National Repository of Grey Literature 54 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Effect of ground limestone addition on properties of cement-slag binder systems
Bílek, Vlastimil ; Másilko, Jiří (referee) ; Opravil, Tomáš (advisor)
This thesis deals with the effect of ground limestone addition on properties of cement-slag binder system. The evolution of compressive and flexural strength of binary and ternary systems (pastes), where 25 % of cement was substituted by one or two admixtures in different ratio, were determined and mutually compared. Granulated blast furnace slag and three different limestones were these admixtures. Two of that limestones were natural and one was prepared by a precipitation. For comparison, mixtures, where ash was added insted of slag, were prepared. The mechanism, by which finely ground limestone participates in hydration process, was studied by conduductometric measurements of systems simulating conditions in fresh pastes, and by TG-DTA method, which was used to determination of added limestone amount which remains in its original form and the amount which participates in the formation of hydration products.
Possibilities of using yet unused secondary products from the production of titanium white
Smirnov, Pavel ; Másilko, Jiří (referee) ; Opravil, Tomáš (advisor)
Waste products are an integral part of any production. The production of titanium white is no exception. The bachelor thesis is aimed at finding an application for a secondary product, red chemogypsum which is obtained by neutralizing waste sulfate water. The thesis aimed to find a suitable application for chemogypsum in the construction industry using experiments. The calcium sulfate dihydrate was processed by drying into monohydrate, which is the basic raw material of many products. Furthermore, the composition of the material was determined. Its properties such as onset of solidification, compressive and flexural tensile strength were investigated. Gypsum plasterboards and lightweight and insulating boards were also made. This binder was also used in filling bricks with inorganic insulating material. The knowledge gained from this work can be used to further research and improve products and hopefully make realistic use of this hitherto deposited material in the future. The thesis also provides concrete examples and suggestions for the use of this secondary raw material.
Preparation of modified tricalcium aluminate phases and study of their hydratation processes
Vávrová, Alžběta ; Koplík, Jan (referee) ; Másilko, Jiří (advisor)
This diploma thesis deals with the preparation of modified tricalcium aluminate phases using sodium ions, and the study of their hydration processes and products. The X-ray diffraction analysis, isothermal calorimetry, laser diffraction, and scanning electron microscopy with energy dispersion analysis were used to solve this task. The preparation of modified tricalcium aluminate phases using high temperature methods has been described in the experimental section. Furthermore, the X-ray diffraction analysis was used to determine the purity of the prepared phases and the scanning electron microscopy with energy dispersion analysis was used to define the volume of sodium. Laser diffraction was used to measure a particle size distribution in the individual phases. Subsequently, hydration of the pure phases was performed in an isothermal calorimeter. It was followed by hydration of phases in the presence of different gypsum content and then in the presence of saturated portlandite solution. Hydration of some samples was stopped in order to better understand the hydration process. Hydration products were studied by X-ray diffraction analysis. The obtained results were compared with each other and the influence of sodium ions on both the structure of the prepared phases and the course of hydration and its products has been discussed. The effect of adding different volumes of gypsum and portlandite on the course of hydration of the individual phases was also compared.
Possibilities of using waste diatomaceous earth
Jonešová, Markéta ; Másilko, Jiří (referee) ; Opravil, Tomáš (advisor)
Waste diatomaceous earth is a by-product generated during a production of diatomaceous earth for filtration. It is a material with very specific properties, which has currently no use other than backfilling of mining areas. For this reason, this Bachelor thesis deals with exploration of potential utilization possibilities of this remarkable material. Analysis of the waste diatomaceous earth will be carried out, and the chemical and physical properties will be determined. During experimental part, a set of calcination tests will be carried out and evaluated with focus on properties of the waste diatomaceous earth, which could be significantly increased by the calcination process. For example, a pozzolanic activity could be significantly affected.
Specification of the phase composition of Portland clinker
Vávrová, Alžběta ; Dlabajová, Lucie (referee) ; Másilko, Jiří (advisor)
This bachelor thesis deals with the determination of the phase composition of portland clinker and its optimization. The X-ray fluorescence spectroscopy, X-ray diffraction analysis and optical microscopy were used to solve this task. In the experimental section, X-ray fluorescence spectrometry results were used to calculate the potential phase composition of the clinker using the Bogue method. Then the X-ray diffraction analysis followed, it was used not only to determine the phase composition but also to determine amorphous content in the clinker. The microscope integration method was used to study the samples using optical microscopy. The obtained results were compared with each other and the main deficiencies of the individual methods were identified.
Options of preparation of tobermorite
Dlabajová, Lucie ; Másilko, Jiří (referee) ; Opravil, Tomáš (advisor)
The bachelor thesis deals with options of preparation of tobermorite. Tobermorite is a mineral, which, thanks to its composition and properties, is an important phase in aerated concrete. On the field of science and research, an attention has been drawn on tobermorite as an ion ex-changer. Synthesis of a pure mineral can cause problems with testing and improving its properties. Tobermorite crystallizes together with other calcium silicate hydrates from system CaO-SiO2-H2O during a hydrothermal reaction. This thesis mainly focuses on influence of choosing starting materials and their treatment before the hydrothermal synthesis. Other influences which are studied are conditions of hydrothermal processes and their influence on final products of hydrothermal synthesis. Phase composition of prepared samples was characterized by XRD and TG-DTA. As an additional analyze was used scanning electron microscopy (SEM).
Investigation of portlandite carbonation using the in-situ X-ray diffraction analysis
Růžička, Lukáš ; Koplík, Jan (referee) ; Másilko, Jiří (advisor)
Thesis deals with carbonation of portlandite using in-situ X-ray diffraction analysis. The carbonation of portlandite progress in concrete structures and it is already quite widely discussed. It is responsible for corrosion and degradation of reinforced concrete elements, and thus its influence is perceived very negatively. The main goal of this work is to determine the ideal conditions for the progress of carbonation of portlandite. In this work the progress of carbonation depending on the relative humidity and temperature was observated. The amount of carbonated portlandite was evaluated by means of thermal analyzes (TG / DTA) and X-ray analysis.
Preparation and characterization of magnetic nanoparticles modified by surfactants
Solnička, Ondřej ; Másilko, Jiří (referee) ; Enev, Vojtěch (advisor)
Theme of this bachelors thesis was preparation and characterization of iron(II, III) oxide nanoparticles. Those nanoparticles were modified by surfactants. The surfactants which were used for modifiation were CTAB, TTAB and Septonex. Prepared and modified nanoparticles were taken for characterization by using methods of elemental analysis, thermogravimetry, dynamic light scattering and transmission electron microscopy (TEM). Results from each measurement shows that nanoparticles modified by CTAB had on average 85.9 nm in diameter, TTAB size was on average 108.3 nm and the last nanoparticles with Septonex had 246.6 nm in diameter on average. Prepared modified nanoparticles except the Septonex ones were stable enough to not aggregate. Septonex modified nanoparticles had greater tendenty to aggregate.
Possibilities of utilization of boiler slag
Fialová, Gabriela ; Másilko, Jiří (referee) ; Opravil, Tomáš (advisor)
This bachelor thesis studies the boiler slag (slag) and its potential use in refractory materials industry. It concentrates its on chemical and mineral composition. Mullite parts and Fe2O3 probably lowers the melting point and heat resistance. During the work is proposed and experimentally validated a method for reducing the content of iron in the slag shares.Is observed the effect of the reduced number of iron units for the heat resistance of the material. The results are further processed and assessment. Thermal resistance was monitored using incandescent microscopy.
Possibilities of utilisation of salt slags from aluminum production
Sedlačík, Martin ; Másilko, Jiří (referee) ; Opravil, Tomáš (advisor)
Bachelor thesis deals with characterisation of salt slag formed during melting of aluminium scrap in rotary furnaces and proposes options of utilization of this material as a secondary raw material. Samples from top, middle and bottom part of mould, where slag cools down after the melting process is finished, were tested. Aim of the thesis is also to evaluate the effect of air access during the cooling process on phase and chemical composition of salt slag. Particle size distribution, content of soluble substances and composition were examined in collected samples. Phase and chemical compositions of both soluble and insoluble portion of idividual fractions were determined using X-ray powder diffraction and X-ray fluorescence spectrometry.

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