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Composite materials based on alcali activated blast furnace slag with admixture of fly ash
Indra, Ivo ; Brandštetr, Jiří (referee) ; Opravil, Tomáš (advisor)
This thesis concerns on substitution of blast furnace slag or its part with fly ash in alkali-activated systems based on aluminosilikates. Classic, fluid bottom and fluid filter fly ashes will be tested. The goal is to prepare geopolymer with required mechanical properties, but with maximal admixture of alternative raw materials. In composites with substitutioned slag or its part the thesis focuses mainly on workabilityof fresh mixture, pressure and bending strenght. Use of secondary raw materials has advantages in the economic point of view and it´s friendly to enviroment, too.
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Determining the possibilities of increasing binding potencial of fly ash for the usage in cement composites
Jančaříková, Denisa ; Ďurica,, Tibor (referee) ; Klečka,, Tomáš (referee) ; Kulísek, Karel (referee) ; Hela, Rudolf (advisor)
The deliberate use of fly ash in the production of concrete has been used for decades, but recent trends tend to maximise its utility properties. These are different types of activations from chemical through thermal to mechanical. An alkaline agent is added to chemical activation which, by etching the glass structure of the ash grain, promotes its reactivity. Mechanical activation is mainly focused on granulometry and particle size distribution curve. In this thesis three mechanical activation methods are compared: separation the ash into fractions by grain size, mixing these fractions to achieve the ideal particle size distribution curve and grinding. Four types of ash were collected from the Tušimice power plant – ash from individual electrostatic separators (I, II and III) and SESYP ash which represents the total volume of production. Ash from individual separators differ not only in the particle size but also in the chemical composition and reactivity. Better properties generally have smaller ash particles. This is used by mechanical activation by sorting. When mixing the individual ash fractions, the aim is to achieve an optimal grading curve of either the ash itself or the fine particle set in the concrete. In this work, ash is only used to calculate the mixing ratio and the grading curve according to Funk was selected as optimal. The last compared option of activation was grinding ash. Grinding was carried out in an industrial mill for 15, 30, 45, 60 and 75 minutes. The efficiency of the modified ash was monitored for cement paste in terms of rheology and for concrete in terms of consistency, strength and durability. Based on the results we can say that mechanical activation by sorting is suitable for special purposes, but it’s necessary to realise that coarser ash fractions remain unused. When mixing the fractions to ensure matrix density, the efficiency was shown mainly on the durability characteristics. Grinding cause positive effect.
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Continual helicoidal mixer
Radoš, Pavel ; Malach, František (referee) ; Malášek, Jiří (advisor)
This work contains a proposal for constructions and workings of a worm mixer of clay, lime, cementand fly ash with water for delivery quantity 18 tons per an hour. The introduction describes problems of mixing and mixers in the preparation of building materials. I have mentioned calculation of the main proportions and drive under the relevant norms and self-fortress control of the stresssed parts of mixer. Drawing documentation is worked into the ACad program and contains the configurations of the proposed machinery and detailed subassembly of important parts of worm mixer.
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Pipe screw conveyor for fly ash transport
Žaloudek, Vilém ; Zeizinger, Lukáš (referee) ; Škopán, Miroslav (advisor)
This bachelor's thesis deals with design and constructional solution of oblique tubular screw conveyor for transportation of power plant ash from silo to further technological processing. In this thesis evaluation of fundamental dimensions, design of power unit, design of bearings, evaluation of filling of the through and strength control of selected components of screw conveyor is done. This thesis consists of evaluation report and drawing documentation.
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Continual helicoidal mixer
Pelka, Tomáš ; Malach, František (referee) ; Malášek, Jiří (advisor)
This diploma project works out and is focused on the continual mixing process of the particular matters. The project is divided into following chapters. Chapter 1 includes mixing theory and information of the experimental work of the particular matters for blade using. In chapter 2 there is Evaluation and calculation of the technical parameters for the mixer. Chapter 3 deals with the engine proposal and chapter 4 includes calculation and design work of the gear transmission. Chapter 5 includes the stress analysis of the shaft and blade with the I-deas software. In attachment there are also the mixer arrangement drawing and detailed drawings of the key parts and groups for the mixer.
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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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The development of composites based on inorganic binders designed for the extreme applications
Janoušek, Petr ; Šácha, Libor (referee) ; Dufka, Amos (advisor)
The topic of this master's thesis is the development of composite materials based on inorganic binders for use in extreme conditions. It means especially geopolymeric or alkali activated materials (AAM) based composites. The theoretical part of this thesis summarizes knowledges about the development and use of alkali-activated materials, their structure and mechanisms of their formation. It also deals with the applicable raw materials for AAM and their exciters, which are in particular water glass and sodium hydroxide. There also have been a summary of the effects of high temperatures and chemicals on the mechanical properties of AAM and the requirements of standard EN 1504-3 for repairing materials. The task of the practical part was to develop a repair mortar for concrete structures based on AAM so that its production was as simple as possible, ie one-component materials. Gradually six recipes have been develeoped. Test specimens made from these recipes have been putted to selected tests according to the requirements of ČSN EN 1504-3.
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Pipe screw conveyor for fly ash transport
Žaloudek, Vilém ; Zeizinger, Lukáš (referee) ; Škopán, Miroslav (advisor)
This bachelor's thesis deals with design and constructional solution of oblique tubular screw conveyor for transportation of power plant ash from silo to further technological processing. In this thesis evaluation of fundamental dimensions, design of power unit, design of bearings, evaluation of filling of the through and strength control of selected components of screw conveyor is done. This thesis consists of evaluation report and drawing documentation.
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