Browsing by Author "Sari, Yasin Dursun"

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Citation - WoS: 10
Citation - Scopus: 9
Bacteria-Induced Cementation in Sandy Soils
(Taylor & Francis inc, 2015) Gurbuz, Ayhan; Sari, Yasin Dursun; Yuksekdag, Zehra Nur; Department of Civil Engineering
Bacteria-induced calcite precipitation (BICP) is a promising technique that utilizes bacteria to form calcite precipitates throughout the soil matrix, leading to an increase in soil strength and stiffness. This research investigated BICP in two types of sands under sterile and nonsterile conditions. Bacteria formation and BICP in the sterilized sand specimens are higher than those in the nonsterilized sand specimens. The development of calcite with time is initially greater for the sand specimens containing calcite. Scanning electron microscope imaging allowed the detection of cementation from calcite precipitation on the surface and pores of the sand matrix. The effects of injecting nutrient mediums and bacteria into the specimens, as well as pH of soil samples on BICP were investigated. The bearing capacity of biologically treated vs. untreated sand specimens were determined especially by laboratory foundation loading tests.
Citation - WoS: 13
Citation - Scopus: 16
Cementation in a Matrix of Loose Sandy Soil Using Biological Treatment Method
(Academic Journals, 2011) Gurbuz, Ayhan; Sari, Yasin Dursun; Yuksekdag, Zehra Nur; Cinar, Berat; Department of Civil Engineering; Department of Civil Engineering
Man-made materials varying from cement-based to chemical-based have been injected into soils to improve their engineering properties (shear strength, compressibility, permeability, bearing capacity etc.). Soil type in general plays important role in determination of treatment material and method. Materials used for soil treatment might have side effects in terms of air pollution, soil or water contamination etc. during manufacturing or application. An alternative, environmentally friendly soil treatment method that is based on the use of bacteria present in soils and named Biological Treatment Method (BTM) has been used by researchers to bond particles of loose sandy soils via creation of calcite (CaCO3) generated by bacteria using urea to influence the precipitation of calcium carbonate. This study presents the results of bacterial induced cementation (BIC) in matrix of loose sandy soil. A bacterium used in this study is Sporosarcina pasteurii that is naturally present in soils and is aerobic type. The bacteria grown in laboratory environment were injected to the matrix of loose sandy soil. Subsequent nutrient mediums were introduced to specimens to accelerate the development of cementation level. Number of bacteria, pH level, temperature and amount of CaCO3 were measured during the duration of testing. Images of Scanning Electron Microscope (SEM) showed that creation of cementation from precipitation of CaCO3 on the surface and pores of soil matrix were observed for only sand samples into which nutrient was flushed on sequence of arbitrary time.
Citation - WoS: 11
Citation - Scopus: 21
Numerical Analysis of a Tunnel Support Design in Conjunction With Empirical Methods
(Asce-amer Soc Civil Engineers, 2008) Sari, Yasin Dursun; Pasamehmetoglu, A. Gunhan; Cetiner, Erkan; Donmez, Senayi; Department of Civil Engineering
In this paper, preliminary support design of a tunnel was analyzed by numerical and empirical approaches. The case study for this analysis is a tunnel to be constructed on the Bilecik-Istanbul roadway in Turkey. The rock mass properties of the tunnel route and design support recommendations were obtained by using an empirical approach. The rock mass properties obtained from the empirical method were used as input parameters for the numerical analysis. The empirical and numerical results, in terms of support design, were evaluated. It was seen that the numerical analysis results supported by empirical values were logical and reliable.
Citation - WoS: 128
Citation - Scopus: 165
Re-Usage of Waste Foundry Sand in High-Strength Concrete
(Pergamon-elsevier Science Ltd, 2010) Guney, Yucel; Sari, Yasin Dursun; Yalcin, Muhsin; Tuncan, Ahmet; Donmez, Senayi; Department of Civil Engineering
In this study, the potential re-use of waste foundry sand in high-strength concrete production was investigated. The natural fine sand is replaced with waste foundry sand (0%, 5%, 10%, and 15%). The findings from a series of test program has shown reduction in compressive and tensile strengths, and the elasticity modulus which is directly related to waste foundry inclusion in concrete. Nevertheless the concrete with 10% waste foundry sand exhibits almost similar results to that of the control one. The slump and the workability of the fresh concrete decreases with the increase of the waste foundry sand ratio. Although the freezing and thawing significantly reduces the mechanical and physical properties of the concrete. The obtained results satisfies the acceptable limits set by the American Concrete Institute (Ad). (C) 2010 Elsevier Ltd. All rights reserved.