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The development of composites based on inorganic binders designed for the extreme applications
Janoušek, Petr ; Šácha, Libor (referee) ; Dufka, Amos (advisor)
The topic of this master's thesis is the development of composite materials based on inorganic binders for use in extreme conditions. It means especially geopolymeric or alkali activated materials (AAM) based composites. The theoretical part of this thesis summarizes knowledges about the development and use of alkali-activated materials, their structure and mechanisms of their formation. It also deals with the applicable raw materials for AAM and their exciters, which are in particular water glass and sodium hydroxide. There also have been a summary of the effects of high temperatures and chemicals on the mechanical properties of AAM and the requirements of standard EN 1504-3 for repairing materials. The task of the practical part was to develop a repair mortar for concrete structures based on AAM so that its production was as simple as possible, ie one-component materials. Gradually six recipes have been develeoped. Test specimens made from these recipes have been putted to selected tests according to the requirements of ČSN EN 1504-3.
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Comparison of environmental and technological properties of various methods of manufacture of foundry moulds and cores
Dlouhá, Monika ; Rusín, Karel (referee) ; Cupák, Petr (advisor)
The roots of foundry manufacture perhaps go back to 2000 BC. Since foundry production in its development has undergone four stages and each of them there was a qualitative jump. From 20 century, the chemicals used in foundry moulds and cores which is the cause producing harmful substances that have a negative impact on the environment. Major sources of harmful substances are just binders, hardeners and catalysts that are needed for bonding of moulding mixture. The third stage deals with the foundry physical processes that are not using today, even though they are most ecological. Nowadays the most used methods Cold-box, Warm-box and Hot-box.
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Study of synthetic sandstones preparation possibilities
Solik, Jaroslav ; Kalina, Lukáš (referee) ; Opravil, Tomáš (advisor)
This thesis explores the possibility of developing synthetic sandstones based on alkaline-activated (geopolymer) binders. The goal is to design an appropriate connective system of optimal concentration, so that the prepared material (artificial stone) showed similar characteristics as natural. The experimental section summarizes the experiments that explore several different alkali connective systems. The aim is to compare the properties of binders prepared from methakaolin (Mefisto K-05 and L-05) alkali-activated by sodium or potassium water glass. For comparison with these connective systems were also prepared samples of commercially supplied geopolymer binder called Baucis
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Modern anorganic foundry binder systems
Kolařík, Martin ; Rusín, Karel (referee) ; Cupák, Petr (advisor)
This bachelor thesis deals with newly developed inorganic binder systems. These are mainly developed for their ecological advantages. However, some of the discussed binder systems have better technological properties. Inorganic binder systems are described herein, both on the basis of alkaline silicates and on the basis of inorganic salts. Attention is also paid to bentonite, which is still the most commonly used binder in the world. It turns out that these binder systems will be important for the future of the foundry industry.
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Possibilities of the utilization of the waste sand from the water glass production in building industry
Bílek, Vlastimil ; Kalina, Lukáš (referee) ; Opravil, Tomáš (advisor)
Nowadays, the waste sands from the water glass production have no utilization and due to high alkali content are considered as a dangerous waste. So the aim of this thesis is to find and study some possibilities of their utilization in the building industry. First of all, some necessary analysis of these sands were performed and then some advantages and disadvantages of their application for production of materials based on portland cement and alkali activated materials were studied. Characteristics of fresh and hardened pastes, mortars and concretes containing these waste sands were determined. The most tested properties were their workability and their compressive and flexural strength. Close attention for the risks of alkali-silica reaction and for options of its suppressing by the mineral admixtures was paid.
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The development of composites based on alkali-activated matrices resistant to extreme temperatures
Ševčík, Marek ; Šácha, Libor (referee) ; Dufka, Amos (advisor)
The diploma thesis is focused on the development of composites from alkali activated materials (AAM) and their resistance to extreme temperatures. The theoretical part describes alkaline activation and precursors for the production of AAM. Furthermore, the problem of the effect of extreme temperatures on these materials is described. In the experimental part, the optimal silicate modulus with respect to the properties of AAM was gradually determined, and the effect of extreme temperatures on the AAM matrix was verified. In the next stage, the effect of the filler with respect to the behavior at extreme temperatures was tested and then the final formulation was optimized.
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Methodology for determining the chemical composition of water glasses
Flídrová, Michaela ; Bartoníčková, Eva (referee) ; Kalina, Lukáš (advisor)
The bachelor thesis deals with the methodology of determination of the chemical composition of water glasses. The aim was to find a more suitable method than the colorimetric analysis used by one of the domestic water glass manufacturers. The current procedure can be used to determine the content of Me2O (Na2O, K2O, Li2O), however, in the determination of SiO2 the method is inaccurate since the color change of the indicator during the second titration is very slow and therefore the equivalence point is ambiguous. The main aim of this work was to find a suitable method for the complex determination of the chemical composition of water glasses, which is compared with other methods used in the analytical chemistry of silicate materials. A very promising method is the conductometric titration with a volumetric hydrochloric acid solution, which provides an accurate, fast and instrumentally inexpensive method of chemical determination.
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Modern anorganic foundry binder systems
Kolařík, Martin ; Rusín, Karel (referee) ; Cupák, Petr (advisor)
This bachelor thesis deals with newly developed inorganic binder systems. These are mainly developed for their ecological advantages. However, some of the discussed binder systems have better technological properties. Inorganic binder systems are described herein, both on the basis of alkaline silicates and on the basis of inorganic salts. Attention is also paid to bentonite, which is still the most commonly used binder in the world. It turns out that these binder systems will be important for the future of the foundry industry.
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Thermoproperties of foundry moulds in dependence on different used foundry sands
Šuráň, Jiří ; Rusín, Karel (referee) ; Cupák, Petr (advisor)
The project elaborated in frame of engineering studies is submitting the study of thermal properties of holding mixtures using different types of sand. Were tested a total of 5 sands: zirkon, ŠH22, chromite, olivine and dunite. Molding compounds were tested for thermal capacity, thermal conductivity and heat accumulation. The highest heat capacity was achieved in dunite sand. The largest heat accumulation had mixture with chromite sand and the best thermal conductivity was found in a mixture with olivine sand.
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Water Treatment Plants Innovation Opportunities
Zelený, Zdeněk ; Biela, Renata (referee) ; Kučera, Tomáš (advisor)
This master´s thesis deals with the possibilities of innovation process water treatment. Specifically, to explore the use of sodium water glass and nanoiron in removing heavy metals from raw water at the drinking water treatment. For the comparison was used traditionally used coagulant, particularly liquid aluminum sulfate. The introductory part deals with the possibility of modifying the surface water during the treatment process such water into potable water. This chapter is a description of the quality of raw water used, then the description of currently used separation processes. Furthermore, they are described and commonly used types of treatment plants. Conclusion The introductory section deals with traditional coagulants and form a suspension. Another part of this master´s thesis has been devoted to the possibilities of innovation in the treatment of raw waters as drinking water, describes the options and features of the use of water glass and nanoiron. The following section describes the experimental part of this thesis. It is followed by the experimental results. The last chapter summarizes the acquired knowledge and commented on the measured values of the experimental part. This work also shows several specific projects using innovative technologies presented.
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