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Synthetic Preparation and Properties of Ettringite
Vlachovský, David ; Kulísek, Karel (referee) ; Fridrichová, Marcela (advisor)
The work is focused on properties and behavior of ettringite in relation to external environment conditions. It concentrates on the mineralogical composition of ettringite prepared by the method of direct synthesis of aluminium sulphate octadecahydrate and calcium hydroxide at various humidities. Depending on these factors, the formation of ettringite and its possible conversion to other minerals was observed.
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The thermodynamic stability of etringite
Magrla, Radek ; Durica,, Tibor (referee) ; Bílek,, Vlastimil (referee) ; Brauner,, Josef (referee) ; Fridrichová, Marcela (advisor)
The theoretical part of this doctoral thesis summarizes the current knowledge of portland cement and its manufacturing technology, information of FBC ash, Aft phases, AFm phases and the current knowledge of thermodynamic stability of ettringite. The practical part of the doctoral thesis focuses on manufacturing of ettringite based on yeelimite clinker, studying the influence of environment on thermodynamic stability of ettringite and manufacturing of ettringite by direct addition of calcium hydroxide and aluminum sulfate.
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The composites materials based on the solid residues of fluidized combustion
Kalina, Martin ; Koplík, Jan (referee) ; Opravil, Tomáš (advisor)
This bachelor thesis deals with a study of possible preparation of composite materials based on the solid residues of fluidized bed combustion. It focuses mainly on the strength properties of prepared materials and the phase composition of incurred hydration products. A powder X-ray diffraction analysis was used to determine the phase composition of prepared stiffened samples. Based on analysis of raw materials (fluid ash), various ingredients and additives were added to the mixtures in order to modify the composition or rheological properties of the fresh mixtures. After 28 days of maturation, the phase composition of prepared samples and the development of compressive and tensile strength in bending were monitored.
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Influence of ettringite formation on mechanical properties of zinc doped cements.
Kunovský, Ondřej ; Matějka, Lukáš (referee) ; Šiler, Pavel (advisor)
This bachelor thesis deals with the study of the effect of hydration accelerators in cement pastes doped with zinc ions. Their influence on hydration reactions, mechanical properties and the amount of ettringite formed was studied. CEM I 42.5 R cement was used and zinc was added in the form of ZnO in an amount of 1 wt. % of Zn relative to cement content. Strengths were measured over a time horizon of 98 days. In addition, analyzes by SEM, XRD and DTA methods were performed on selected samples to determine the amount of ettringite. It has been found that compressive strengths can also decrease during hydration. At this decrease, SEM, XRD and DTA showed a reduction in the amount of ettringite in the sample.
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Study of volume changes of binders silicate
Nováček, Jaroslav ; Rovnaníková, Pavla (referee) ; Steuer,, Radek (referee) ; Pavlík,, Zbyšek (referee) ; Šťastník, Stanislav (advisor)
In theory, this work is devoted to the principles and methods of measurement of volume changes of mortars and concretes. Emphasis is placed on cement self-levelling screeds with initial shrinkage compensation. In the practical part of the work is devoted to the development of prototype measuring system designed for non-contact detection of volume changes hydrating silicate. Using the new measurement method is also practically examined the influence of boundary conditions on hydration volume changes of selected silicate binders, cement mortar and cement levelling compound based on four different connective concepts. In the calculation, this work focuses on the numerical modelling of volume changes of the examined compounds.
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