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Options of determining the frost resistance of concrete in a structure
Jindrová, Barbora ; Vymazal, Tomáš (referee) ; Kocáb, Dalibor (advisor)
The diploma thesis deals with different methods of determining levels of degradation of concrete due to freezing, also considering the options of freeze thaw resistance determination in structure. At first the properties of concrete and possible mechanisms of concrete degradation are described – mainly the effects of freezing water in the inner structure and of the combination of freezing water and de-icing chemicals on the surface. Principle and properties of air-entrained concrete are also mentioned. An overview of the approaches that current standards use to determine the freeze-thaw resistance of concrete is listed, followed by description of the tests that are used on air-entrained concrete specimens in the main part of the thesis. A portion of the test specimens was made in moulds while the rest was obtained from structure (concrete block). The non-destructive tests used are evaluated in several different ways and their results are compared with the destructive tests. Comparison and evaluation of different approaches used to determine the freeze-thaw resistence of concrete are the main outcome of this thesis.
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Ověření pevnostních charakteristik vybraných lamel roštů lůžkového nábytku
Chladil, Vít
The bachelor thesis deals with the testing of bed lamellas and laths. More specifically, it evaluates whether the load pattern will withstand or be damaged. In case of damage, it determines the weight at which this condition occurs. It further evaluates the level of deflection. The first part deals with the history of bed grates and their types, ways of fixing slats and slats. This section also briefly describes how to correctly select a bed grate to suit a particular customer. The second part deals not only with the evaluation of the results of the individual tests but also with the verification of the level of deflection of the strength characteristics of the selected lamellas and laths. At the end of the thesis, recommendations are proposed based on testing to improve the strength characteristics of the lamellas and laths, so as to avoid breaking the samples.
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Degradační procesy elastomerů
Hrabčík, Jiří
The diploma thesis is focused on analysis of degradation process of elastomeric materials which come to contact with certain selected environments. The thesis describes all types of polymer materials along with their properties that specify their area of application, not only in technical practice. The experimental part of the thesis analyzes the intensity and effects of degradation processes of elastomeric materials which come to contact with selected hydrocarbon fuels. The analysis is based on measurements of dimensions, weight and strength characteristics of individual samples with subsequent evaluation of the consequences of the application in particular kinds of environments.
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Options of determining the frost resistance of concrete in a structure
Jindrová, Barbora ; Vymazal, Tomáš (referee) ; Kocáb, Dalibor (advisor)
The diploma thesis deals with different methods of determining levels of degradation of concrete due to freezing, also considering the options of freeze thaw resistance determination in structure. At first the properties of concrete and possible mechanisms of concrete degradation are described – mainly the effects of freezing water in the inner structure and of the combination of freezing water and de-icing chemicals on the surface. Principle and properties of air-entrained concrete are also mentioned. An overview of the approaches that current standards use to determine the freeze-thaw resistance of concrete is listed, followed by description of the tests that are used on air-entrained concrete specimens in the main part of the thesis. A portion of the test specimens was made in moulds while the rest was obtained from structure (concrete block). The non-destructive tests used are evaluated in several different ways and their results are compared with the destructive tests. Comparison and evaluation of different approaches used to determine the freeze-thaw resistence of concrete are the main outcome of this thesis.
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