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Utilization possibilities of industry gypsum and secondary materials containing for preparation of composites
Weiglová, Jana ; Šoukal, František (referee) ; Opravil, Tomáš (advisor)
The work studies the possibilities of the utilization of secondary raw materials produced by power industry. It addresses mainly the gypsum by-products and fluidized coal combustion ash. As for the secondary raw materials the content of sulphites is observed and the dependences of their transformation to sulphides via natural oxidation by air oxygen or by addition of adequate oxidant are studied. The work follows with describing the effect of sulphides contained in raw materials on the mechanical properties of composites prepared from several various matrices such as alumina or portland cement, lime or portland clinker. As for pure portland clinker the ability to retard the setting is also observed. The amount of contained sulphites is measured volumetrically via indirect titration of iodine surplus by sodium thiosulphate with the starch size as the indicator.
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Lightweight composites based on fluid filter ashes
Palovčík, Jakub ; Másilko, Jiří (referee) ; Opravil, Tomáš (advisor)
This Bachelor’s thesis deals with preparation, study and analysis of binders based on fluid filter ashes. Binders were doped with various additives to alter the rheological properties, reduce volumetric weight and increase flexural compressive and tensile strength. Next, a possibility of using waste polyester fibres for reinforcement in matrices based on above mentioned binders was determined. The prepared samples were tested for compression and flexural strength after 28 days. Phase composition was analysed by means of X-ray diffraction analysis.
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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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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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The effect of fly ash on the properties of cement mortars.
Bayer, Petr ; Brandštetr, Jiří (referee) ; Šiler, Pavel (advisor)
The consumption of the cement for construction industries is increased every year. That is associated with greenhouse gas emissions, especially carbon dioxide CO2. Reduction of greenshouse gas emissions can be achieved by maximisation of the use of cementitious and pozzolanic by-products. As by-product could be used blast furnace slag and fly ash. My bachelor’s thesis is focused on the possibility of the partical replacement of the cement by fly ash. High temperature and fluidized fly ashes will be tested. The goal is to examine the behavior of the cement mortars in compensation of 10, 20, 40 and 60 % by weight of cement by fly ash. The compressive and flexural strength and isoperibolic calorimetry measurement were performed.
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Supersulphates cements
Mohelská, Lucie ; Wirthová, Michaela (referee) ; Opravil, Tomáš (advisor)
The work is studying posibilities of use secondary materials produced by energetical industry. In fact it studies posibilities of preparing supersulphates cements with secondary raw materials. Its main system for simulation was used milled portland clinker. To clinker were added diferent secondary raw materials from energetical industry with sulphate. On prepared samples were watched mechanical properties in time. Tested were different samples of secondary raw materials.
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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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