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Effect of curing conditions on the properties of alkali activated slag
Rypák, Peter ; Bayer, Patrik (referee) ; Rovnaník, Pavel (advisor)
Combination of fine ground granulated slag with proper alkaline activator gives alkali-activated slag – a material with remarkable properties. Theoretical part of the thesis deals with summarizing basic informations about alkali-activated slag, its properties, production and utilization. It also follows research devoted to effects of curing of alkali activated slag and shrinkage-reducing admixtures on its properties. Objective of the experimental part is to determine the influence of curing conditions on the mechanical properties and microstructure of alkali-activated slag. These properties are also monitored in alkali-activated slag with carbon nanotubes and hydroxypropylmethylcellulose as an shrinkage-reducing admixtures.
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The issue of concrete resistance to high temperatures
Krejčík, Jakub ; Hela, Rudolf (referee) ; Bodnárová, Lenka (advisor)
Bachelor´s thesis deals with resistance of cement concrete to high temperatures. Theoretical part of bachelor´s thesis describes changes that occures in concrete at thermal loading and behavior of each component of concrete. Next there were discribed ways to improve resistance of concrete to high temperatures, by choosing the right component or by adding fibre reinforcement. In experimental part composites with bassalt and polypropylen fibre and with bassalt aggregates were tested. In these composites changes of compressive strenght and changes of density were mesured according to the thermal loading. Next individual fibre reinforcement polypropylen, celulose and bassalt fibres were exposed to the thermal loading and their changes were observed.
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The issue of the use of carbon nanotubes in cement composites
Pacltová, Klára ; Hela, Rudolf (referee) ; Bodnárová, Lenka (advisor)
The bachelor thesis deals with the analysis of the efficiency of carbon nanoparticles in cement composites. The theoretical part of the bachelor thesis is focused on the research of information about carbon nanotubes and their influence on cement composites. The practical part follows the research of the theoretical part, where is verified the effectiveness of carbon nanotubes in cement composites at different dosages.
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Effect of flexural loading on electrical properties of alkali-activated slag composites
Šimko, Lukáš ; Kusák, Ivo (referee) ; Rovnaník, Pavel (advisor)
Ordinary concrete is the most commonly used building material, but nowadays the requirements for low energy consumption, durability of structures together with their easy diagnostics as well as ecological production raises. This thesis deals with cement and aluminosilicate composites with content of conductive fillers, which allows to monitor the change in electrical properties, most commonly electrical resistance in dependence on mechanical stress. In the experimental part of the thesis, test beams were produced based on alkali-activated slag with content of carbon nanotubes, graphite powder, carbon black and carbon fibre. The beams were subjected to flexural loading in a three-point bending configuration and the shift in electrical resistance was monitored.
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Carbon nanotubes in building materials
Fialová, Barbora ; Bayer, Patrik (referee) ; Rovnaník, Pavel (advisor)
Carbon nanotubes (CNTs) has become of great interest for scientists in many disciplines. This study examines the effect of CNTs as nanosized reinforcement for metakaolin–based geopolymer. It was found out that the addition of CNTs considerably affects the compressive and flexural strength geopolymer samples. The influence of CNTs on microstructure was examined using mercury intusion porosimetry and scanning electron microscopy.
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Verification of properties of concretes with nanoparticles
Pacltová, Klára ; Hela, Rudolf (referee) ; Bodnárová, Lenka (advisor)
This diploma thesis deals with the influence of addition of carbon nanoparticles on cement composites. The theoretical part of the diploma thesis is focused on the research of information about carbon nanoparticles, more precisely about carbon nanotubes and graphene oxide. There are summarized methods of dispersing carbon nanotubes and their effects on cement composites. The practical part follows the theoretical part of the research. In the first phase, the correct technique of graphene oxide dispersion was verified. Subsequently, the effects of graphene oxide on the mechanical properties of cement mortars were verified. In the final phase of the diploma thesis, the knowledge gained from the previous part was verified on concrete samples.
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The use of micro and nanotechnology to develop ultra high strength and high performance concrete with special features
Vlč, Viktor ; Ťažký, Tomáš (referee) ; Hela, Rudolf (advisor)
The use of nanotechnology has become wide spread in all branches of science. Nanotechnology help us to understand microstructure and due to the world has started to produce new materials. One of many examples carbon nanotubes (CNTs). In diploma thesis I tried to find the way of successful introduction into concrete mixture. I was studying influence of CNTs and other nano particles and I was comparing them with referential samples (without CNTs). Also I tested the improvement of mechanical characteristics of concrete. The morphology of nano particles was studied using Scanning Electron Microscopy (SEM). The results show that introduction of nanoparticles to results in increasing strength and higher density. That is why High Performace Concrete so resistant and durable.
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Study of catalytic activity of ceramic perovskite materials for energy applications
Schlosser, Radek ; Cihlář, Jaroslav (referee) ; Cihlář, Jaroslav (advisor)
In this diploma thesis the preparation of ceramic catalytic materials was studied. They were studied by means of catalytic activity on powder samples and in a form of membrane as well. At first were multicomponent perovskite materials with the help of “glycine-nitride synthesis” synthesized. Two types of perovskite systems were prepared. First system was on the basis of nickelates LaNiO3 and the second one on the basis of cobaltites SmCoO3. Both of them were doped with aluminium and calcium. Ceramic powders were catalytic tested during reformed reaction. A part of powders was pressed with hydraulic biaxial press. Then the membranes were calcinated, sintered and polished. The membranes were tested to specify the catalytic activity. At first they were in hydrogen atmosphere reduced and afterwards came through the partial oxidation. The appearance of coke fibers on the surface was discussed.
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Study of concrete properties with nanoparticles
Michnová, Kamila ; Hela, Rudolf (referee) ; Bodnárová, Lenka (advisor)
This diploma thesis discusses the basics of nanotechnology as a science and nanotechnology of concrete. Additionally, it describes carbon nanotubes and the possibilities of their dispersion using high shear mixing and sonication. This thesis further provides findings about ultrasonic dispersion parameters and characteristics of materials with the addition of carbon nanotubes. The experimental of part of this thesis focuses on the possibility of dispersing carbon nanotubes, deals with the issue of incorporating carbon nanotubes into the concrete matrix and describes its effects on the final properties of concrete. It has been observed to which extent the carbon nanotubes may affect selected physico-mechanical properties and durability of concrete.
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