Elektrik ark ocağı fırını cürufunun karayolu esnek üstyapısı aşınma tabakası için eğilme dayanımı üzerindeki etkisinin incelenmesi
Investigation of the effect of electric arc oven slag on bend resistance for highway flexible superstructure wear layer
Yazar: BURAK YAR
Danışman: DR. ÖĞR. ÜYESİ ŞÜKRÜYE İYİNAM
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / İnşaat Mühendisliği Ana Bilim Dalı / Ulaştırma Mühendisliği Bilim Dalı
Derece: Yüksek Lisans, 2019
Konu: Ulaşım = Transportation ; İnşaat Mühendisliği = Civil Engineering

Özet:
Küresel olarak, demir çelik üretim sektörü son yıllarda çok gelişmiştir. Kullanılan hammadde ve üretim tekniklerine göre farklı türde üretim yapılabilmektedir. Türkiye ise bu sektörde Dünya'da 8. sırada bulunmaktadır. Türkiye'de üretimin büyük bir kısmı çelik hurda kullanılarak elektrik ark ocaklarında yapılmaktadır. Türkiye bu yöntemde kullanılan çelik hurdasını ithal ederek üretim yapmaktadır. Çelik hurda ithalatında Dünya'da ilk sıradadır.
Gelişen demir çelik endüstrisi, üretim esnasında oluşan atıkları depolayarak uzaklaştırmaya çalışmıştır. Fakat günden güne artan üretimle depolanan atıklar çevresel sorunlara yol açmıştır. Böylelikle bu atıkların faklı alanlarda geri kazanımı düşünülmeye başlanmıştır.
İnşaat sektöründe beton agregası olarak kullanılan doğal taşların elde edilmesi, giderek zorlaşmış ve maliyetli bir hal almıştır. Son yıllarda Dünya'nın farklı bölgelerinde demir çelik atığı olan cüruf beton agregası olarak kullanılmaya başlanmıştır. Böylece oluşan atıkların geri kazanımı küresel anlamda doğal kaynakları koruma ve çevreye verilen zararın azalmasına imkân sağlamıştır.
Bu çalışmada elektrik ark ocağı ile çelik üretimi sonucu atık olarak oluşan cürufun, karayolu esnek üst yapısı aşınma tabakasında agregaya alternatif olarak kullanılması sonucunda karışımın eğilme yüklerine karşı gösterdiği direnç ve kırılma davranışı araştırılmıştır.
Beş bölüm içeren bu tezin ilk bölümünde sanayi devrimi sonucunda kaynakların hızlıca tükenmesi sonucunda atık ürünlerin geri dönüşümünün gerekliliği anlatılmış, tezin amacı ve EAO cürufu ile ilgili geçmişte yapılan araştırmalara yer verilmiştir.
İkinci bölümde, karayolu üstyapısı tabakalarının özellikleri ve görevlerinden bahsedilmiştir. Bitümlü sıcak karışımlarda kullanılan agregaların karışımdaki görevleri ve özelliklerinin karışımı nasıl etkilediği anlatılmıştır. Ayrıca, karayolu üstyapısında kullanılan bitümlü sıcak karışımdan beklenen özellikler de detaylı olarak anlatılmıştır.
Çalışmanın üçüncü bölümünde, demir çelik üretim türleri ve oluşan cürufun karayolu üstyapısında agrega olarak kullanılması sonucunda beklenen özellikler açıklanmıştır. Ayrıca cürufun dünya genelinde kullanıldığı farklı alanlara da değinilmiştir.
Deneysel çalışmaların anlatıldığı dördüncü bölümde, EAO cürufu ve doğal kırmataş agrega üzerinde yapılan agrega deney ve sonuçları, şartname limitleri, optimum bitüm oranının belirlenmesi için yapılan Marshall tasarımı ve üç noktalı eğilme deneyi sonuçları yer almaktadır.
Son bölümde, yapılan çalışmaların genel sonuçlarına yer verilmiş ve EAO cürufunun aşınma tabakasında agrega olarak kullanımının karışımın eğilme dayanımı ve kırılma davranışı üzerindeki pozitif ve negatif yönleri değerlendirilmiştir. Ayrıca bundan sonra EAO cürufu ile ilgili yapılabilecek öneri çalışmalara yer verilmiştir.

Abstract:
Globally, the iron and steel production sector has developed greatly in recent years. Different types of production can be made according to the raw materials and production techniques used. When the worldwide production quantities of the first 10 countries in steel production for 2017 and analyzed changes in steel production compared to the previous year, Asian countries that account for more than half of the world steel market, China has realized 49.2% of world steel production in 2017 and Turkey With 13.1% increase, it is seen that it has the highest increase in production increase. In Turkey, it is ranked # 8 in the world. A large part of the production in Turkey is made in electric arc furnaces using steel scrap. Turkey is engaged in manufacturing by importing scrap steel used in this method. It ranks first in the world in steel scrap imports.
In the production of iron and steel, two different raw materials are used: iron ore and scrap. Production technique changes when raw material changes. Therefore, there are basically two different production techniques. The first of these is carried out by reaction of iron ore to iron oxide in blast furnaces and liquid iron is obtained. The other is the production of steel with electric arc cold from steel scrap.
The developing iron and steel industry tried to store and remove wastes generated during production. However, with the increasing production day by day, the wastes stored cause environmental problems. Thus, recycling of these wastes in different areas has started to be considered.
Obtaining natural stones used as concrete aggregates in the construction sector has become increasingly difficult and costly. In recent years, slag with iron and steel waste in different parts of the world has started to be used as concrete aggregate. Thus, the recovery of the generated wastes has enabled the protection of natural resources globally and the reduction of environmental damage.
In this study, the resistance and fracture behavior of the mixture against bending loads were investigated as a result of the use of slag formed as a result of electric arc furnace and steel production as an alternative to aggregate in road wear superstructure wear layer.
In the first part of this thesis, which contains five chapters, the necessity of recycling of waste products as a result of the rapid depletion of resources as a result of the industrial revolution is explained, the aim of the thesis and the past researches about EAF slag are mentioned.
In the second part, the characteristics and duties of the road superstructure layers are mentioned. The highway platform is divided into infrastructure and superstructure. The task of the superstructure is to provide driving safety and comfort by meeting traffic loads; to provide appropriate speed and braking distance to the wheels of the vehicle. rigid superstructure Only applicable on platforms with high traffic loads. This is because the rigidity of the superstructure requires high technical requirements and costs are high. Flexible superstructure is the most widely used coating type in our country and in the world. Flexible superstructure is made in two different qualities: superficial coating and bituminous hot mixture. The difference is that traffic loads are different. Superficial coating is low in strength and economical. Therefore, it is applied only on roads with low traffic. Bituminous hot mixture, on the contrary, is a high standard application. Generally, bituminous hot mixture is used because of its many advantages. The base floor forms the boundary of the flexible superstructure. It is prepared by leveling with splitting or storage material. It should be sufficient to prevent undesirable conditions such as swelling, shrinkage, undulation which may occur in the coating. The task of the sub-base between the floor and the base is to provide drainage of the platform. For this reason, granular material with low stability and high permeability is used. One of the functions of the foundation layer is drainage. In this way, it is expected to provide solutions to problems such as frost and swelling that may occur in the coating. Another function is the ability to resist shear stress by increasing stability. It is the part of the superstructure exposed to traffic load. 2 different layers are laid on the base layer. The duty of the coating layer is to resist shear stresses caused by traffic loads and to be elastic. In addition, leaking water is expected to be transferred to the base layer to be drained. The binder layer connects the wear layer with the base layer just below the wear layer. It has two main tasks. First; absorbing the temperature difference between the wear layer and the base layer. Secondly, and more importantly, it is able to transmit the shear stresses from the wear layer to the level that it can carry the base layer. It is the top layer of the coating layers. Since it takes the traffic load directly, its stability and durability should be higher than other layers. It also needs to absorb noise for driving comfort, be impermeable to prevent water from penetrating the substrates, and be resistant to wheel marking in terms of maintenance costs and safety. The tasks and properties of the aggregates used in hot bituminous mixtures are explained. In addition, the expected properties of bituminous hot mix used in road superstructure are explained in detail.
In the third part of the study, the types of iron and steel production and the expected properties of the resulting slag as aggregate in the road superstructure are explained. In addition, different fields where slag is used throughout the world are mentioned. Slag is used in the ballast layer on the railway. The use of slag has made the use of slag convenient and attractive, as slag complies with the standards of administrative institutions such as DDY, TSE, which are interested in railway construction works in our country. The Japanese specification for the use of slag in cement concrete has been put into effect since 2013. Another area of use of slag is coastal protection structures and cement concrete in ports. As an island country in Japan, coastal protection and harbor structures since 2009 rather than aggregate slag material has been used rather than positive results were obtained. It is also mentioned that it is very convenient to prevent erosion. Slag can be used as a cleaning agent (grit) in the shipbuilding industry. In this section, the use of slag as a road superstructure is also mentioned. Steel slag is used as superstructure layers, upper foundation and lower foundation. Many countries have specifications for use, and under these conditions, the use of slag in layers works successfully. The use of steel slag outside the road has become widespread. During the leveling process, it is used because of its contribution to strength in filling and ballast productions. If it is necessary to take a look at the historical process of slag applications and the spread of slag in the superstructure around the world, in Italy, slag applications instead of natural aggregates were found to be suitable as strength and environmental compatibility. The use of slag in Thailand since the 2000s has been successful. The following figure shows the slag applications. In 1992, the American National Slag Association stated that slag was used in the basic layers, fillers, coating layers and ballast making. In 2003, 19 M tons of steel slag was used in the US, contributing a market value of $ 150 M. It was reported that in 2010, 2.67 M tons of slag was used in Australia.
In the fourth chapter, the information about the materials obtained from various institutions are given in the experimental studies, the necessary experiments are applied to these materials and the results are compared with the KTŞ 2013. In the experimental studies, firstly experiments were carried out to determine the physical properties of the crushed stone aggregate obtained from Çiftalan Quarry and the bitumen obtained from Enfalt A.Ş. "Sieve analysis, Specific gravity and water absorption, Clay pellet and dispersible grain ratio, Flatness index, Los Angeles and Peel strength" and "Penetration, Ductility, Softening point and Specific gravity" tests were performed on the aggregates obtained. After the physical properties were determined, "density-gap "analyzes were performed by preparing 8 different mixtures with bitumen content ranging from 4.0% to 6.5% in 0.5% increments by Marshall design and" stability-yield "values were measured. The graphs of the obtained results were shown and the bitumen contents of the optimum values were determined according to optimum bitumen specification limits. Bitumen content, which keeps various parameters at optimum value, was calculated. After Marshal stability tests, asphalt beam samples of 7x7x28 dimensions were prepared with EAO slag ang natural crushed stone for three-point bending tests. Three-point bending tests were performed on the produced samples.
In the last section, the general results of the studies are given and the positive and negative aspects of the use of EAF slag as aggregate in the wear layer on the flexural strength and fracture behavior of the mixture are evaluated. In addition, the proposed studies related to EAF slag were included.