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The study of hydration of RPC (Reactive Powder Concretes) in hydrothermal condition
Dvořáková, Tereza ; Koplík, Jan (referee) ; Šoukal, František (advisor)
The diploma thesis deals with the study of hydration of reactive powder concrete under hydrotermal conditions. The theoretical part describes the properties of materials and additives used for the preparation of mixtures. The following describes the principles and requiments for the materials for preparing the reactive powder concrete. The practical part is studied design method mix and the impact of materials to the consistency of paste. The effect of cample placement on flexural and compressive strength of the prepared mixtures was observed. The samples were stored under standart laboratory conditions and under hydrothermal conditions. The phase composition of the samples was monitored by X-ray diffraction analysis and the mocrostructure by scanning electron microscopy.
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Local tests of mechanical properties of materials
Wasserbauer, Jaromír ; Šoukal, František (referee) ; Zmrzlý, Martin (advisor)
This thesis deals with measurement of hardness and microhardness in relation to structure of homogeneous and heterogeneous materials. In the introduction basic theoretical background is commented, i.e. definitions, terminology, principles of measuring techniques for estimation of hardness, microhardness, tensile strength, compressive strength and bending strength. Follows a brief review of present research results focused on use of described principles in materials engineering. Then the experimental equipment and sample preparation is described. The crucial part of the thesis is summary of achieved results of original measurement and discussion of their relations to each other. Finally, the groundbreaking estimation is described, showing the correlation of chemical composition gradient and mechanical properties in interfacial zone of geopolymeric material.
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The influence of triaxial deformation of aggregates on properties of concrete
Fójcik, Tomáš ; Kalina, Lukáš (referee) ; Šoukal, František (advisor)
This diploma work takes focus in elastic modulus of unbound granular aggregates, which was determined by repeat load triaxial test and in deformation behaviour of unbound granular aggregates - elastic and plastic deformation. It was examine the propriety of this aggregate for its service as underlying granular material in pavement. Further, there was observed the influence of elastic modulus of unbound granular aggregates on concrete characteristics - compressive and bending strength. Finally, it was observed the influence of individual fractions of aggregates on its elastic modulus and strength of concrete.
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Preparation of geopolymeric binders for toxic metals inhibition
Jevická, Lucie ; Kalina, Lukáš (referee) ; Šoukal, František (advisor)
This thesis deals with preparation of geopolymeric binders for inhibition of toxic elements, especially arsenic. It studies influence of content progress of different phases in prepared binders on leachability of As during the setting. The aim of this study is to determine the type of inhibition or the cause of leachability of As in prepared binders respectively. Fly ash from high-temperature coal combustion, slag, cement kiln dust and sodium hydroxide solution were used for experimental works. FT-IR, TG-DTA, XRD analyses after different hydration times were used. The leachates were analyzed by ICP-MS. Calorimetric measurements of tested mixtures fresh pastes were implemented to learn about setting process. Hardened binder specimens were tested for bending and compressive strength.
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The influence of barium oxide on the formation and properties of portland clinker
Zezulová, Anežka ; Šoukal, František (referee) ; Opravil, Tomáš (advisor)
Portland clinker is thanks to its large-scale production a continuously studied topic. Clinker, or Portland cement, is used for construction purposes, or for insulation and special applications. One of these special applications could be shielding of different types of radiation by making use of the content of barium ions. The present master’s thesis examines the influence of barium oxide on the formation and properties of Portland clinker, which could be, by incorporation of barium ions into the system, used as a binder for buildings resistant to various types of radiation. Barium sulfate and barium carbonate were added to the raw meal in order to prepare clinkers with different content of barium oxide. The effect of barium on the formation of clinker phases was studied (by XRD – Rietveld analysis and by the microscopic point integration), as well as the effects on the variations of temperature of the phase formation (TG-DTA) and the rate of alite formation under isothermal conditions. Furthermore, the ability of barium to become a part of clinker minerals was studied by SEM with EDS, and the solubility of barium phases by ICP-OES. The hydration of clinker minerals containing barium was studied by isothermal calorimetry.
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The possibilities of use of sludges from limestone wash
Švec, Jiří ; Šoukal, František (referee) ; Opravil, Tomáš (advisor)
In modern point of view of waste management is desirable to effectively process the grates possible amount of wastes. Sediments from cleaning of mined lime stones contains a lot of clay components, but there is also indispensable share of soft calcite. This composition makes these sediments a promising material for preparation of hydraulic binders. Production of common hydraulic binders, especially Portland cement, is very energy-intensive plus loads environment with considerable amount of combustion gases, therefore it is necessary to explore possibilities of alternative low - energy binders production and usage.
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The study of degasing process during thermal treatment of advanced ceramic
Kocián, Karel ; Šoukal, František (referee) ; Ptáček, Petr (advisor)
This bachelor thesis deals with mechanism and kinetics of the burnout of additives during thermal treatment of ferrite ceramics. In order to establish this process thermal analysis were used, specifically: simultaneous thermogravimetric determination, differential thermal analysis and thermal analysis with evolved gas analysis (TG-DTA and EGA), high-temperature microscopy (HM), burning test in kiln with controlled atmosphere and high-temperature X-ray diffraction (HT-XRD). To determine the elemental composition after sintering and characterization of the sample, scanning electron microscopy (SEM) was used.
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Polymer-cement composites for refractory aplications
Zbončák, Marek ; Ptáček, Petr (referee) ; Šoukal, František (advisor)
This bachelor thesis deals with preparation of high-strength polymer-cement composites based on the calcium aluminate cement and polyvinylalcohol. MDF composites are interesting because of their mechanical properties which exceed strengths of the common materials based on the cement and inorganic binders. So they represent perspective kind of material which could be used for construction purposes. Thermal degradation of the polymer leads to structure changes of the composite and reduction of mechanical properties. Therefore thesis is aimed to characterize the influence of the temperature on mechanical properties, structural changes and material composition. Temperature dependence of flexural strength was examined during the work. Changes of composition and structure were characterized by XRD, DTA-TGA in combination with EGA, SEM and EDS analyses. Due to requirement of the material refractoriness there were also tested options of preparation of MDF composites based on phosphates binders which are used in refractory manufacture.
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Increasing the whiteness of kaoline
Bartošík, Jan ; Ptáček, Petr (referee) ; Šoukal, František (advisor)
The thesis deals with the issue of increasing the whiteness index of kaolin raw material. The research was focused on floating the kaolin suspension and the subsequent processes related to increasing the whiteness index. Increasing the whiteness of the kaolin raw material took place on the basis of acid leaching. The eluents were based on sulfuric acid, phosphoric acid, oxalic acid and sodium bisulfite. The leaching process was influenced by the temperature and concentration of the leaching agent. Floated and leached kaolin samples were characterized by several methods. The XRD method investigated the mineralogical composition and the kaolinite structure order. The distribution of chromogenic components was monitored by SEM-EDS. Residues of organic matter was determined by COD test and the concentration of chromogenic components in the extract was monitored by the ICP-OES method. Last but not least, the index of whiteness was measured, the increase of which is the aim of the diploma thesis, using a UV-VIS spectrometer with reflective extension.
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