Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleAçık Erişim2025Alkali Aktifleştirilmiş Uçucu Kül ve Polipropilen Elyaf Ile Iyileştirilmiş Yüksek Plastisiteli Siltli Zeminin Durabilite Performansının Incelenmesi
Kamiloğlu, Hakan Alper; Kurucu, Kutluhan; Durak, Muhammet Oğuz
Bu çalışmada aktivatör içeriği, fiber takviye türü ve fiber içeriği gibi parametrelerin durabilite özellikleri üzerindeki etkileri araştırılmaktadır. Geleneksel yöntemler durabilite değerlendirmesi için genellikle ıslatma-kurutma veya donma-çözülme döngülerine odaklanırken, bu çalışma saha koşullarını daha doğru bir şekilde simüle eden ıslatma testlerinin önemini vurgulamaktadır. Zemin iyileştirme uygulamalarında, malzemenin kırılganlığı hem geleneksel hem de alkali ile aktive edilen bağlayıcıların kullanımı ile artmaktadır. Lif takviyesi, bu sorunu çözmek ve sünekliği artırmak için yaygın bir uygulamadır. Bu çalışma, çeşitli lif türlerini ve bunların zemin özelliklerinin farklı yönlerini iyileştirmedeki rollerini incelemektedir. Özellikle, farklı tip ve uzunlukları bir araya getiren hibrit liflerin kullanımı, zemin tabakalarının durabilite özelliklerini artırma potansiyeli açısından araştırılmıştır. Çalışmanın deneysel kısmı, lif takviyesi ve alkali ile aktive edilmiş uçucu kül ile stabilize edilmiş yüksek plastisiteli siltli zeminin ıslatma etkilerine karşı davranışını araştırmaktadır. Çalışma, Na2SiO3/NaOH oranının, 3 mm ve 12 mm uzunluğundaki lif içeriğinin ve bu lif uzunluklarının kombinasyonlarının bozulma, serbest basınç dayanımı (UCS) ve ıslatılmış numunelerin dayanım azalması üzerindeki etkilerini ele almaktadır. Numunelerin dayanıklılık performansı çeşitli ıslatma süreleri ile değerlendirilmiştir. Sonuçlar, farklı uzunluklarda karıştırılan hibrit liflerin kullanımının, stabilize edilmiş zeminin durabilite özelliklerini iyileştirmede dikkate değer katkı sunduğu belirlenmiştir.
- MakaleAçık Erişim2025Optimization 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.
- MakaleAçık Erişim2024Optimization Of Cantilever Retaining Wall Design Using Improved Teaching-Learning-Based Optimization Algorithms
Tayfur, Bilal; Kamiloğlu, Hakan Alper
Retaining structures play a crucial role in geotechnical engineering to support soil levels, prevent slope failure, and create flat surfaces for construction. Designing these structures involves optimizing internal and external stability while minimizing material usage and cost. This study focused on optimizing reinforced concrete cantilever retaining walls using the Teaching-Learning Based Optimization (TLBO) algorithm and an improved version (I-TLBO) with agents. In the context of the study, geometric-structural design variables, geotechnical -structural constraints, and optimization processes were examined. Minimizing weight and minimizing cost of the wall were the objectives considered in the cantilever retaining wall design process. The optimization results were compared with other algorithms in the literature, such as genetic algorithms, evolutionary strategies, and particle swarm optimization. The improved TLBO algorithm demonstrated superior performance, achieved lower design dimensions, and reduced costs. It provided more efficient solutions that pushed design constraints closer to their limits, resulting in a cost-effective and structurally sound cantilever retaining wall design. As a result of the study, the I-TLBO algorithm was found to be more cost and weight-effective than other methods in the optimization of cantilever retaining wall design.
AtıfOpenAlex2TR Dizin2
İncele - MakaleYalnız künye2024Scopus SJRQ2Optimization, 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.
AtıfScopus6OpenAlex6
İncele - MakaleAçık Erişim2023Scopus SJRQ2Optimizing 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.
AtıfScopus6WoS4OpenAlex8
İncele - MakaleAçık Erişim2019Farklı İstinat Duvar Tiplerinde Aktif Toprak Basınçlarının Sayısal Analizi
Sadoglu, Erol; Yılmaz, Mehmet Fatih; Kamiloğlu, Hakan Alper
Dayanma yapılarının tasarımında yatay toprak basıncı dağılımı önem arz etmektedir. Birçok çalışmada, dayanma yapısına etkiyen aktif toprak basınç dağılımı nonlineer olarak kabul edilir. Toprak basınç dağılışı ile ilgili çok sayıda çalışma olmasına karşın, Duvar boyutlarının yatay toprak basıncı dağılışı üzerine etkilerini irdeleyen az sayıda çalışma bulunmaktadır. Bu çalışmada, duvar şeklinin aktif yanal toprak basınç dağılımı ve aktif kırılma yüzeyleri üzerine etkisi incelenmiştir. Bu nedenle çeşitli tip dayanma duvarlarına gelen yanal toprak basınç dağılışları ve oluşturdukları kırılma yüzeyleri numerik olarak irdelenmiştir. Yapılan çalışma kapsamında, çeşitli eğimlerdeki ağırlık tipi dayanma duvarları, farklı topuk uzunlukları ve eğime sahip ters T biçimli dayanma duvarları göz önüne alınmıştır. Yapılan çalışma sonucunda yanal toprak basınç dağılışının duvar tipine göre değiştiği belirlenmiştir. Buna ek olarak duvar eğimi ve topuk uzunluğunun kırılma yüzeyleri ve yanal toprak basınç dağılışı üzerinde etkili olduğu görülmüştür.
AtıfTR Dizin1İncele - MakaleAçık Erişim2019Scopus SJRQ1A method for active seismic earth thrusts of granular backfill acting on cantilever retaining walls
Kamiloğlu, Hakan Alper; Şadoğlu, Erol
The failure mechanism plays an important role in the active seismic earth thrusts acting on cantilever retaining walls. Cantilever retaining walls can be classified as having a long heel or a short heel based on the intersection between the stem of the retaining wall and the failure surface. In the literature, different seismic earth thrust calculation methods have been suggested considering the long heel or the short heel cases. However, no unique study has been done that is applicable to walls with either a long heel or a short heel. The aim of this study is to suggest a new active seismic earth thrust calculation method for granular soils which is applicable to retaining walls with either a short heel or a long heel using a pseudo-static approach. Three different earth thrusts are considered to be acting on three different parts of a wall backface. Each thrust is derived in terms of the parameters defining the wall geometry, the soil properties and the seismic activity. The thrust coefficients are determined by maximizing the sum of the horizontal components of the earth thrusts. An algorithm is developed and coded for this aim. The results of the suggested method are compared with those of other conventional methods and an experimental study.
AtıfScopus16WoS11OpenAlex18İncele