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The development of high-strength concrete with a high content of el. fly ash
Roubal, David ; Ťažký, Tomáš (referee) ; Hela, Rudolf (advisor)
This diploma thesis deals with the study of high-strength, high-volume fly ash concrete. The theoretical part of this thesis focuses on the detailed characteristic and main principles of high-strength concrete, high-volume fly ash concrete. In addition, according to the findings, the technology of high-strength and high-volume fly ash concrete, including principles of high strength, has been described. On the basis of the findings, high-strength, high-volume fly ash concrete for specific compressive strengths has been designed and created in the experimental section. These concretes were then subjected to a number of tests.
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Possibilities of using of fluid fly ash in the self-leveling systems
Zárybnická, Klára ; Bílek, Vlastimil (referee) ; Opravil, Tomáš (advisor)
The work deals with the study of possibilities of using fluid ashes in self-leveling floor systems. The task of this work is to reach a proper composition of self-leveling floor mixture with high capacity of fluid ash in binding compoment, which means replacement of portland cement primary. In the work there are monitored mechanical and durable properties of tested self-leveling systems, which are evaluated according to valid norm. Especially the work is focused on volume changes during hydratation and maturation of new designed self-leveling systems, because thanks to high capacity of free lime and anhydrite in fluid ashes there are volume changes thanks to formation of ettringite.
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Preparation of modified tricalcium aluminate phases and study of their hydratation processes
Vávrová, Alžběta ; Koplík, Jan (referee) ; Másilko, Jiří (advisor)
This diploma thesis deals with the preparation of modified tricalcium aluminate phases using sodium ions, and the study of their hydration processes and products. The X-ray diffraction analysis, isothermal calorimetry, laser diffraction, and scanning electron microscopy with energy dispersion analysis were used to solve this task. The preparation of modified tricalcium aluminate phases using high temperature methods has been described in the experimental section. Furthermore, the X-ray diffraction analysis was used to determine the purity of the prepared phases and the scanning electron microscopy with energy dispersion analysis was used to define the volume of sodium. Laser diffraction was used to measure a particle size distribution in the individual phases. Subsequently, hydration of the pure phases was performed in an isothermal calorimeter. It was followed by hydration of phases in the presence of different gypsum content and then in the presence of saturated portlandite solution. Hydration of some samples was stopped in order to better understand the hydration process. Hydration products were studied by X-ray diffraction analysis. The obtained results were compared with each other and the influence of sodium ions on both the structure of the prepared phases and the course of hydration and its products has been discussed. The effect of adding different volumes of gypsum and portlandite on the course of hydration of the individual phases was also compared.
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Cement worm conveyor
Weingärtner, Jan ; Malášek, Jiří (referee) ; Škopán, Miroslav (advisor)
This bechelor‘s thesis deal with constructional analysis of the worm conveyor. I describe here design calculation of main parts of conveyer, design of propulsive system, solidity control of functional parts, problem of heat dilatation while higher temperatures transported materials and way of mode imposition shaft.
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Specification of the phase composition of Portland clinker
Vávrová, Alžběta ; Dlabajová, Lucie (referee) ; Másilko, Jiří (advisor)
This bachelor thesis deals with the determination of the phase composition of portland clinker and its optimization. The X-ray fluorescence spectroscopy, X-ray diffraction analysis and optical microscopy were used to solve this task. In the experimental section, X-ray fluorescence spectrometry results were used to calculate the potential phase composition of the clinker using the Bogue method. Then the X-ray diffraction analysis followed, it was used not only to determine the phase composition but also to determine amorphous content in the clinker. The microscope integration method was used to study the samples using optical microscopy. The obtained results were compared with each other and the main deficiencies of the individual methods were identified.
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Study of the dependence of concrete composition on the values of elasticity modules
Křížová, Klára ; Kolář,, Karel (referee) ; Adámek, Jiří (referee) ; Ďurica,, Tibor (referee) ; Hela, Rudolf (advisor)
The modulus of elasticity is one of the basic characteristics of concrete defining elastic deformation of concrete and it plays a significant role in the static design of structures. Due to current trends in concrete technology, offering a wide variability in the proposals of the composition of concrete, there are changes not only in strength characteristics but also in the modulus of elasticity of concrete. The aim of this doctoral thesis is to study the dependence of different compositions on modulus of elasticity of concrete. Design of concrete composition is prepared with respect to the use of different types of cement, mineral admixtures, types and fractions of aggregates. The work is mainly focused on the determination of static modulus of elasticity in compression with the addition of dynamic modules. In the first phase determined modulus of elasticity are compared with tabulated values according to Eurocode 2, which are derived for the specific strength class of concrete. Part of this work is the compilation of the main technological aspects of concrete which can favorably affect the modulus of elasticity.
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Development of chemically resistant sprayed mixture
Hermann, Radek ; Dohnálek,, Pavel (referee) ; Drochytka, Rostislav (advisor)
Production wastes for which a direct use in another production is found become secondary raw materials. There are several institutions in Czech Republic and in the world, which are currently dealing with the issue. This thesis deals with the issue of cementitious spray concrete mixtures and deals with the possibilities of using secondary raw materials and waste from production as partial replacement of binder and filler in these mixtures. The aim of this theses is to optimize the composition of additives in the recipe of the commercially produced pray mixture and to verify the influence of the degree of substitution of binder or filler by secondary raw materials on its physical-mechanical properties. The aim is to maintain or increase these properties while substituting the binder and filler as much as possible. After the evaluation of results, it is possible to say, by suitable optimization of the additives it is possible to achieve a significant improvement of the physical-mechanical properties of the mass and furthermore, from the results of this thesis follows, that by substitution of 100% fine filler in combination with substitution of 30% binder it is possible to maintain or increase the physical-mechanical properties after 28 days of curing and to significantly increase these properties after 90 days of curing. The results of this thesis are also related to the reduction of economic impact on production of the spray mixture, mainly due to the use of secondary raw materials.
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Cold recycling of flexible pavements
Řehulka, Martin ; Koudelka, Tomáš (referee) ; Varaus, Michal (advisor)
The bachelor´s thesis is focused on recycling of the flexible pavements in general, namely cold recycling. This modern technology was introduced in the Czech Republic after 1989. The first half of the thesis describes theoretically various types of recycling of flexible pavements, where the greatest attention is paid to this technology. The second part describes the section of the modernization D1 motorway where this cold recycling was applied. The technological process, including visual documentation and control tests, is documented.
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Cold recycling
Šperka, Pavel ; Stehlík, Dušan (referee) ; Hýzl, Petr (advisor)
Bachelor’s thesis focuses on the processing of knowledge of flexible pavements cold recycling, especially on the technologies if full depth reclamation and partial cold recycling in-place and the benefits or reasons for the increased use in the Czech Republic. In the practical part of the thesis the current status of selected sections, which were made by practical cold in-place recycling technology, is evaluated. In the end of the work the success of this technology is evaluated.
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