National Repository of Grey Literature 98 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Desin of new technologies for invert grouting of masonry sewer
Dolák, Martin ; Melichar, Tomáš (referee) ; Drochytka, Rostislav (advisor)
The subject of this work is to find optimal grouting mixture for repairing existing brick sewer with insistence on ecological modesty. Secondary raw and waste materials will be evaluated as a partial replacement of good-quality materials, that are commonly used. Production wastes for which is after necessary adjustment found usage in another sphere of production are named secondary raw materials. In the end will be made a selection of appropriate secondary raw materials for a project of new technology of back grouting identified for repairing currently used brick sewers.
Methods of using cement kiln by-pass dust in building materials technology
Sikorová, Věra ; Koplík, Jan (referee) ; Kalina, Lukáš (advisor)
This diploma thesis is focused on methods of using cement kiln by-pass dust in building materials technology. By-pass dust was treated to remove chlorides and could then be used as other constituent to various types of cements in the amount of 0–5 wt. % according to ČSN EN 197-1. The properties of dusts before and after chloride removal were examined and after incorporating modified by-pass dust into the cement, the properties of fresh and hardened cement pastes and mortars were studied. It was found that modified by-pass dust after incorporation into cement fulfill requirements of ČSN EN 197-1.
Preparation of modified tricalcium aluminate phases and study of their hydratation processes
Vávrová, Alžběta ; Koplík, Jan (referee) ; Másilko, Jiří (advisor)
This diploma thesis deals with the preparation of modified tricalcium aluminate phases using sodium ions, and the study of their hydration processes and products. The X-ray diffraction analysis, isothermal calorimetry, laser diffraction, and scanning electron microscopy with energy dispersion analysis were used to solve this task. The preparation of modified tricalcium aluminate phases using high temperature methods has been described in the experimental section. Furthermore, the X-ray diffraction analysis was used to determine the purity of the prepared phases and the scanning electron microscopy with energy dispersion analysis was used to define the volume of sodium. Laser diffraction was used to measure a particle size distribution in the individual phases. Subsequently, hydration of the pure phases was performed in an isothermal calorimeter. It was followed by hydration of phases in the presence of different gypsum content and then in the presence of saturated portlandite solution. Hydration of some samples was stopped in order to better understand the hydration process. Hydration products were studied by X-ray diffraction analysis. The obtained results were compared with each other and the influence of sodium ions on both the structure of the prepared phases and the course of hydration and its products has been discussed. The effect of adding different volumes of gypsum and portlandite on the course of hydration of the individual phases was also compared.
Research of soil reuse technology in the form of self-compacting grouts
Michalčíková, Magdaléna ; Kolář,, Karel (referee) ; Turček,, Peter (referee) ; Sokolář, Radomír (referee) ; Drochytka, Rostislav (advisor)
The increasing volume of waste of all kinds is currently a phenomenon of economically developed society and one of the problems of environmental protection. It is therefore imperative, in the interest of sustainable development, to monitor impacts related to the impact on our ecology, to regulate waste production by legislation and universally promote their reuse and recycling. Construction and demolition waste occupy a significant share of the total waste volume. This category also includes excavated soils. Recycling of these materials could significantly reduce the amount of landfilled waste and at the same time, these materials could be used as an important source of secondary raw materials. The doctoral thesis describes the research and development of the new technology of reuse soils in the form of self-compacting grouts. The result of the solution will be a suspension of optimal rheological properties, providing a perfect leaking around the stored utility networks. Emphasis will be placed on the study of the interaction of different types of soils with the stabilizers, flowable or plasticizing additives and its typical dispersible substance, including verification of the developed technology in situ.
Spiral conveyor
Sklenář, Jiří ; Pokorný, Přemysl (referee) ; Malášek, Jiří (advisor)
The content of this work is the theoretical description of the screw conveyors and the design of the structural solution of the spiral screw conveyor based on the specified parameters. Part of this work is drawing documentation based on basic calculated parameters.
The development of high-strength concrete with a high content of el. fly ash
Roubal, David ; Ťažký, Tomáš (referee) ; Hela, Rudolf (advisor)
This diploma thesis deals with the study of high-strength, high-volume fly ash concrete. The theoretical part of this thesis focuses on the detailed characteristic and main principles of high-strength concrete, high-volume fly ash concrete. In addition, according to the findings, the technology of high-strength and high-volume fly ash concrete, including principles of high strength, has been described. On the basis of the findings, high-strength, high-volume fly ash concrete for specific compressive strengths has been designed and created in the experimental section. These concretes were then subjected to a number of tests.
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.
Influence of variations in cement composition on bleeding and mortar workability over time
Peřina, Tomáš ; Klečka,, Tomáš (referee) ; Hela, Rudolf (advisor)
This diploma thesis is divided into two parts, the theoretical and practical part. The theoretical part is to study of factors influencing the workability and bleeding of concrete. There is mentioned the production of cement and standard requirement. The task of the practical part is to assess the cements produced by the cement works Hranice and Prachovice. These cements test in terms of water separation. In combination with these cements use superplasticizing admixtures from Mapei and Stachema and determine the impact of water separation on cement pastes. Determine rheology on the cement pastes. Define influence of variations in cement composition affect the stability of cement mixtures.
Effect of the currently used plasticizers for concrete hydration temperature
Knotová, Kateřina ; Halas, Vladimír (referee) ; Sedlmajer, Martin (advisor)
Plasticizing and superplasticizing admixtures are the key components of nearly every concrete. These admixtures improve workability of mortar and fresh concrete which lead to facilitation of depositing and compaction. Adding of plasticizers or superplasticizers enables to change properties of fresh and hardened concrete, especially to reduce water-cement ratio, thereby increasing strength and durability of concrete or to improve other properties. The main aim of this thesis is to monitor the effect of plasticizing admixtures and their dosage on the rheology and hydration of concrete with emphasis on the development of hydration temperature. The other goal is to examine their strength qualities. Behaviour of plasticizing admixtures is analysed at first on cement pastes, as simple systems, and then verified on concrete.
The use of the secondary aggregates to pavement
Hurtiš, Maroš ; Hrbek, Kamil (referee) ; Stehlík, Dušan (advisor)
The master thesis deals with the possibilities of using waste aggregate from main rock production to hydraulically bound mixtures, witch are used in base and sub base pavement. The theoretical part describes conditions and properties of bound mixtures, aggregates and cement. The practical part describes the process of design, mixture preparing and laboratory test carried out on them. The bound mixtures are testing in compressive strength, frost and water resistace and resilient modulus.

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