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The influence of the amount of sulfates on the formation of ettringite in cement-concrete covers
Mrhálková, Leona ; Palovčík, Jakub (referee) ; Opravil, Tomáš (advisor)
This bachelor´s thesis is focused on the influence of the amount of sulfates on the formation of ettringite in cement-concrete covers. For the experiments, samples of cement pastes, mortars, and concretes in the form of small beams were created. Cements of class CEM I 42.5 R – SC were used as the binder. In some mixtures, gypsum from the production of titanium dioxide was added as an additional source of sulfates. To assess the impact of ettringite formation on the properties of the samples, strength tests of the prepared materials were conducted, followed by CHRL tests. The results of these experiments were subsequently confirmed by XRD and EDX analyses along with images from a scanning electron microscope.
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Diagnostics of flooring failures and defects in the housing and civic construction
Vrtal, Roman ; Žítt, Petr (referee) ; Schmid, Pavel (advisor)
The object of the thesis is a description of preparation process, realization and subsequent treatment of floors based on calcium sulphate, including problems related to the issue. The aim of the work is to closely acquaint the reader with methods used in diagnostics of flooring failures and defects in the housing and civic construction, including practical applications of these methods on real structures. The work also includes experimental analysis of a real floor construction during local load effect.
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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.
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Composite hydrogels
Blechová, Dominika ; Smilek, Jiří (referee) ; Venerová, Tereza (advisor)
The content of this bachelor's thesis is research on the topic of composite hydrogels and subsequent research on the rheological properties of prepared hydrogels from the polysaccharide – Gellan, as well as the determination of the properties of hydrogels with the addition of two types of particles – IPA vesicles and a mixture of hydroxyapatite and calcium sulfate particles obtained by the breakdown of PerOssal pellets (PO particles). Hydrogels are prepared with three different concentrations of Gellan – 1%, 1.5% and 2%. The properties of hydrogels prepared in this way were determined using frequency and mainly amplitude tests. Furthermore, two different methods of applying the sample to the measuring plate of the rheometer were compared. The commonly used method of slicing the sample has been replaced by injection application. The injected samples were measured, the results evaluated and compared with the results of the gels applied by slicing.
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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.
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Diagnostics of flooring failures and defects in the housing and civic construction
Vrtal, Roman ; Žítt, Petr (referee) ; Schmid, Pavel (advisor)
The object of the thesis is a description of preparation process, realization and subsequent treatment of floors based on calcium sulphate, including problems related to the issue. The aim of the work is to closely acquaint the reader with methods used in diagnostics of flooring failures and defects in the housing and civic construction, including practical applications of these methods on real structures. The work also includes experimental analysis of a real floor construction during local load effect.
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