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Study of the influence of additions on the durability of aerated concrete
Halešová, Adéla ; Voves, Jiří (referee) ; Hubáček, Adam (advisor)
The aim of this work is to summarise and consider the possibilities of using admixtures and their influence on the durability of aerated concrete.This bachelor's thesis is based on research findings concerning aerated concrete. Furthermore, it deals with the study of inert and active additions. The experimental part is focused on testing trial samples with the addition of admixtures. It examines what is the rate of the possible chosen physically-mechanical features such as the rate of air density, the durability of surface against the effect of water and chemical defrosting substances and achieving the required strength.
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Geopolymers based on fly ashes and brick body
Řezník, Bohuslav ; Lang,, Karel (referee) ; Příhoda,, Jiří (referee) ; Žižková, Nikol (referee) ; Rovnaníková, Pavla (advisor)
In line with the current focus on utilizing side products of various production processes, this dissertation thesis analyzes the process of alkali activation of particular side products: fly ash and brick fragments. This activation produces geopolymeric materials widely used in civil engineering. The thesis aims to optimize the geopolymerization process so that the resulting geopolymer is both ecologically and economically viable. To that end, the thesis studies the course of geopolymeric reaction between the alkali activator and fly ash from: (i) the Chvaletice power plant, (ii) the Dětmarovice power plant, and (iii) biomass combustion, as well as (iv) fluid fly ash from the Hodonín power plant. All experiments of geopolymeric reaction have focused on the factors influencing the synthesis of geopolymers—that is: composition of the alkali activator, the ratio of alumino-silicate to the activator, and the impact of temperature on structure of the synthesized geopolymer. Further, the thesis analyzed the synthesized polymer’s microstructure, phase composition, resistance against corrosive conditions, and compressive strength, as well as mechanical-fracture properties of selected fly-ash geopolymers. The thesis finds that the most suitable for geopolymeric synthesis appears to be the fly ash from the Chvaletice power plant in which case the obtained geopolymers showed best properties in the studied areas. The fly ash from the Dětmarovice power plant, biomass fly ash, and fluid fly ash have failed to reach acceptable properties. Separately, the thesis studies the geopolymerization of brick body that could be suitable input for alkali activation. The geopolymers synthesized from brick fragments resulted in materials of supperior mechanical strength. A mixed use of fly ash and brick fragments failed to show a synergetic effect. Properties of the resulting geopolymers have been inferior to the properties of geopolymers produced using just fly ash or just brick body.
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Influence of waste glass in the alkali activated aluminosilicate
Novák, Václav ; Rovnaník, Pavel (referee) ; Bayer, Patrik (advisor)
Theoretical part of this work will be examine the most common materials from which geopolymers are produced and their alkaline activation and properties. In addition, the work will be examine glass itself and alkaline activation of glass. This paper also will be investigate possibilities of making geopolymers from glass or geopolymers with the addition of glass. In the experimental part geopolymers will be made and their basic material will be replaced with part of the glass. The mechanical properties and microstructure of these mixed geopolymers will be examined and how the glass influence the properties of these geopolymers.
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Properties of alkai-activated aluminosilicates subjected to high temperatures
Halasová, Kristýna ; Bayer, Patrik (referee) ; Rovnaník, Pavel (advisor)
Currently the concept of geopolymer or alkali activated aluminosilicate is very mentioned topic. Many studies concerning utilization of these materials have already been made, but if we want to use these materials in building industry in the future, further research will be needed. This thesis deals with the influence of high temperatures on alkali-activated slag, fly ash and metakaolin-based composites. The work compares mechanical and technological properties, microstructural changes and effect off iller on the geopolymer composites heated at 200–1200 °C. In conclusion, the individual properties are compared and application possibilities of these materials are evaluated.
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Application of metakaolin in refractory materials
Tvrdík, Lukáš ; Rovnaníková, Pavla (referee) ; Havlica,, Jaromír (referee) ; Kutzendőrfer,, Jaroslav (referee) ; Lang, Karel (advisor)
Refractory materials are irreplaceable in all industrial fields where it is necessary to use high temperatures. This paper deals with the use of metakaolin in refractory materials that allows the operation of such facilities. In recent decades has the development made significant progress in quality parametres, which extended life period of refractory materials in their use and significantly decreased the specific consumption of refractory materials in various technologies. This phenomenon is also called "harakiri effect". At the same time a constant pressure to the lowest prices of products is on the refractory market. Metakaolin seems to be appropriate raw material, which may help to achieve interesting qualitative effects. It may affect many properties of the influence on the behavior of materials during processing, through physico-mechanical parameters and dipping to the economic efficiency of production.
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The technology of aerated concrete
Koutný, Ondřej ; Repka, Martin (referee) ; Opravil, Tomáš (advisor)
Civil engineering is integral part of industry in each developed country. Naturally the construction point does not play the main role here, but also the material of building segments. In last fifty years the new possibility has been discovered against classic brick in form of autoclaved aerated concrete. This material gathers its customers not only due to low weight and easy application with sufficient strength, but particularly due to excellent heat-insulation properties. Contemporary trend in research of aerated concrete points to application of alternative raws, as for example metakaoline, to improve final properties of product by preserving of current technology and price.
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Study of Preparation and Properties of Historic Mortars
Majerová, Jana ; Lang,, Karel (referee) ; Fridrichová, Marcela (advisor)
The diploma thesis is concerned with study of preparation and properties of historic mortars. In theoretical part, there is summarized the historic progress of mortars and their material composition. The experimental part is focused on proposition of mortar mixes. The diploma thesis referring to actual research on Institute of Technology of Building Materials and Components, FCE VUT in Brno. The base mixe of historical mortar came from this research. In experiment, there is the base mixe of historical mortar modified with gypsum. In the first phase of the experimental part the basic technological and aplication properties are assessed. The second phase of the experimental part is focused on the course of hydration of the binder in different environments and subseqeunt determination of the phase composition by X-ray diffraction analysis. The aim of the thesis is to determine the optimal amount of gypsum and to optimize the recipe of historical mortar.
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