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The optimization of melting as a decomposition process for material analysis.
Ptáček, Martin ; Koplík, Jan (referee) ; Šiler, Pavel (advisor)
Fusion is the process in which the sample particles are dissolved in the flux. This is used for the decomposition of substances which under normal conditions do not decompose in acid. For example, silicon, which is a substantial part of cement, is not degraded under standard conditions, so it is fused. Fusion may be in solution or in a pearl. Solution fusing is used for ICP-OES rather than XRF pearls. In addition to the pearl, XRF can also be measured in powder, but it is less accurate. This bachelor thesis deals with decomposition of standards and comparison of measured values with certified values. In the course of the work, samples of the standards were decomposed using several types of fluxes, measured at ICP-OES. The same standards were measured using XRF in the form of pearls. In addition to these two methods, elemental analysis of sulfur content was also performed. These methods were finally compared. From the measured data we can say that the best results are achieved with the ICP-OES method.
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Influence of calcium sulphate type on hydration of Portland cement
Šimčíková, Ivana ; Šiler, Pavel (referee) ; Šoukal, František (advisor)
My bachelor thesis deals with the study of the influence of calcium sulphate types on the hydration of Portland cement. Hydration is performed at 15 °C, 25 °C and 40 °C. In the theoretical part we find a description of the hydration of Portland cement and the influence of the type and amount of gypsum on the hydration period. The experimental part contains the preparation of samples for measurement and the principle of calorimetry including a description of the calorimetric curve. The data obtained from the calorimetric curve was processed into ternary diagrams for illustration. The diagrams show that the more calcium sulphate is soluble, the shorter the induction period, the times of reaching the minimum heat flow and heat flow at the maximum silicate peak will have. Further, the diagrams showed that as the amount of water in sulphate increases, so does the amount of hydration heat released.
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The optimization of quarried limestone analysis and usage.
Sidelnicov, Vitalii ; Bednárek, Jan (referee) ; Šiler, Pavel (advisor)
Limestones are rocks formed predominantly from the mineral calcite. The Czech Republic is quite rich in this type of rock. Limestone may have a very diverse composition, properties and uses. For this reason, it is beneficial to study and analyze this material, to better utilize it to its full potential. This bachelor thesis deals with the possible uses of limestone from Lesní lom in Líšna in the city of Brno, which consists of two limestones - Hádsko-Ričský and Vilemovický. Limestone analyses were performed using by the following analytical methods: XRF, XRD and ICP-OES. Furthermore, the thesis deals with the preparation of samples for individual analytical methods and the differences of the results obtained by individual methods. Part of the thesis is also an overview of the possible uses of analysed limestones.
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Improving of dispersion of silica fume in high performance concrete
Janča, Martin ; Koutný, Ondřej (referee) ; Šiler, Pavel (advisor)
The goal of this work was to create a method for improving the dispersion of silica fumes for use in high performance concrete. Traditional methods used to design and manufacture high performance concrete emphasize the removal of coarse aggregates. Use of specially sorted fine aggregates at relatively low doses, the use of super-plasticizers and siliceous excrement. The low water content was achieved by using superplasticizer on a polycarboxylate basis. The standard ultrasound technology found in each laboratory was selected for the dispersion of silica fume. For experiments were we used dry silica fume powder and aqueous stabilized suspension. For comparison, were prepared different mixtures which showed the effects of the treatment prior to the use of silica fume.
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The influence of aggregate on the properties of high performance concrete.
Bezděk, Ondřej ; Krátký, Josef (referee) ; Šiler, Pavel (advisor)
This bachelor thesis is focused on the influence of aggregates on the mechanical properties of high-performance concrete. The flexural strenght and the compressive strenght were observed after 1, 7 and 28 days. The process of hydratation was monitored using isoperibolic calorimetry. Laser particle size analysis of aggregates was also performed. As materials were used: Portland cement CEM I 42,5 R-Sc Mokrá, finelly ground silica sand, calcinated bauxite, fine test sand ČSN EN 196-1, medium test sand ČSN EN 196-1, rough test sand ČSN EN 196-1 and polycarboxylate superplasticizer Glenium Ace 40.
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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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Changes in some physical properties of the aqueous suspension of corundum powder during ultrafine grinding
Šuleková, Nikola ; Šiler, Pavel (referee) ; Svěrák, Tomáš (advisor)
This thesis is focused on the study of changes in properties of the aqueous suspensions of corundum during ultrafine grinding without and with the addition of grinding activator. Such studies are an important step in optimizing the grinding process properly, because by measuring physical properties of a particulate substance, it is easy to determine the actual fineness of the ground substance and its quality for further processing. For the measurement of granulometry, zeta potential, rheological behavior and turbidity, corundum suspensions in distilled water were prepared in a 1:5 ratio without the addition of grinding activator and with the addition of triethanolamine (TEA), by using a planetary mill. The suspensions showed pseudoplastic behavior and the zeta potential of all samples ranged between -30 and 30 mV, thus the suspensions were rather unstable. During the grinding, the viscosity and turbidity of the samples increased. TEA was not proved to be a suitable activator for wet milling of corundum because of higher degree of fineness achieved during milling without an activator.
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The study of zinc influence on Portland cement hydration.
Ptáček, Martin ; Janča, Martin (referee) ; Šiler, Pavel (advisor)
The topic of this work is the monitoring of the effect of zinc on the hydration process in Portland mixed cement (specifically with the addition of finely ground granulated blast-furnace slag, high temperature fly ash and fluidized bed combustion filter ash). How much zinc and at what time it remains in the pore solution during hydration. Activation energy of a mixture of cement with zinc in the form of soluble salts (Zn(NO3)2.6H2O and ZnCl2) and insoluble oxide (ZnO) by isothermal calorimetry was also investigated. The XRF method has shown composition during hydration. The zinc retardation effect was investigated by isothermal calorimetry and activation energy was calculated using this method. The XRF and ICP-OES methods were used to measure the zinc content of the pore solution. And the amount of portlandite was monitored by the DTA and XRF method.
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Preparation of yttrium based chemically bounded phosphate ceramics
Uher, Samuel ; Šiler, Pavel (referee) ; Švec, Jiří (advisor)
The thesis is focused first on the research of literature on the topic of phosphate ceramics and then on the search for a suitable synthesis of phosphate binder based on Y2O3-P2O5-H2O and characterization of the resulting products. Various types of syntheses were prepared with subsequent characterization of the phase and chemical composition of the final products. The samples were measured on an electron microscope to determine their surface morphology and also element maps were obtained. The samples were also analyzed by heat microscopy to determine the temperature behavior of the samples. After measurement on a heat microscope, the samples were measured again on an electron microscope, in order to detect changes caused by the action of high temperatures, in particular to assess the presence of binder or sintered phases.
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Self-leveling floors based on secondary raw materials
Darakevová, Michaela ; Šiler, Pavel (referee) ; Opravil, Tomáš (advisor)
The work deals with the use of secondary raw materials in the self-leveling floor systems when used as a secondary raw material perform here especially classic ash, boiler slag and gypsum from flue gas. Work is looking for ways in as much as possible to replace conventional materials used in self-leveling flooring systems, secondary energy products. The aim of this work is to determine the optimal amount and ratio of secondary raw materials in self-leveling flooring compounds so that they are maintained or improved standard properties of these compounds reported in the standards. The work is divided into several points, the first point was first sought appropriate composite binder, where it was used as aggregates reach a standard sand. At other points the sand was then replaced by secondary materials. Were also tested ingredients to influence the rate of cooling, or for the onset of the initial strength.
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