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Effect of partial replacement of Portland cement by diatomaceous earth on selected parameters of cement mortar
Rousková, Jana ; Sedlmajer, Martin (referee) ; Rovnaníková, Pavla (advisor)
The subject of this thesis is selected parameters cement mortars with partial replacement of Portland cement diatomaceous earth. This work provides information on the basic properties of diatomaceous earth and its deposits with a focus on deposit in Borovany. From the properties is very important pozzolanic activity due to the high content of amorphous silica of this soil. The main use of diatomaceous earth is in the area filtration and is used widely as a nutritional supplement. In the building industry, diatomite can be applied as an admixture to mortar and concrete, where it can, with its abilities, improve some physical mechanical properties. In the experimental part was diatomaceous earth, in its raw and calcined form, tested as admixture for cement pastes and mortars. The main criterion for evaluating these composites was bulk density, flexural and compressive strength. It was also investigated mineralogical composition, microstructure, freeze–thaw resistance and sulfate resistance.
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Incombustible ligtweighting agents for brick body
Suk, Vojtěch ; Stančík,, Hynek (referee) ; Sokolář, Radomír (advisor)
This diploma thesis deals with the possibility of reducing the density of the brick body using the chemical additive Vuppor for different types of soil, which are used for the production of thermal insulating products such as type THERM. Describes the availability of suitable additives (starch, carboxymethylcelullose, acrylic dispersion) that are capable of combining with the additive Vuppor to improve the observation properties.
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Investigation size effect of negative active mass additive on service life lead-acid accumulator.
Mikoláš, Jiří ; Novák, Vítězslav (referee) ; Bača, Petr (advisor)
The task of research work is to study new mechanisms and to minimize disturbance of lead batteries for hybrid electric vehicles. Those arising under the PSoC (Partial State of Charge) and is linked to irreversible sulphation mainly negative electrodes. As one solution to prevent sulphation of the negative electrode appears to be the active ingredients in a negative matter. In the investigated electrodes is verified the influence of carbon, titanium dioxide and silica on the grain size of the order of nanometers.
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Design and development of the electrostatic precipitator
Kvasnička, Karel ; Radil, Lukáš (referee) ; Ptáček, Michal (advisor)
This bachelor thesis deals with the design of an electrostatic precipitator and familiarization with the problems of separation on these separators. The aim of this work is to construct a functional model of an electrostatic precipitator. The principle of operation and design will be described. In addition, the design of a separator is elaborated, which was subsequently realized and experimentally verified in the CVVOZE Power Laboratories Research Infrastructure. The first part deals with the description of the legislation on air protection, the most frequent input material of separators and descriptions of the basic types of separators. In addition, the electric separator, its area of use, construction and individual components, as well as the undesirable operating state of the separator, are further elaborated. In the second part are presented the equations and calculations for the design of the separator. In the next part, the separator designer and his laboratory tests are described. The separator was subjected to basic voltage tests from the viewpoint of its operating voltage. Its functionality fits the realized experiments up to 30 kV. On the basis of this work and the production of the equipment, it is possible in the future to test the properties of flue gases and other gases.
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The possibility of using admixtures for waterroof concrete
Roháček, Lukáš ; Voves, Jiří (referee) ; Hubáček, Adam (advisor)
Bachelor thesis is mainly focused on additions, that have impact on water impermeability and other properities of fresh and hardened concrete. This issue is also described in short section, which is took from foreign reaserch. Thesis further discusses about the standards and regulations that determine, what properties should have waterproof constructions. Experimental part is showing influence of fly ash, slag and silica fume on conzistency, hydratation heat development, strenght, water impermeability, frost resistance and volume changes of the concrete.
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Study of possibilities of activation of power plant fly ash as an active ingredient in concrete
Máša, Jiří ; Uher, Vojtěch (referee) ; Hela, Rudolf (advisor)
Global concrete production is increasing, which brings some environmental burden. A certain solution is the use of secondary raw materials, which has been a long-standing practice in the construction industry. One of the most widespread secondary raw materials is power fly ash. However, in recent years trends have been directed towards maximizing their utility properties. The aim of this work was to study the possibilities of activation of power plant fly ash as an active admixture in concrete. The thesis is divided into two parts, the theoretical and the practical part. The theoretical part describes in detail the possibilities of power plant fly ash activation for use as an active admixture in concrete. The practical part of the thesis is focused on mechanical activation, where the knowledge of the theoretical part is verified on various fly ash.
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Optimizing the composition of micro concrete admixtures.
Juříková, Denisa ; Křížová, Klára (referee) ; Hela, Rudolf (advisor)
The aim of this paper is to summarize knowledges related to the use of fine-grained admixtures in cement composites. By utilizing of these admixtures it is possible to achieve extreme properties, especially high strenght and durability of concrete. These properties can be achieved by optimizing the density of the binder and filler in range of 0 to 0,25 mm. Therefore, large part of thesis is focused on admixtures and its effect on concrete. The experimental part of the thesis deals with optimization od selected admixtures in combination with cement to achieve the minimum of the voids and their compressive strenght were determined at 1, 3, 7, 28 and 60 days.
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Verification of durability of ash concrete in the environment XF
Kušiak, Petr ; Hela,, Vlastimil (referee) ; Hela, Rudolf (advisor)
Fly ash is now much used as an admixture to concrete. This master´s thesis focuses on the use of fly ash as an active admixture in concrete environment for XF. The thesis has two parts. The first part collected theoretical information about the origin and behavior of fly ash in fresh and hardened concrete. In the second part was experimental verification of these characteristics. The purpouse of this thesis is to demonstrate that the fly ash attribute to meet all environmental XF.
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Concrete with fly ash for XF3 and XF4
Máša, Jiří ; Ťažký, Martin (referee) ; Hela, Rudolf (advisor)
This bachelor thesis deals with concrete using fly ash as an active ingredient for environment XF3 and XF4. Bachelor thesis is divided into two parts. The first, theoretical part, is focused on basic information on power generation of fly ashes and solves the existing knowledge about concrete with partial asphalt replacement and then evaluates their properties both in fresh and condensed state. Below are the world-wide knowledge of the behavior of these concrete. The second part deals with the experimental verification of these findings contained in the theoretical part. The aim of this work is to verify the durability of concrete with fly ash for XF3 and XF4 environments.
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Study of the concept of K-value and efficiency index for fly ash and slag and their assessment and determination for concrete
Šperling, Petr ; Hela, Rudolf (referee) ; Hubáček, Adam (advisor)
This bachelor thesis deals with the use of active admixtures as a substitute for cement in concrete, specifically power plant fly ash and blast furnace slag. When using power plant fly ash and blast furnace slag as a substitute for cement in concrete, it is necessary to know their effect on concrete and to assess the different properties compared to concrete in which these admixtures are not used. This work will summarize the existing knowledge of the properties of power plant fly ash and blast furnace slag and their effect on fresh and hardened concrete. Furthermore, the possibilities of determining the efficiency index and the so-called k-value concept, which are used to assess the effect on cement mortar and concrete when replacing cement with an active admixture, will be summarized. In the experimental part, emphasis will be placed on determining the k-value. This is described in European technical standards in a very general way and is not sufficiently detailed for specific active ingredients.
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