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Possibilities of evaluation durability of the surface layer of concrete structures
Blažek, Michal ; Žalud, Oldřich (referee) ; Vymazal, Tomáš (advisor)
The thesis is focused on possibilities of durability evaluation of surface layer of concrete structures. The durability of concrete surface layer usually determines the durability of the structure as a unit. It has to be determined in what environment the structure is situated and what influences it has to face, to set the durability of the structure. There is a several normative prescription to set the resistance of the structure. There is formulated a summary of the most widely used and known prescriptions in the theoretical part of the thesis. It is a lot of effort to estimate the durability of the concrete by estimation of permeability of the concrete surface layer recently. Thus these methods are also formulated in the summary and there are compared the individual outputs of the tests. The permeability and pore structures of the concrete surface layer are crucial parameters for the durability of concrete structure. These parameters influence the construction properties of the concrete as well, thus the thesis is focused on relationship of the pore structure and the strength in press of the concrete.
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Possibities to increase the frost resistance of brick body
Keršner, Štěpán ; Šveda,, Mikuláš (referee) ; Sokolář, Radomír (advisor)
This thesis, which comprises of a theoretical and a practical part, deals with possible means of increasing ceramic body frost resistance. The current state of research in the field of ceramic body frost resistance is summarized in the theoretical part. The practical part is divided into two sections. In the first section, the influence of firing temperature (820 °C and 1020 °C) and duration (2, 4 and 6 hours) on frost resistance and several other parameters is assessed by means of experiment, using a specimen of brick body made of mixes currently used in roof tile production by TONDACH Šlapanice and TONDACH Dolní Jirčany factories. In the second section of the practical part, two modifications are introduced of the mixture currently used in roof tile production in the TONDACH Šlapanice factory – GE clay and zeolite supplements were added, the effects of which are verified by means of experiment using specimens fired in a kiln designated for ceramic masonry blocks and alternatively in a kiln used for firing TONDACH Šlapanice roof tiles.
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Methodology of historical bricks and masonry tests
Bartoň, Vojtěch ; Anton, Ondřej (referee) ; Cikrle, Petr (advisor)
This diploma thesis is focused on methodology for sorting of solid fired bricks for reconstruction of historical buildings. The theorethical part of this thesis includes description of production technology of solid fired bricks and diagnostic methods. In practical part there are these methods aplied on the solid fired bricks, which are intended for reconstruction of the bridge in Sedlec. There are monitored changes in structure of solid fired bricks caused by repeated freezing and defrosting. This changes are monitored by resonant frequency method and ultasonic pulse method.
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Utilization of clays with low sintering temperature in brick technology
Sláma, Jakub ; Skotal, Zbyněk (referee) ; Sokolář, Radomír (advisor)
Bachelor thesis focuses on the use of the low sintering clays as additives in brickmaking. Their main use in the brick industry is mainly in the production of facing bricks and roof tiles. They are used for their very good sintering ability even at relatively lower firing temperatures. This feature is the most important for frost resistence of brick fragment. The theoretical part contains a summary and characteristic features of clays occurring in the Czech Republic and abroad. Further their requirements and laboratory testing of brick clay. In the practical part was conducted market research where are outlined available low sintering clays that may be proposed for use in brick fragment based on declared sintering. An experiment was performed in the next part of bachelor thesis to assess the effect of using low sintering clay in terms of particular brick factory in the Czech Republic (Tondach Šlapanice).
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The comparison of testing methods using for determining the frost resistance of concrete
Kněbort, David ; Vymazal, Tomáš (referee) ; Kocáb, Dalibor (advisor)
The diploma thesis deals with the possibilities of evaluating the degradation of mechanical resistance of non-air-entrained concrete in the structure by frost cycles. The first part is focused on concrete, its resistance and test methods. This is followed by the definition of frost resistance, the effects of freeze-thaw on concrete at all stages of its service life and the possibilities of determining freeze-thaw resistance according to current standards. It describes in more detail selected test methods for determining frost resistance. In the practical part, it focuses on the determination of degradation resistance of test specimens made in molds and taken from the structure using reference and non-reference methods. In conclusion, it compares the different test methods and their suitability for the determination of freeze-thaw resistance.
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Studying the possibility of improving the frost resistance of concrete
Šafrata, Pavel ; Ťažký, Tomáš (referee) ; Hela, Rudolf (advisor)
The purpose of this study is to summarize theoretical and practical knowledge of frost resistance of concrete. It suggests, that there are numerous factors affecting the freeze-thaw resistence of concrete. These are especially raw materials, production technology, time and method of curing. The influence of addition, air entrainment and air void structure is complied and evaluated experimentally. The testing method is crucial for the evaluation of durability of concrete. Hence, this thesis includes a research of methods used around the world and practical comparison of some of them. This thesis is valuable because of implementation of the requirement in the standard ČSN EN 206 (2014) for the frost resistence of concrete in exposure classes XF1 and XF3.
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Frost resistance of clay roofing tiles - methodology of laboratory testing
Khongová, Ingrid ; Stančík,, Hynek (referee) ; Sokolář, Radomír (advisor)
This bachelor´s work is focusing on a frost resistance of clay roofing tiles. Frost resistance is among the most important parameters, which is derive from its resistance and lifespan. Direct laboratory methods are very time-consuming so there is a great effort to improve indirect methods, which could most likely determine if tested clay roofing tile is frost resistance or not. Main targer of this bachelor´s work is to summary present knowledge about a issue of frost resistance, description of making frost resistance brick body and description of used methods establishing frost resistance. Practical part is focused on a different tests, which give us informations about microstructure and characteristic of a ceramic body.
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The frost susceptibility of the soils and materials to subgrade of the pavements
Mašek, Jakub ; Zajíček, Jan (referee) ; Stehlík, Dušan (advisor)
This diploma thesis deals with the issue of the determination of the frost susceptibility of soils in the subgrades of road structures. The theoretical part compares the ways of testing the frost susceptibility in the Czech Republic and other selected countries of the European Union. Furthermore, it also deals with the development of the frost susceptibility index in the Czech Republic. The empirical part focuses on the laboratory testing of the frost susceptibility of the given sample of soil by the direct frost heave method. Moreover, it also deals with the simulation of penetration of frost by the subgrade and the possibility of shortening the length of the freezing during the direct testing the frost susceptibility.
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The effect of reduction core on the water impermeability and frost resistance of brick body
Kučera, Tomáš ; Stančík,, Hynek (referee) ; Sokolář, Radomír (advisor)
The bachelor thesis reviews effect of reduction core on the basic physical and mechanical properties of fired roof tiles. Theoretical part summarizes the knowledge about the reduction cores effect on the properties of the brick body and describes the basic rules for the successful reduction core elimination during firing of the brick body. In the experimental part are mainly compared properties of porosity, bend strength, impermeability and frost resistance of laboratory prepared samples and those are compared based on differently developed reduction core due to different firing.
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