Sürdürülebilir Kentsel Altyapı Mühendisliği Ana Bilim Dalı Tez Koleksiyonu
https://hdl.handle.net/20.500.12573/424
2024-03-28T18:23:10ZThe use of waste plastics in asphalt mixtures
https://hdl.handle.net/20.500.12573/1436
The use of waste plastics in asphalt mixtures
Şaka, Şükrü
Within the scope of this study, the use of waste plastics in asphalt mixtures for surface
layer of pavements was evaluated considering the specification limits in the Highways
Technical Specifications of Turkiye General Directorate of Higways. Waste plastic data
collected in Talas region has been used, a circular economy model has been created and
its contributions have been evaluated. Polyethylene type of waste plastics as high and low
density were used to replace bitumen in hot asphalt mixtures with 7.5 to 12.5% by weight
of bitumen. The optimum binder content currently used by the Talas municipality was
kept constant as (5%). In the context of Highways Technical Specifications, Marshall
stability and flow values of the mixtures with and without waste plastics were determined
and 10% replacement level were selected to use for further testing due its maximum
stability and proper flow value (2-4 mm). Air voids, voids filled with bitumen, voids in
mineral aggregates parameters on asphalt mixtures as well as softening point and flash
point of bituminous binders were also determined. In addition, environmental impacts of
asphalt mixtures with and without waste plastic replacement were examined via life cycle
assessment methodology in the scope of cradle-to-gate.10% replacement of bitumen with
waste plastics increased stability, air voids, voids in mineral aggregates and decreased
flow and void filled with bitumen of asphalt mixtures as compared with the control.
Softening point and flash point of bitumen increased with waste plastic replacement.
Considering the environmental impact of with and without waste plastic replacement
asphalt mixtures, abiotic depletion, ozone layer depletion, terrestrial ecotoxicity, and
eutrophication values increased. Abiotic depletion (fossil fuels), global warming,
freshwater aquatic, marine aquatic ecotoxicity, photochemical oxidation, acidification,
and human toxicity values decreased. The cost of waste plastic replacement asphalt
mixtures can reduce the costs of production, and laying costs.; Bu çalışma kapsamında, Türkiye Karayolları Genel Müdürlüğü Karayolları Teknik
Şartnamesi'nde yer alan spesifikasyon limitleri dikkate alınarak atık plastiklerin asfalt
karışımlarında aşınma tabakası içerisinde kullanımı değerlendirilmiştir.Talas bölgesinde
toplanan atık plastik verileri kullanılmış olup, döngüsel ekonomi modeli oluşturulmuş ve
katkıları değerlendirilmiştir. Bitüm ağırlığının %7,5 ve %12,5 oranları arasında plastik
ikamesi ile bitümün yerine yüksek ve düşük yoğunluklu polietilen türü atık plastikler
kullanılmıştır. Halihazırda Talas belediyesi tarafından kullanılan optimum bağlayıcı
içeriği (%5) olarak sabit tutulmuştur.Teknik şartname kapsamında atık plastik içeren ve
içermeyen karışımların Marshall stabilitesi ve akma değerleri belirlenmiştir. Maksimum
stabilite ve uygun akış değeri (2-4 mm) nedeniyle testler için %10 ikame seviyesi
seçilmiştir. Asfalt karışımlarda stabilite, akma, hava boşlukları, bitümle dolu boşluklar,
mineral agregalar arası boşluklar gibi parametrelerinin yanı sıra bitümlü bağlayıcıların
yumuşama ve parlama noktaları da incelenmiştir. Beşikten-kapıya yaşam döngü
değerlendirmesi ile atık plastik ikameli ve plastiksiz asfalt karışımlarının çevresel etkileri
karşılaştırılmıştır. Bitümün atık plastiklerle %10 oranında değiştirilmesi, kontrol
numunesi ile karşılaştırıldığında, plastik ikameli asfaltların stabilitesini, hava
boşluklarını, mineral agregalar arasındaki boşlukları arttırmış, akma ve bitümle dolu
boşlukları azaltmıştır. Atık plastik ikamesi ile bitümün yumuşama ve parlama noktası
artmıştır. İkameli ve plastiksiz asfalt karışımlarının çevresel etkileri karşılaştırıldığında,
abiyotik tükenme, ozon tabakası incelmesi, karasal ekotoksisite ve ötrofikasyon değerleri
artmıştır. Abiyotik tükenme(fosil yakıtlar), küresel ısınma, tatlı su-sucul, deniz-sucul
ekotoksisite, fotokimyasal oksidasyon, asitlenme ve insan toksisite değerleri azalmıştır.
Atık plastik ikamesi ile asfalt karışımlarının üretim ve serim maliyetleri azaltılabilir.
2022-01-01T00:00:00ZA life cycle approach for sustainable and energy efficient urban transport
https://hdl.handle.net/20.500.12573/1353
A life cycle approach for sustainable and energy efficient urban transport
Gülçimen, Sedat
The objective of this thesis study is to evaluate the sustainability of the urban transport system in Kayseri. In the first part, a life cycle sustainability assessment (LCSA) of the tramway system was performed using a cradle‐to‐grave approach by integrating the environmental, economic, and social aspects for the case of Kayseri, Turkey. The LCSA results revealed that the operation and maintenance phase were determined as the main contributor to the environmental load of the tramway system within its entire life cycle. For economic assessment, the main contributor to the total life cycle cost was energy cost. In the social performance evaluation, it is found that the industry performs well for society, the local community, and workers but has a weaker social performance for the consumer due to a weak feedback mechanism. In the second part, urban transport alternatives were evaluated with the integration of Hesitant Fuzzy Analytical Hierarchy Process (HF-AHP) and Multiple Attribute Utility Models (MAUT) methods. Eight sustainable transport indicators were selected and the weights of selected indicators are calculated with the utilization of HF-AHP. Based on HF-AHP results, the number of fatalities/injuries has been determined as the most significant indicator among the eight indicators with 0.158 normalized weight. Then, twelve urban transport alternatives were ranked by using the MAUT method to decide the most sustainable urban transport alternative. The results of this integrated methodology present that alternative 11, which is dominated by low-motorized vehicles, has been determined as the best sustainable alternative and alternative 1 is the worst sustainable alternative which is dominated by high-motorized vehicles with 0.69 and 0.27 of total utility values, respectively.
2021-01-01T00:00:00ZHumic acid-based superplasticizer for sustainable concrete
https://hdl.handle.net/20.500.12573/334
Humic acid-based superplasticizer for sustainable concrete
ÖZUZUN, SÜMEYYE
Superplasticizers are polymeric agents that improve the workability of fresh concrete and improve the mechanical properties of hardened concrete by reducing the required amount of water in the mixtures. Commonly used superplasticizers are not regarded as ecoefficient products due to their high energy consumption and high cost of raw material used in the production. There are studies in the literature on the use of humic acid as a dispersant, acting as a superplasticizer and created an intermolecular separating force by electrostatic repulsion and steric hindrance. However, the published literature is lack of studies on the use of humic acid as a superplasticizer in cementitious systems. The aim of this study is to investigate the plasticizing efficiency of a commercially available humic acid (HA) based solution, which is actually obtained from leonardite for agricultural use, in cementitious systems as well its effects on hydration and mechanical properties of the systems at various dosages. HA based solution was evaluated comparatively with respect to lignin based and naphthalene-based superplasticizers. HA based solution showed a plasticizing efficiency similar to lignin and the naphthalenebased product. The results suggest that humic acid-based agents should be considered as eco-efficient superplasticizers due to the similar performance on workability, hydration kinetics and mechanical properties of cementitious systems when compared to naphthalene-based superplasticizer
2019-01-01T00:00:00ZCalcined clays as supplementary cementing materials for sustainable concrete
https://hdl.handle.net/20.500.12573/325
Calcined clays as supplementary cementing materials for sustainable concrete
ARGIN, GİZEM
The Portland cement, which is used as a binder material in concrete, has an important share for CO2 emission worldwide. For this purpose, supplementary cementing materials are used to be substituted with Portland cement in specific amounts. The usage of industrial by-products such as fly ash, silica fume, and slag as supplementary cementing materials seems advantageous. However, potential in availability of good quality by-products in a local scale have led to the search for feasible alternatives to these materials. The aim of this study is to evaluate the clay samples obtained from two different deposits in Turkey after calcination in terms of their use as supplementary cementing material. Chemical, mineralogical and thermal characterization of clay samples were made before and after calcination at various temperatures. Pozzolanic activity and reaction kinetics of the clay samples were evaluated with and without limestone addition by thermal analysis and isothermal calorimetry, respectively. Water requirement and strength activity index of calcined clays selected depending on their pozzolanic activity were also determined. The pozzolanic activity of clay containing a relatively higher amount of kaolinite mineral was determined to be higher. Clays calcined at 700 ºC showed the highest pozzolanic and strength activity whereas a calcination temperature of 1100 ºC results in a relatively lower activity. The limestone addition improved the pozzolanic activity, and the heat evolution during hydration. As BET surface area increased, the water requirement for calcined clay also increased.
2019-01-01T00:00:00Z