|
|
Thin-layer mortar mixtures
Ďurtová, Aneta ; Gazdič, Dominik (referee) ; Fridrichová, Marcela (advisor)
The bachelor thesis focuses on the development and properties of singlelayer or thin-layer reliefs formed by the partial substitution of binder components of waste materials, Portland cement and lime hydrate. For the proposed mixtures that have been prepared in the laboratory, they have been verified by the standard of prescribed properties.
|
|
|
Mixing cement for special purposes
Hrdina, Matěj ; Kulísek, Karel (referee) ; Fridrichová, Marcela (advisor)
Thesis deals with the technology of production of portland cement its raw material composition, mineralogical composition, theory of clinker minerals during firing and possible mixing with other materials suitable character. It provides an overview of specialty cements. It was prepare a proposal cement mixtures normatively called "Masonry cement." Cement was examined on required properties depending on the amount and the type of chemical additives.
|
|
|
Possibilities of utilization of solid residues from fluidized bed combustion for preparation of composite Portland cements
Beranová, Denisa ; Šiler, Pavel (referee) ; Opravil, Tomáš (advisor)
The bachelor thesis deals with possibilities of utilization of solid residues from fluidized bed combustion of coal, bed and filter ash, to be used in the production of composite Portland cements. 6 ash types were investigated, of which 3 were bed ash (finely ground) and 3 were filter ash colected from Ledvice, Tisová and Poříčí K8 power plants. The chemical composition of the ash collected was determined and the progress of a hydration reaction monitored, and then samples mixed with Portland clinker were prepared. Their respective compressive strength and flexural strength were then analysed and observations made on the hydration and composition of products of the hydration reaction. Finally the results of selected mixtures were verified with prepared standardized mortars.
|
|
|
Study of the influence of compositon on the mechanical properties of high performance concrete
Veleba, Ondřej ; Šoukal, František (referee) ; Krátký, Josef (advisor)
This work is devoted to study the influence of the composition on mechanical properties of high performance concret based on portland cement. 29 samples of high performance concrete (HPC) warying in composition were prepared. The constituents used for HPC preparation were: cement Aalborg White, silica fume, finelly ground blast furnace slag, finelly ground silica, calcinated bauxite and polycarboxylate based superplasticizer. The mechanical parameters (flexural and compressive strength) of the samples were observed after 7 and 28 days of moist curing. Compressive strength values after 28 days were in the range of 92 to 194 MPa and the flexural strength values were in the range of 7 to 23 MPa (without using of fiber reinforcement). The graphs showing mechanical parameters depending on the mixture composition were constructed and consequently evaluated.
|
|
|
Possibilities of utilization of brick-grind-dust in systems based on portland cement
Palovčík, Jakub ; Kalina, Lukáš (referee) ; Opravil, Tomáš (advisor)
This thesis deals with possibilities of using brick-grind-dust which is a secondary product from manufacturing of grinded bricks. A boom in this method of masonry is connected with an increase of production of these secondary materials. These secondary materials are partly returned to brick manufacturing and partly buried in a landfill site. Due to their composition and origin, these materials are potentially pozzolan active, making them interesting for applications in hydraulic binders. The aim of the work was to study the physical and chemical properties of several brick-grind-dust and brick sands. Subsequently, binders based on these materials and Portland cement were prepared. The properties of the binders were modified by means of adding a commercially available polycarboxylate superplasticizer. The development of mechanical properties of the prepared binders has been studied over time. Hydration of the selected binders was analyzed by isothermal calorimetry.
|
|
|
Influence of zinc on mechanical properties of cement composites
Štarha, Tomáš ; Šilerová,, Iva (referee) ; Šiler, Pavel (advisor)
The theme of this bachelor thesis is to monitor the effect of zinc on mechanical properties of portland cement. Zinc was tested in the form of zinc oxide. Three acceleration additives were added, calcium oxide, formic acid and calcium formate in various proportions. Furthermore, the mechanical properties of all these mixtures were monitored by measuring flexural strength and compressive strength at 7 and 28 days after mixing and mixtures were analyzed by XRD and DTA. Also using isoperibolic calorimetry, the hydration of CEM 42.5 R cement zinc oxide was monitored.
|
|
| |
|
|
Possibilities of hexavalent chromium reduction within portland cement hydration
Mončeková, Miroslava ; Koplík, Jan (referee) ; Šoukal, František (advisor)
The issue of Hexavalent chromium toxicity to Portland cement hydration is a very actual these days. It takes much effort to obtain a cement containing Cr(VI) less than 2 ppm. The primary objective of this diploma theses is to find appropriate reducing substances and specify their efficiency, as well as to make an attempt to optimize their dosage. As reducing substances there were plumbed sulphites and tin(II) salts. The influence of reducing substances applied to the hydration and cement properties were validated by strenght tests, the calorimetric measurement and the volume-variation measurement. And also the changes in hydration products microstructure of Portland clinker after the gypsum replacement by sulphite ions were plumbed. The study of microstructure is based on SEM and XRD methods.
|
|
|
Influence of calcium sulphate type on hydration of Portland cement
Šimčíková, Ivana ; Šiler, Pavel (referee) ; Šoukal, František (advisor)
My bachelor thesis deals with the study of the influence of calcium sulphate types on the hydration of Portland cement. Hydration is performed at 15 °C, 25 °C and 40 °C. In the theoretical part we find a description of the hydration of Portland cement and the influence of the type and amount of gypsum on the hydration period. The experimental part contains the preparation of samples for measurement and the principle of calorimetry including a description of the calorimetric curve. The data obtained from the calorimetric curve was processed into ternary diagrams for illustration. The diagrams show that the more calcium sulphate is soluble, the shorter the induction period, the times of reaching the minimum heat flow and heat flow at the maximum silicate peak will have. Further, the diagrams showed that as the amount of water in sulphate increases, so does the amount of hydration heat released.
|
|
|
The thermodynamic stability of etringite
Magrla, Radek ; Durica,, Tibor (referee) ; Bílek,, Vlastimil (referee) ; Brauner,, Josef (referee) ; Fridrichová, Marcela (advisor)
The theoretical part of this doctoral thesis summarizes the current knowledge of portland cement and its manufacturing technology, information of FBC ash, Aft phases, AFm phases and the current knowledge of thermodynamic stability of ettringite. The practical part of the doctoral thesis focuses on manufacturing of ettringite based on yeelimite clinker, studying the influence of environment on thermodynamic stability of ettringite and manufacturing of ettringite by direct addition of calcium hydroxide and aluminum sulfate.
|
guest ::
