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Development of chemically resistant sprayed mixture
Hermann, Radek ; Dohnálek,, Pavel (referee) ; Drochytka, Rostislav (advisor)
Production wastes for which a direct use in another production is found become secondary raw materials. There are several institutions in Czech Republic and in the world, which are currently dealing with the issue. This thesis deals with the issue of cementitious spray concrete mixtures and deals with the possibilities of using secondary raw materials and waste from production as partial replacement of binder and filler in these mixtures. The aim of this theses is to optimize the composition of additives in the recipe of the commercially produced pray mixture and to verify the influence of the degree of substitution of binder or filler by secondary raw materials on its physical-mechanical properties. The aim is to maintain or increase these properties while substituting the binder and filler as much as possible. After the evaluation of results, it is possible to say, by suitable optimization of the additives it is possible to achieve a significant improvement of the physical-mechanical properties of the mass and furthermore, from the results of this thesis follows, that by substitution of 100% fine filler in combination with substitution of 30% binder it is possible to maintain or increase the physical-mechanical properties after 28 days of curing and to significantly increase these properties after 90 days of curing. The results of this thesis are also related to the reduction of economic impact on production of the spray mixture, mainly due to the use of secondary raw materials.
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Composite materials with silica matrix in the environment of high temperatures
Lisztwanová, Ewa ; Luňáček,, Martin (referee) ; Bydžovský, Jiří (advisor)
This thesis deals with the study and design of composite materials based on silica matrix suitable for extreme conditions, eg. for the repair of concrete structures with anticipated increased risk of fire. The theoretical part summarizes basic knowledge concerning the fire resistance of structures and the behavior of the composite system during extreme conditions. Theoretically oriented section also contains information on alkali-activated materials and their use in high temperature environments. Based on the evaluation of the theoretical part of the experiment were designed and tested different types of composite materials with increased content of raw materials from alternative sources. Laboratory research has been based on testing of basic physico-mechanical parameters including phase composition and microstructure of the proposed formulations before and after thermal exposure of 1200 ° C. Also considered was the effect of different cooling conditions.
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The effect of particles size on the properties of mortars.
Sehnal, Tomáš ; Krátký, Josef (referee) ; Šiler, Pavel (advisor)
The consumption of concrete as a building material is still increasing over the world. Concrete production is closely associated with CO2 and other greenhouse gases emissions. The reduction of these emissions can be achieved by a higher utilization of secondary raw materials in cement mixtures. This bachelor work is focused on the using of secondary raw material, finely ground granulated blast furnace slag and fly ash from fluidized bed combustion and high temperature combustion. The properties of milling pure cement and cement mortars with addition of secondary raw material will be measured. Compressive strength, flexural strength, and calorimetric measurement will be performed for these prepared mortars.
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Economic aspects of environmental use of building materials based on secondary raw materials.
Ťažký, Tomáš ; Durica,, Tibor (referee) ; Sedlmajer, Martin (referee) ; Nosek,, Karel (referee) ; Kulísek, Karel (advisor)
The disses thesis is focused on usage of secondary raw materials from the electric power industry, specifically fly ash as a component for the building industry, concentrated on concrete. Two main streams are covered, environmental and economical. Reasons, which led to focus on the selected subject are coming mainly from the scarcity and availability of high-quality mineral resources, environmental pressure for usage of industry byproduct, reducing emissions and economical pressure to reduce production cost, especially raw materials. The main purpose of the work was to verify the possibility of increasing the usability of fly ash as a mineral additive in the technology of concrete production with materials retrieved from coal fired power plants and applying mechanical activation of fly ash. The main goal of the experimental part of work was to demonstrate improvement of fresh and hardened concrete properties as a main condition to support economic efficiency of mechanical activated fly ash. Base on previous facts the methodology was covering two main areas, the experimental and the assessment. Relatively large sets of tests were performed, using a wide range of tested high temperature fly ash and fluidized bed combustion fly ash granulometrically treated, by mixing and grinding. Results of the testing confirmed focused parameters for concrete and mortar mechanical properties, total economical efficiency of the targeted solution and the subject of the dissertation. In the experiment section has been retrieved valuable findings contributing to the overall knowledge of the faculty, also for the practical application. The results of the tests confirmed the achievement of the planned target parameters, both in terms of physical and mechanical properties of experienced mortars and concretes, as well as the overall economic efficiency of the proposed design and the topic of the disses thesis. Within the experimental work, valuable professional knowledge and benefits w
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Study of microstructure of autoclaved aerated concrete with using of secondary raw materials
Martanová, Jana ; Suchý, Peter (referee) ; Kulísek, Karel (advisor)
Autoclaved aerated concrete is a used building material, especially for its thermal insulating properties. During autoclaving, an aerated concrete microstructure produces crystalline CSH phases, primarily tobermorite. The ingoing substances are calcium oxide and silica. In addition to commonly used raw materials, secondary raw materials rich in silicon dioxide can be used for production. The use of secondary raw materials gives the opportunity for the construction industry to be more environmentally friendly. Another benefit is the reduction of financial costs. The work explores the influence of individual secondary raw materials on the microstructure. High-temperature fly ash, fluid fly ash, cinder, ground glass and zeolite were used The raw materials were mixed with unalloyed lime at a molar ratio of calcium oxide to silicon dioxide of 0.73 and 1.0. Autoclaving capsules were used to synthesize tobermorite under laboratory conditions. Autoclave was performed at 170 °C and 190 °C with hydrothermal durations of 4, 8 and 16 hours. The most important influence on the microstructure was high-temperature fly ash, on the contrary, the greatest influence on the mechanical properties is attributed to the ground glass.
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Influence of Zinc in Byproducts on Hydration and Properties of Blended Portlands Cements
Šilerová, Iva ; Palou, Martin (referee) ; Rovnaníková, Pavla (referee) ; Havlica, Jaromír (advisor)
The theme of this work is to monitor the effect of zinc on the properties of blended Portland cements. Zinc was tested in the form of two-soluble salts: Zn(NO3)22 H2O and ZnCl2 and a very slightly soluble compound ZnO. Blended cements were prepared by partial replacement with finely ground granulated blast furnace slag, high-temperature and fluidized bed combustion filter fly ash. Flow properties were studied on the prepared pastes. Impact on hydration reactions was examined by using of isothermal and isoperibolic calorimetry. Flexural and compressive strength were measured as mechanical properties of the prepared test specimens. The phase composition of the prepared composites and incorporation of zinc ions in the cement matrix via leaching tests and FTIR analyzes were also studied. Microstructure development of cement samples was tested by SEM analysis with EDS. Influence on ecotoxicity was also measured.
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Optimisation of cement-bonded particleboard matrix composition by using alternative raw material sources
Roháček, Lukáš ; Vacula, Miroslav (referee) ; Bydžovský, Jiří (advisor)
The diploma thesis deals with possibility of utilization raw materials from alternative sources for production of cement-bonded particleboards. In theoretical part the possibilities of modifying composition of cement-bonded slabs with emphasis on their matrix are discussed in detail. On basis of the findings and their evaluation, waste from the formatting of cement-bonded particleboards, micronized limestone, heat sink and high temperature fly ash were selected to the composition modification. The mentioned raw materials were analyzed and subsequently tested as substitutes for the matrix of cement-bonded particleboards in the experimental part. The properties of the proposed materials were tested even in the longer term, including the microstructure.
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Specific cement composite based on secondary raw materials with emphasis on durability
Figala, Petr ; Dohnálek,, Pavel (referee) ; Drochytka, Rostislav (advisor)
Nowadays the attention to the utilization of secondary raw materials as a component of building materials is being paid to in the Czech Republic and in the world. This thesis deals with possibilities of using secondary raw materials as partial cement substitutes in industrial floors. The aim of this thesis is to verify the influence of cement substitution amount with secondary raw materials and their fineness of grinding on the properties of the floor surface in time and on its structure. On the basis of the acquired knowledge, the influence of the pre-treatment of the secondary raw material on the properties of the floor ceiling with an emphasis on the economic aspect was assessed. After evaluating the results, some substitution of cement in the floor screed with secondary raw materials is beneficial. The significant influence of more intensive milling of the floor screeds base on the parameters of the final floor screed was not confirmed. It seems, that it is possible to achieve very good results even when using secondary raw materials with a lower percentage of fine particles. This brings together the economic benefits of lowering the cost of a lower dose of expensive cement by using cheaper secondary raw materials, because pre-treatment of such materials does not require the use of a large amount of energy.
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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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