Civil Engineering / İnşaat Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/13

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Author: search.filters.author.Saltan, MehmetLanguage: search.filters.language.en

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  • Article
    Investigation of the Effect of Aggregate Specific Gravity on Optimum Bitumen Content of Hot Mix Asphalt
    (2022) Saltan, Mehmet; Karadağ, Öznur; Uz, Volkan Emre; Kaçaroğlu, Gizem; Gökalp, İslam
    In this study, effect of aggregate specific gravity, which is directly related to origin of aggregates used in hot mix asphalt on optimum bitumen content, indirect tensile strength and tensile strength ratio of hot mix asphalt, was investigated. Specific gravity (SG) values of one kind of limestone aggregate were calculated according to Turkish Standard (TS), American Society for Testing and Materials (ASTM) and American Association of State Highway and Transportation Officials (AASHTO) standards, separately. Although one kind of limestone aggregate and 50/70 penetration grade bitumen are used in the mixtures, different values were obtained in terms of optimum bitumen content, indirect tensile strength and moisture sensitivity due to differences in the specific gravity values of the aggregates. Optimum bitumen contents were found by using TS, ASTM and AASHTO standards as 5.03%, 4.75% and 4.59%, respectively. According to the cost – benefit analysis, it can be said that changes in aggregate specific gravity values, which were calculated, based on different standards provide economic benefit. Overall, the results indicated that specific gravity values of one kind of limestone aggregate used in hot mix asphalt have significantly affected optimum bitumen content and indirect tensile strength of the mixtures.
  • Article
    Citation - WoS: 2
    Citation - Scopus: 3
    Site Assessment of Surface Texture and Skid Resistance by Varying the Grit Parameters of an Sma
    (American Society of Civil Engineers (ASCE), 2022) Gökalp, İslam; Uz, Volkan Emre; Saltan, Mehmet; Tepe, Mehtap
    For the sale operation of vehicles, pavement should provide adequate skid resistance, which can be achieved by using high polishing-resistant aggregate in wearing courses. However, supplying high-quality aggregate is not always feasible due to high transportation costs. For this reason, a method called gritting was adapted to meet the Highway Technical Specification (HTS) of Turkey in 2013. According to the method, for certain parts of the country, the wearing course can be constructed with local aggregates that have minimum polished stone value (PSV) of 40 (PSV >= 40), but, in this case, the surface must be covered with a high polishing-resistant aggregate (PSV >= 50), after the rollers' first pass. The objective of this study was to improve the present gritting method by investigating the effect of grit parameters on pavement performance under real traffic conditions. In this regard, during its construction, the wearing course of 0-51 Highway was gritted with different aggregate types (slags and natural), sizes (1-3; 1-5 mm), spreading amount (1.5; 2; 2.5 kg/m(2)), and spreading time (before and after the first pass of a roller) on eight test sections. Then, the macrotexture and skid resistance performance of these sections were evaluated under real traffic and environmental conditions for longer than 4 years. Changes in surface texture and skid resistance with respect to traffic were determined for each section. The results showed that higher skid resistance values were obtained at the sections gritted with metallurgical slags. Additionally, the sections gritted with 1-5 mm aggregates had better skid resistance than those gritted with 1-3 mm, while the change in mean texture depths were not very significant.
  • Conference Object
    Experimental Investigation of the Stabilization Performance of Geogrids for Unpaved Roads with Low Bearing Capacity Subgrade
    (Springer International Publishing AG, 2022) Gokova, Suleyman; Saltan, Mehmet; Terzi, Serdal; Tutumluer, Erol; Uz, Volkan Emre; Karasahin, Mustafa
    In this study, laboratory experiments were carried out on real sized samples to investigate the reinforcement performance of geogrids in highway pavements constructed on low bearing capacity subgrade (California Bearing Ratio, CBR = 3%). In all prepared samples, Hot Mix Asphalt (HMA) layer was not applied. A moving wheel load was applied with Accelerated Pavement Tester (APT) device on representative pavement samples 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 have been calculated from surface profiles measured with a laser profiler and were plotted versus number of load repetitions. As a result of this study, the use of geogrid over soft subgrade with lowCBR values has been shown to extend the life of the pavement by reducing the rut depth.