Date

2017

Author

Dağar, Volkan

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Tensile strength of clay, is a major mechanical parameter and is the main controlling parameter of tensile crack development which is generally encountered in geostructures. The researches to determine the tensile strength of clays are very limited. There are two kinds of methods which are used to measure the tensile strength of soils and these are named as, indirect and direct methods. In this experimental study, a direct tensile test apparatus was developed for measurement and understanding of the tensile characteristics of compacted clay soil. Also, split tensile test was used as an indirect method to measure the tensile strength of compacted clay soil. The clayey soil used in this study was collected from the Ankara, Turkey. Beside the tensile strength of Ankara Clay, the unconfined compression test on the same clay samples was also carried out. Tensile strength and unconfined compression test results were compared. Clays have low tensile strength compared with the compressive strength and to improve the tensile strength properties, the clay soil needs to be stabilized. Stabilization of a clay soil improves its strength and other engineering properties. In this study, the tensile strength of stabilized clays were also tested. Within the scope of this thesis, to monitor the stabilization and improvement of the tensile strength of clay soil, laboratory test were performed on Ankara clay and Kaolin clay with addition of three different kind of materials and various proportions of bentonite. The materials were synthetic fiber, pulverized rubber and metal swarf. It has been found from the experiments conducted that, the synthetic fiber were the only additive that improved the both split tensile strength and 8-shaped tensile strength. Adding pulverized rubber and metal swarf to the clayey soil did not cause any improvement nor on the tensile strengths neither on the unconfined compressive strengths. The data between the results of 8-shaped direct tensile tests, indirect split tensile tests and unconfined compression tests were correlated. The ratio of 8-shaped tensile strength to split tensile strength and to unconfined compressive strength was calculated to be 1.9 and 0.4, respectively. Also, the ratio of split tensile strength to unconfined compressive strength was calculated to be 0.2. Equations with coefficient of determination values of 0.90 and significance F values lower than 0.05, were developed according to the Ankara clay and Kaolin clay mixtures’ tensile strengths and index properties and were proposed to estimate the tensile strength of fine-grained soils from their index properties.

Subject Keywords

Clay., Kaolin., Clay, Strength of materials .

URI

http://etd.lib.metu.edu.tr/upload/12621211/index.pdf
https://hdl.handle.net/11511/26622

Collections

Graduate School of Natural and Applied Sciences, Thesis