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Development of new grouting materials for reverse grouting of sewers
Dolák, Martin ; Dohnálek,, Pavel (referee) ; Drochytka, Rostislav (advisor)
ABSTRACT This thesis deals with the development of silicate based reverse grouts for the purpose of rehabilitation of sewers. The work also examines the possibility of substitution of basic input raw materials with secondary raw materials, meaning replacements of both filler components and binder components. As secondary raw materials, we refer to wastes from the production process which, after the necessary treatment, are used in another production. The development and experimental verification of the functionality of the developed grout was focused mainly on the use of secondary raw materials as much as possible, while maintaining or even improving its physical and mechanical properties. Based on the results of the work, it can be stated that with a 100% replacement rate of filler components in combination with 20% replacement rate of binder components, it is possible to largely maintain the properties of the material, or even optimize them. The results of the thesis also point to the possibility of reducing the economic and environmental demands of production of building materials.
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Studying the properties of fiber cement composites
Cederová, Kristýna ; Hoško, Marek (referee) ; Bodnárová, Lenka (advisor)
This diploma thesis deals with fiber-cement composites. Input materials are investigated for the production of fiber cement, are examined, the production and parameters of the pulp were monitored. Further, Hatschek's production technology and requirements for corrugated fiber-cement roofing are described. In the practical part the individual input materials and parameters of ground pulp were verified. The problem with production of samples and difference in the fineness of pulp milling in fiber cement products has been solved.
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Cement worm conveyor
Šulc, David ; Malášek, Jiří (referee) ; Škopán, Miroslav (advisor)
This bachelor´s thesis contains of a detail and design of a sloping cement worm conveyor, based on specified parameters. This work deals with the calculation of the main conveyor parts, design size and strength of the control sections. Then there is also a solution method of storing a worm shaft. The thesis is composed of technical reports and drawings, which includes general assembly drawings, assembly drawing of the screw, and a list of items.
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The usability of secondary raw materials in the design of liquefied suspensions based on soil
Hrubý, Jakub ; Kulísek, Karel (referee) ; Černý, Vít (advisor)
The bachelor's thesis deals with the usability of secondary raw materials in the design of liquefied suspensions based on soils in the form of self-compacting grouts. The soil treated in this way can be used as a substitute for backfill material for excavations of engineering networks. The theoretical part deals with the classification and description of soils. Furthermore, the types of soil stabilization using lime, cement, including their liquefaction, are mentioned. A wide range of potentially suitable secondary raw materials and liquefaction mechanization is presented. In the practical part, the basic soil F6-Cl is selected on the basis of a set of available soils. The basic reference mixture consists of soil, lime, cement and liquefier. A proposal for the concept of experimental verification is presented. Part of the concept is the automated calculation of input raw materials. The effect of the action of the superabsorbent polymer and the accelerating additive is verified. Based on optimization selections, functional secondary raw materials are selected. The basic recipe with the optimal amount of accelerating ingredient achieves the best results. Recycled concrete and brick generally improve the resulting parameters. Bed ash achieves the highest strength with the lowest shrinkage.
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Effect of colloidal silicon dioxide on selected properties of cement pastes and mortars
Barek, Jaroslav ; Žižková, Nikol (referee) ; Rovnaníková, Pavla (advisor)
The presented diploma thesis deals with the potential use of colloidal silica in cement composites. Investigation is focused primarily on selected properties of cement pastes and mortars with colloidal silica content. Two selected types of colloidal silica (particles with average size of 14 nm) have been used as a cement addition and partial replacement of cement, respectively. The experimental program for cement pastes with colloidal silica included tests for isothermal calorimetry (the study of cement hydration) and thermal analysis (determining the portlandite content). Hardened cement pastes have been studied through measurements of compressive strength. The microstructure was examined by scanning electron microscopy. Hardened mortars with colloidal silica have been studied through measurements of compressive strength, flexural strength, modulus of elasticity and fracture mechanics parameters. Fracture mechanics tests show that 5 % and 20 % addition of colloidal silica can enhance after 28 days of curing fracture energy up to 18,4 % and 32,7 %, respectively. For the compressive strength enhancing effect of colloidal silica, it was found to be more pronounced in the early age, while rate of strength gain can be lower than the control in the later ages. Our investigations revealed that the silica sol will coagulate immediately when the cement is mixed into the water containing sol. The ionic composition of pore fluid significantly influences the stability of colloidal silica and lead to their aggregation. After additional tests it has been found that small addition of calcium hydroxide greatly improved the compressive strength of the resulting cement pastes with colloidal silica content. Addition of calcium hydroxide in conjunction with modified cement paste preparation can enhance compressive strength after 3 days of curing up to 64,4 % in comparison with the blank paste.
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Flow Measurement of Hot Dusty Gas
Dostál, Jiří ; Štohl, Radek (referee) ; Šedivá, Soňa (advisor)
The bachelor thesis deals with the measurement of hot dusty gas. The introduction outlines the problems of measurement. Another part of the work contains a theoretical introduction to the measurement of gas flow. In successive chapters the basic principles and characteristics of suitable methods for measuring the hot dusty gases are described. Finally, the function blocks are implemented in the Simatic STEP7 for calculation of volume flow rate for the methods selected in the theoretical part and visualization in WinCC flexible.
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Effect of active ingredients to the activity of cementing compound with non-alkaline accelerator additive for sprayed concrete.
Závacký, Jakub ; Hela,, Vlastimil (referee) ; Hela, Rudolf (advisor)
The bachelor thesis deals with the problems of the sprayed concrete with the focus on usage of the active ingredients with non-alkaline accelerator additive. The theoretical part covers the current level of knowledge of how the active ingredients are used in the sprayed concrete and their influence on the process of hydration. In the experimental part the reactivity of cementing compound with non-alkaline accelerator on the basis of aluminium sulphate were compared in a laboratory when the active ingredients (such as slag, fly-ash and very fine limestone) were used. The cements CEM I 42,5 R, made by different producers were verified on the basis of the setting time and early strength gain using the Vicat needle to examine the mechanical properties after 6 and 24 hours.
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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.
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Use of alternative binders in bound mixtures from waste building materials
Jakub, Tomáš ; Hýzl, Petr (referee) ; Stehlík, Dušan (advisor)
This diploma thesis is focused to use bonded base layers with different types of admixures for base layers of roads. The first, theoretical part of the work deals with summary of the available literature. Deals with basic and uncoventional type of admixures used for bonded base layers. The second, partical part of the work deals with comparsion of 5 bonded base layers with recycled asphalt with added artifical fibers, cellulose fibers or without admixures and one mixtures created only from First of all is described tesťs methods with design of mixtures and described materials. In the practical part of the work was tested compressive strength, transverse tensile strength and compressive strength after effects of frost. In the end of the work is comparsion all mixtures between themselves and determination effects admixtures on compressive strength and transverse tensile strength.
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