Yazar "Saltan, Mehmet" seçeneğine göre listele

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    Bitumen expanding using bio-oil product of rose pulp's pyrolysis process
    (Elsevier Sci Ltd, 2020) Terzi, Serdal; Saltan, Mehmet; Armagan, Kemal; Kurtman, Akay Kurter; Karahancer, Sebnem; Eriskin, Ekinhan; Uz, Volkan Emre
    Within the study, the usability of rose pulp, which is the common waste of many industrial products produced by using rose, was examined as bitumen modification material. In order to investigate this possibility and potential benefits, waste rose pulp was subjected to the pyrolysis process to obtain the biochar, bio-oil and biogas. Since it has a viscous liquid form, the bio-oil product has been selected to modify the bitumen for this study. Supplied wet rose pulp was first dried until the water content decreases to around 10%. Afterwards, the dried rose pulp subjected to pyrolysis process for one hour at 450 degrees C after 30 min heating period. Used neat bitumen's grade was PG 64-22. Bio-oil product has been mixed 2 and 4% by weight into the bitumen at 160 degrees C for 30 min. After the modification process, bitumen performance tests have been done. Because of the analysis, it was concluded that modification did not change the bitumen grade, reduced the mixing and compaction temperature up to 8 degrees C and so saving energy. In addition, the modification increases the optimum bitumen ratio up to 5%, strength value up to 4.1%, tensile strength ratio (TSR) value up to 2.3%, and the wheel tracking depth up to 95.2% but still remains within the Hamburg wheel tracking test specification limits. (C) 2020 Elsevier Ltd. All rights reserved.
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    Experimental investigation of the stabilization performance trends of two geogrids constructed on low bearing capacity subgrade
    (Korean Geosynthetics Society, 2018) Gökova, Süleyman; Saltan, Mehmet; Terzi, Serdal; Tutumluer, Erol; Uz, Volkan Emre; Karaşahin, Mustafa
    Experiments were carried out on real size samples in the laboratory to investigate the geogrid stabilization performance in highway pavement applications. A moving wheel load was applied on representative pavement samples constructed on low bearing capacity subgrade with and without geogrids. Two types of geogrids were used to construct the pavement sample configurations. Resistance to plastic (permanent) deformation was recorded as a performance indicator to compare structural performance trends of the pavement samples. For this objective, surface deformations were measured after certain wheel load repetitions. Rut depths were calculated from surface profiles measured with a laser profiler. Layer thicknesses were varied to observe differences in the deformation trends. When appropriate conditions were reached in the trial configurations, all layer thicknesses were kept constant during the tests. The two geogrid types constructed with the same granular materials and varying layer thicknesses were used in different layer interfaces to search for the most optimum solution. According to the study findings, the use of geogrid over soft subgrade with low CBR values has been shown to extend the life of the pavement by reducing the rut depth. Copyright © 11th Inter. Conf. on Geos. 2018, ICG 2018. All rights reserved.
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    Feasibility of Using 4th Power Law in Design of Plastic Deformation Resistant Low Volume Roads
    (Elsevier Science Bv, 2016) Uz, Volkan Emre; Saltan, Mehmet; Gokalp, Islam
    A low volume road (LVR) structural design has two phases: first one is selection of appropriate construction materials and second is the determination of layer thicknesses under the certain traffic and environmental conditions with considering the subgrade bearing capacity. Pavements are prompted to serve the traffic without reaching the terminal serviceability index over its design life. Rut accumulation (plastic deformation) is the most common pavement deterioration type of flexible pavements. Therefore the main goal of the design is prevent rutting. Many low volume road design manual assume that plastic deformation occurs only in subgrade. Construction of overlying layers by selective high performance materials according to the related material and construction specifications is the reason of this assumption. In fact, the assumption is not much reasonable especially for with no, or thinly overlaid low volume road pavements, where the major structural strength is comprised of unbound granular pavement materials and where the principal distress mechanism is rutting in the aggregate layers. Subgrade bearing capacity and the traffic are the main input parameters in the design stage of low volume roads. Subgrade bearing capacity is expressed with California Bearing Ratio (CBR) or Resilient Modulus (Mr). The traffic term is determined by Equivalent Standard Axle Load (ESAL) repetitions which is often admitted as 80 kN single axle load. Although it is not too difficult to determine an axle load for an individual vehicle, it becomes quite complicated to determine the number and types of axle loads that a particular pavement will be subjected over its design life. For calculation of Load Damage Factors of different vehicle types, which have various axle load and configurations, a generalized fourth-power law has been used for more than a half century. The objective of this study is to indicate the limitations and difficulties faced on reliably applying a power law relationship in design of LVRs with no, or only thin seals. If a power law relationship to be used due to its simplicity, several parameters must be considered in selection of the power value. Such as stress dependent behavior of unbound granular materials and the selected distress type.
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    Investigation of chip seal performance under cold climate conditions
    (Walter De Gruyter Gmbh, 2016) Karasahin, Mustafa; Guerer, Cahit; Saltan, Mehmet; Taciroglu, Murat V.; Uz, Volkan Emre
    The chip seal is an economical type of asphalt pavement that was constructed for single-or double-layer aggregate-bitumen. Chip seals are applied to prime-sealed granular pavement surfaces in order to waterproof the surfaces of sub-layers, produce smooth and high-skid-resistance surfaces for vehicles and protect pavements against the detrimental effects of traffic and climate. Unlike bituminous hot mixtures, numerous factors can affect the performance of chip seal. One of the most important factors is climate. The aim of this study is to determine the performance variation of chip-sealed pavements under cold climate conditions. Three different chip-sealed roads in Erzurum, which is in one of the coldest regions of Turkey, were examined with non-destructive tests. Sandpatch, British pendulum, light weight deflectometer and dynamic cone penetrometer tests were performed. Chipsealed pavements' densities and surface temperature variation and base courses layer's thicknesses were also measured, and deteriorations were observed and scored by researchers. Test results showed that flushing due to the higher temperatures during the short summer season, deficiency of the base course's bearing capacity and moisture in the base course are the most important causes of deterioration in this type of chip seal, and the chip seals in this region must be resealed in <1 year because of the premature deterioration.
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    Technical and environmental evaluation of metallurgical slags as aggregate for sustainable pavement layer applications
    (Elsevier, 2018) Gokalp, Islam; Uz, Volkan Emre; Saltan, Mehmet; Tutumluer, Erol
    The paper examines physical, mechanical and chemical properties of slags, by-products of the metal industry, and evaluates their suitability for use as aggregates in pavement layers for the sustainability to be achieved in road construction. Samples of both metallurgical slags (steel and ferrochromium slags) and natural aggregates (limestone, basalt, and boulder) were obtained to determine their physical, mechanical, chemical properties through laboratory testing. Leaching tests and Inductive Coupled Argon Plasma Mass Spectrometry analyses were also conducted on the slags to determine whether they posed any detrimental effects on the environment. In addition, scanning electron microscope was utilized to determine the surface roughness of aggregates. The slag properties determined were compared to certain limits provided in the Highway Technical Specifications (HTS) and Waste Disposal Regulations (WDR) of Turkey. In conclusion, physical and mechanical properties of slags satisfied the HTS requirements and leaching test results showed that the slags studied were inert materials based on WDR. Therefore, not only economic and environmental but also technical benefits can be provided by utilizing slags in pavement construction as a sustainable alternative. (C) 2017 Elsevier Ltd. All rights reserved.
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    Testing the abrasion resistance of aggregates including by-products by using Micro Deval apparatus with different standard test methods
    (Elsevier Sci Ltd, 2016) Gokalp, Islam; Uz, Volkan Emre; Saltan, Mehmet
    Structural and functional performance of a pavement is affected by aggregate properties; therefore, characterizing the aggregate properties is crucial. Series of tests are conducted on road construction aggregates, not only for selection of appropriate aggregate which meets related specifications, but also for estimation of the long-term performance of aggregates particularly for economic and safety reasons. Micro-Deval (MD) test is the most common test used for qualifying aggregates on behalf of resistance to wear. This paper compares the European (EN) and US (ASTM) standard methods for the MD test. For comparison, MD tests were conducted on six different natural aggregates and four different by-products according to different standards. Three types of limestone, two types of basalt and one boulder were used as natural aggregates, and three types of Electric Arc Furnace steel slag and one Ferrochrome slag were selected as by-products. Physical, mechanical, and chemical properties of the aggregates were also determined. The test results show that both methods produce different mass losses with different aggregate type and grain size. The percentage loss in mass which is referred to as Micro Deval Coefficient MDC with EN 1097-1 method is higher than all gradations of ASTM method except for Ferrochrome slag. Moreover, the results obtained with ASTM test method show that MDC values are increasing with increase of grain size in natural aggregates but, this tendency is not observed in slags. (C) 2016 Elsevier Ltd. All rights reserved.
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    Use of glass waste as mineral filler in hot mix asphalt
    (Walter de Gruyter GmbH, 2015) Saltan, Mehmet; Öksüz, Betül; Uz, Volkan Emre
    The use of resources is increasing due to continuous increase in world population and rapid industrialization, while natural resources are being exhausted day by day. Usage of waste materials or by-products in highway construction has substantial environmental and economic benefits. In this study, the usage of cullet and waste glass bottle dust as mineral filler material in hot mix asphalt as an alternate to traditional crushed stone dust was investigated. Optimum bitumen content was determined by the Marshall mix design method by using six different bitumen contents (4.0%, 4.5%, 5.0%, 5.5%, 6.0%, and 6.5%). With the optimum bitumen content, three different mineral filler types (cullet, glass bottle waste, and stone dust) and six different filler ratios (4%, 5%, 6%, 7%, 8%, and 9%) were used to prepare asphalt mixture samples. Samples were performed using the Marshall stability test, and the results were compared. It is concluded that cullet and glass bottle waste can be used in asphalt mixtures as a mineral filler alternate to crushed stone dust if the economic and environmental factors favor it. © by De Gruyter 2015.
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    Yüzeysel Kaplamalarda Agrega Tür, Boyut ve Cilalanma Seviyesinin Kaplama Kayma Direncine Olan Etkisinin Laboratuvar Ortamında Araştırılması
    (2016) Uz, Volkan Emre; Saltan, Mehmet
    Bu çalışmasının amacı, laboratuvar ortamında farklı agrega tür, tane boyut ve cilalanma seviyelerinde üretilen yüzeysel kaplamaların kayma direnci performansının araştırılmasıdır. Sathi ve harç tipi kaplamalarının üretiminde kireç taşı, bazalt ve dere malzemesi kökenlerinde altı farklı doğal agrega ve elektrik ark fırını ile ferrokrom cüruflarını içeren dört farklı atık kullanılmıştır. Her bir agreganın fiziksel, mekanik ve kimyasal özelikleri EN standartlarına göre belirlenmiş ve elde edilen sonuçlar, Türkiye Karayolları Teknik Şartnamesindeki (KTŞ) şartname limitleri ile kıyaslanmıştır. Sathi kaplama örnekleri, 2,00-19,00 mm aralığında değişen yedi farklı tane boyutunda hazırlanırken, harç tipi kaplama örnekleri üç farklı gradasyonda üretilmiştir. Yüzey dokusunun kaplama kayma direncine etkisi bilindiğinden, yüzeysel kaplama örneklerinin ortalama doku derinlikleri, kum yama ve akış ölçer testleri ile sırasıyla ASTM E 965 ve ASTM E 2380 standart metotlarına göre belirlenmiştir. Agregaların cilalandırılması, aşınmaya karşı direncin incelenmesinde kullanılan Micro-Deval cihazı aracılığı ile ASTM D 6928 standardına göre yapılmıştır. Farklı seviyelerde cilalanmış agrega temin etmek için 5.250?den 52.500 değişen beş farklı devirlerde Micro-Deval testi uygulanmıştır. Testlerden sonra, cilalanan agregalar elenmiş, sathi kaplama örneklerinin hazırlanması için 4-12,5 mm aralığında değişen dört farklı tane boyutunda ayrıştırılmıştır. Agrega yüzeylerinin belirli cilalanma seviyelerinde görüntülenmesi için, taramalı elektron mikroskobu kullanılmıştır. Son olarak, laboratuvarda üretilen her bir yüzeysel kaplama numunesinin kayma direncini belirlemek için İngiliz Sarkacı Testi (British Pendulum Test), ASTM E 303 standart metoduna uygun olacak şekilde kullanılmıştır. Tüm analizler dikkate alınarak, makro ve mikro cinsinden yüzey dokusunun cilalanmamış ve cilalanmış durumdaki agregalar ile üretilmiş yüzeysel kaplamaların kayma direncine olan etkisi incelenmiştir. Kayma direnci ile ilişkilendirilen yüzey dokularının analizleri neticesinde, mikro dokunun kayma direnci performansında önemli ölçüde belirleyici olduğu görülmüştür. Yüzeysel kaplamaların kayma direnci karşılaştırıldığında, her cilalanma seviyesinde cüruflar ile üretilmiş olan numunelerin, doğal agrega ile üretilmiş olan numunelerden daha iyi performans gösterdiği gözlenmiştir. Cürufların geri kazanımı ile sadece çevresel ve ekonomik açıdan yarar sağlanmış olmayacak, aynı zamanda cürufların yüzeysel kaplamalarda kullanımı ile kayma direnci yüksek uzun ömürlü kaplama yüzeylerin elde edilmesi sağlanacaktır. Bu çalışma ile cüruf kullanarak yüksek kayma direncine sahip kaplamaların inşa edilebileceği ve böylelikle kayma tipi kazaların ve can ve mal kayıplarının azaltılabileceği sonucuna varılabilir.