Midyat stone waste as an additive alone was ineffective on strength and durability values. In use with lime, 49% increase in strength has been determined compared to only lime sample. As a result of the study determined that the effect of Midyat stone wastes on freezing-thawing is very limited and more effective on wetting-drying, it was concluded that these wastes can be used for stabilization of low plasticity soils with lime.

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  AtıfOpenAlex1·TR Dizin1

  İncele
• MakaleYalnız künye2020Scopus SJRQ4/r/bayburt/13514
  Effect of fineness on lime stabilization of low plasticity clays

  Yilmaz, Fatih; Kocabey, Sefa

  In this study, stabilization with lime was investigated within the scope of surface soil stabilization. The main aim of the study is to examine the grindability of the lime and investigate the effect of grinded lime on the strength and durability behavior of stabilized soil. This paper is divided into two parts. The first part deals with the grindability of the lime. The second part analyses the results of geotechnical tests with grinded and ungrinded lime. Ungrinded lime, 90% of which is below 48 microns, was reduced to less than 20 microns. The test samples were prepared by adding 2%, 4%, 6%, 8% and 10% of grinded and ungrinded lime to a low plasticity clay according to the Unified Soil Classification System. Curing times for strength tests were determined as 1, 7, 14 and 28 days. The properties of the prepared mixtures were investigated by their geotechnical properties such as index, strength and durability. In the light of the data obtained from the experiments, it is concluded that the fineness of the lime has a direct positive effect on the strength and durability characteristics.

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