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Possibilities of application of fluidized bed combustion solid residues from municipal waste
Melicher, Daniel ; Solný, Tomáš (referee) ; Opravil, Tomáš (advisor)
The bachelor thesis deals with the use of solid residues from incineration waste products, especially in the construction industry. The aim of the thesis is to test various modifications of solid residues from incineration waste. These secondary materials were tested in bonding systems based on hydratation of portland cement, gypsum made from chemogypsum, quicklime and alkali-activated systems. The aim was to verify whether solid residues from waste incineration could be used as a component of alternative materials for the construction industry.
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Development of phase composition in silicate systems by available methods and their optimalization
Opravilová, Lenka ; Palou, Martin (referee) ; Škvára, František (referee) ; Havlica, Jaromír (advisor)
One of the most prominent measurable parameters of the development of phases and phase transformations in inorganic systems are undoubtedly the volume changes of silicate matrix. The study of volume changes is crucial in the terms of usable durability of final product. They represent shrinkage or expansion of the material and may lead to significant decrease of technological and ecological parameters and often to complete destruction of these materials. Most often the volume changes can be observed when cement is used as a binder and in concretes, mortars, artificial aggregates and other similar materials. There are many methods to detect, define and determine the volume changes qualitatively or quantitatively. The development of phases was investigated as a part of the dissertation thesis and hence the volume changes were observed under the conditions closest to the real state in the construction industry. The raw materials and admixtures were selected which model the content of hazardous components present in conventional materials (both natural and secondary), used in construction and the relationship with volume changes was searched and demonstrated. The contacts for measuring the volume changes were attached to test surfaces of specimens and the physical - mechanical tests (volume changes, phase changes, strength, etc.), chemical analysis and ecotoxicity tests depending on the length of hydration were performed.
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Effect of pH of mixing water on hydration and mechanical properties of cement composites.
Bezděk, Ondřej ; Krátký, Josef (referee) ; Šiler, Pavel (advisor)
This master’s thesis is focused on the effect of mixing water pH value on hydration and mechanical properties of cement composites based on portland cement. Source material was CEM I 42,5 R. Hydration process was analyzed by isoperibolic calorimetry, X-ray diffraction analysis and differential thermal analysis. Compressive and flexural strength was examined as mechanical properties. The samples microstructure was observed by scanning electron microscopy. Influence of mixing water pH value on flexural and compressive strength, retardation of hydration and ratio of individual phases was shown.
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The influence of zinc oxide on the cement composite with silica fume.
Dobiáš, Jiří ; Koutný, Ondřej (referee) ; Šiler, Pavel (advisor)
The aim of this work was to investigate the influence of zinc oxide on the properties of blended Portland cement mixed with silica fume. On the pastes were monitored flow properties and by using of isoperibolic calorimetry process of the hydration. On the prepared samples were studied mechanical properties of obtaining values of compressive and flexural strength after 1, 7 and 28 days. By using of XRD were measured phase composition and microstructure development war observed by SEM. The elemental composition of cement leaches was measured by using of ICP-OES.
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The effect of boron and its compounds on setting time of portland cement
Kratochvíl, Jiří ; Švec, Jiří (referee) ; Opravil, Tomáš (advisor)
The aim of this work is to study the influence of boron and its compounds, boric acid and borax, on hydratation of portland cement. The first part describes chemical composition of portland cement and reactivity of its components. The second part deals with hydratation of portland cement. The teoretical part ends with description of retardation of portland cement using gypsum or other sulphate options. The experimental part describes preparation of samples – cement paste – modified by addition of boron, boric acid and borax in diferent concentrations. Results are obtained by evaluation of calorimetric curves, mechanical properties and phase composition. The goal is to describe kinetics of targeted slowed down process of hydratation and to find such addition which would suspend setting of boron modified system entirely. Comparison of effects of each boron-containing compound is based on its concentration and on its kind.
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The influence of hydration accelerators on cement doped with zinc
Beneš, Pavel ; Šilerová,, Iva (referee) ; Šiler, Pavel (advisor)
Zinc in cement has negative properties mainly due to a significant delay in hydration. This bachelor thesis deals with the study of hydration of cements containing zinc. The course of cement hydration was monitored by isoperibolic calorimetry. Zinc was doped to CEM I 42.5 R in the form of 1 weight percent zinc oxide. Calcium oxide, formic acid and calcium formate were used in various proportions as accelerators. The obtained results were compared with the measured strengths and finally the suitability of the given accelerators was discussed for use in construction application.
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Study of the properties of the ettringite which was produced synthetically
Hučínová, Lenka ; Jiroušková, Kateřina (referee) ; Fridrichová, Marcela (advisor)
Up to present, ettrigite has been prepared by two means in the Institute of Technology of Building Materials and Components of the BUT Faculty of Civil Engineering: originally by the hydration of the yeelimite clinker; recently by the direct synthesis of ettringite from calcium hydroxide and aluminum sulfate, the latter being considered more suitable in qualitative and quantitative terms. This diploma thesis focuses on the comparison of both means, using ettringite produced by the latter as control sample. This endeavor focuses on monitoring the stability of ettringite and its possible conversion to other minerals using X-ray diffraction analysis, thermal analysis and scanning electron microscopy (SEM).
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Study of new types of admixtures for waterproof concrete
Sikorová, Věra ; Másilko, Jiří (referee) ; Kalina, Lukáš (advisor)
This bachelor thesis is focused on the influence of crystallizing admixture for waterproof concrete. Reference concrete samples and modified concrete samples were prepared with different dosing of the crystallizing admixture, on which the standard test – the depth of penetration of water under pressure was carried out. The rheological properties of fresh concrete were verified by a slump test. The mechanical properties of the hardened concrete were examined by a compressive strength test. The mechanism of effect of the crystallizing admixture has been studied by scanning electron microscopy and X-ray diffraction analysis.
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