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Application of fly ashes from fluid bed coal combustion within refractory materials
Kotrla, Jan ; Bartoníčková, Eva (referee) ; Šoukal, František (advisor)
The thesis deals with the possibility of utilization of fluid ash in refractory materials and its influence on resulting properties. This work studies the effect of bed and filter ash addition on properties of the droplet and resulting mechanical properties, bulk density, shrinkage and firing temperature of stove fireclay. The subject of this thesis is also reduction of SO2 emissions evolved burning of fireclay containing fluid ash rich of anhydrite. Emissions of SO2 were observed by TG-TDA-EGA method. Characterization of prepared samples and study of heat treatment processes was based on XRD, TG-DTA-EGA, TDA, SEM–EDS, heating microscope and isothermal calorimetry.
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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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Synthetic Preparation and Properties of Thaumasite
Klásková, Silvie ; Dvořák, Karel (referee) ; Fridrichová, Marcela (advisor)
This thesis continues in the monitoring of thaumasite thermodynamic stability. It mainly deals with mineral properties and possible ways of its synthetic preparation. Mineralogical composition determined using X-ray diffraction analysis as well as possible impact of sample storage conditions can help further property identification. Based on the obtained radiographs, thaumasite mineral can be well distinguished from the very similar ettringite mineral.
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Possibilities of alcali activation of steel slag
Frýbortová, Iva ; Rovnaník, Pavel (referee) ; Opravil, Tomáš (advisor)
The properties of alkali activated steel slag as a clinker-free binder system was studied in this thesis. The aim was to find the optimal composition of alkaline activator providing good properties of the prepared binder. Sodium and potassium hydroxides and alkaline silicates in the form of solutions and powders were used as the activators. Mixture of steel slag, fluidized bed coal combustion ash and water without any activating ingredient was another binder system studied in this work. Mechanical properties, such as compressive and flexural strength, of the mixtures were determined. Calorimetric measurements were used for the study of hydration process, scanning electron microscopy for the examination of microstructure.
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The effect of particles size on the properties of mortars.
Sehnal, Tomáš ; Krátký, Josef (referee) ; Šiler, Pavel (advisor)
The consumption of concrete as a building material is still increasing over the world. Concrete production is closely associated with CO2 and other greenhouse gases emissions. The reduction of these emissions can be achieved by a higher utilization of secondary raw materials in cement mixtures. This bachelor work is focused on the using of secondary raw material, finely ground granulated blast furnace slag and fly ash from fluidized bed combustion and high temperature combustion. The properties of milling pure cement and cement mortars with addition of secondary raw material will be measured. Compressive strength, flexural strength, and calorimetric measurement will be performed for these prepared mortars.
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Fly ash of class C for ceramic technology
Keršnerová, Lucie ; Šveda,, Mikuláš (referee) ; Rovnaníková, Pavla (referee) ; Všianský,, Dalibor (referee) ; Sokolář, Radomír (advisor)
This thesis is focused on the possibilities of the utilization of the fludized fly ash in ceramic technology, especially in the field of brick manufacturing and ceramic tiles. There were used fly ashes from thermal power plants in Hodonín, Ledvice and Tisová. Fluidized fly ash can be used for manufacturing of building materials. There hasn’t been done extensive research in this area. One of the problem is sulphur dioxide leakage during burning. The work describes the behaviour of fluidized ash during firing. The attention is focused on air pollution of sulphur dioxide. The production of SO2 is controlled so that the aim of the work is to find a way how to avoid leaking. It was proved that addition of sodium ions causes the formation of minerals hauyne and nosean during firing. Also is described the behaviour of the fly ash-soil mixtures. The anhydrite decomposition temperature is lower than in pure fly ash. In the end is fluidized ash applied for the production of dry pressed ceramic tiles. This ash can be used in ceramic technology. However, despite the interesting results there are number of problems that need to be solved.
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Economic aspects of environmental use of building materials based on secondary raw materials.
Ťažký, Tomáš ; Durica,, Tibor (referee) ; Sedlmajer, Martin (referee) ; Nosek,, Karel (referee) ; Kulísek, Karel (advisor)
The disses thesis is focused on usage of secondary raw materials from the electric power industry, specifically fly ash as a component for the building industry, concentrated on concrete. Two main streams are covered, environmental and economical. Reasons, which led to focus on the selected subject are coming mainly from the scarcity and availability of high-quality mineral resources, environmental pressure for usage of industry byproduct, reducing emissions and economical pressure to reduce production cost, especially raw materials. The main purpose of the work was to verify the possibility of increasing the usability of fly ash as a mineral additive in the technology of concrete production with materials retrieved from coal fired power plants and applying mechanical activation of fly ash. The main goal of the experimental part of work was to demonstrate improvement of fresh and hardened concrete properties as a main condition to support economic efficiency of mechanical activated fly ash. Base on previous facts the methodology was covering two main areas, the experimental and the assessment. Relatively large sets of tests were performed, using a wide range of tested high temperature fly ash and fluidized bed combustion fly ash granulometrically treated, by mixing and grinding. Results of the testing confirmed focused parameters for concrete and mortar mechanical properties, total economical efficiency of the targeted solution and the subject of the dissertation. In the experiment section has been retrieved valuable findings contributing to the overall knowledge of the faculty, also for the practical application. The results of the tests confirmed the achievement of the planned target parameters, both in terms of physical and mechanical properties of experienced mortars and concretes, as well as the overall economic efficiency of the proposed design and the topic of the disses thesis. Within the experimental work, valuable professional knowledge and benefits w
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Possibilities of recycling in the sand aerated concrete technology
Kostura, Patrik ; Kulísek, Karel (referee) ; Drochytka, Rostislav (advisor)
Waste of the aerated concrete is generated directly from the production of aerated concrete or from the constructions. The options for handling aerated concrete are two. We can deal with it as a light aggregate or as a material for the production of aerated concrete. Based on the physico-mechanical properties, the decision was made that aerated concrete is suitable as a light aggregate. The brash as a light aggregate was tested in two variants of the softness (0-2 mm, 0.25-2 mm). Evaluation of the brash as a suitable material for the production of aerated concrete consisted of the creation of laboratory-autoclaved composites. The brash was tested in different ratios (10%, 20%, 30%, 40%), two variants of fineness (0-2 mm, 0-0.25 mm) and two formulations (lime base, fluffy fly ash). Silicon sand was replaced. Based on physico-mechanical properties and microstructural analysis (XRD, SEM), was found that aerated concrete as a material is suitable for 40% sand substitution.
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