Civil Engineering / İnşaat Mühendisliği

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

Browse

Filters

2011 - 201912020 - 20233

Settings

Subject: search.filters.subject.Sustainability

Search Results

Now showing 1 - 4 of 4
  • Review
    Citation - WoS: 42
    Citation - Scopus: 49
    Utilization of Waste Materials in the Stabilization of Expansive Pavement Subgrade: an Extensive Review
    (Elsevier, 2023) Tanyıldızı, Muhammed; Uz, Volkan Emre; Gökalp, İslam
    Expansive soils, also known as swell-shrink soils, are one of the most problematic soils in highway construction and exhibit significant volume changes by swelling and shrinking while wet and dry, respectively. These changes in soil cause cracks, heaves, differential settlements, and damages to the overlying pavements leading to high maintenance costs. The annual average maintenance cost of structures built on expansive soils ranges from $9 to $15 billion, with 50% of the expenses associated with highways and streets. Chemical stabilization techniques such as cement and lime stabilization are one of the most efficient ways to treat expansive soils. However, there is a need to develop environmentally friendly approaches to stabilize expansive soils due to worldwide growing interest in sustainable developments and concerns about greenhouse gas emissions and climate change. In this context, using waste materials in soil stabilization has been considered an important issue for sustainability concerns. The aim of the current study is to review the relevant studies performed to improve the geotechnical and engineering properties of expansive subgrade soils of pavements by using waste materials arising from industrial, agricultural, and other activities in the last decade. In the organization of this study, characteristics of expansive soils including plasticity, compaction, strength & stiffness, microstructural characteristics, shrink-swell properties, and durability were focused to point out the effect of the waste materials. The overall results obtained throughout the scope of the current study indicated that the use of waste materials in soil stabilization improves the engineering properties of expansive soils, significantly. This paper also provides key information and creates awareness for researchers and sector representatives about sustainable soil stabilization.
  • 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.
  • Article
    Citation - WoS: 5
    Citation - Scopus: 6
    Sustainable Production of Aging-Resistant Bitumen: Waste Engine Oil Modification
    (American Society of Civil Engineers, 2021) Gökalp, İslam; Uz, Volkan Emre
    Using waste engine oil (WEOIL) within bituminous binders might be one of the most energy-efficient and sustainable means of producing aging-resistant bitumen due to the antioxidative properties of WEOIL. In this paper, the use of WEOIL to obtain aging-resistant bitumen and its optimum rates for short and long terms were investigated. In this regard, a base bitumen was modified with WEOIL in certain rates ranging from 1% to 5% by weight of bitumen. Then base and oil-modified bitumen samples were subjected to aging. To define the changes in rheological properties of bitumen based on rutting, fatigue, and thermal cracking resistance, dynamic shear and bending beam rheometer tests were performed on each sample. Furthermore, an aging index (AI) analysis was performed for both the short- and long-term aging conditions to express the effect of WEOIL on aging resistance of the bitumen. According to the AI analysis, short-term-aging-resistant bitumen is obtained by adding 3.5% WEOIL to the base bitumen, while a 5.8% contribution rate is required to avoid the long-term aging effect. Moreover, the increase in rate of WEOIL content improved the low-temperature cracking resistance. Consequently, utilizing WEOIL for production of aging-resistant bitumen can provide environmental and economic benefits based on conservation of natural resources and waste recycling.
  • Conference Object
    Sustainability of Groundwater and Its Effects on Ecosystems
    (National Academy of Sciences of the Kyrgyz Republic (NAS KR), 2011) Baba, Alper; Gündüz, Orhan
    Groundwater’s global role as a vital source of fresh drinking water is well documented, and efforts are underway in many parts of the world to manage groundwater reserves responsibly and sustainably. A large percentage of the world’s population lives in cities and either depends on or is affected in some way by groundwater. This ever increasing demand on groundwater has led to overexploitation of the aquifers and degradation of groundwater quality particularly in the last 50 years. Available evidences indicate that regional changes in climate (i.e., increases in temperature and reduction in precipitation totals and patterns) have already affected groundwater resources and ecosystem in many parts of the world. In future, climate change is expected to intensify groundwater related problems due to reduced recharge rates and increased demand for domestic, agricultural and industrial water supply. Thus, the basic concern is the sustainable management of groundwater resources such that it is not depleted while the increasing demand is effectively satisfied. Based on these fundamentals, the purpose of this study is to present an overview of groundwater problem in different parts of the world and to present an overview of the current knowledge in the area of climate change impacts on water resources. Case studies from the Mediterranean Region, the Caspian Sea Region and the Aral Sea where safe water resources are typically scarce and became steadily scarcer are presented. In particular, access to high quality drinking water will become more of a problem than it currently is in these and in many other parts of the world. Decreasing precipitation and reduced recharge of groundwater resources are now considered to be one of the reasons for declining groundwater quality. Finally, these drastic changes in the hydrology of the groundwater system are also responsible for many changes in ecosystems where some are irreversible.