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Setting control of alkali-activated systems
Komosná, Kateřina ; Novotný, Radoslav (referee) ; Kalina, Lukáš (advisor)
This thesis is focused on the possibilities of setting control of alkali-activated systems based on blast furnace slag. The aim of this work is finding the suitable retarder that most extends the time of setting and also preserves the mechanical properties of alkali-activated material. In experimental section were prepared samples of blast furnace slag, water glass, water and additives in various weight addition. Testing samples have undergone of flexural and compressive strength tests. Then the setting time was determined using the Vicat device. The samples were measured calorimetrically because of monitoring the setting process. Finally the mixtures were observed using scanning electron microscope for a closer view on the structure of samples and distribution of setting retarder.
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On the mechanisms of shrinkage reducing admixtures in alkali activated materials
Komosná, Kateřina ; Bartoníčková, Eva (referee) ; Kalina, Lukáš (advisor)
This thesis is focused on the principles of behavior of shrinkage reducing agents (SRA) in alkali-activated materials based on blast furnace slag. The main focus of this work is selecting the most suitable admixture based on experiments, by which will be achieved through minimal shrinkage and will have negative effect on the properties of alkali-activated blast furnace slag at the same time. In experimental section of this work, the surface tension as individual additives as their mixtures with pore solution were measured primarily. Then the testing samples composed of blast furnace slag, water glass and addition of SRA were prepared. Of these samples was measured shrinkage and weight loss. Moreover, their mechanical properties such as flexural and compressive strength were monitored. Next, the beginning and the end of solidification was studied using the Vicat device and last but not least workability. The hydration process of alkali-activated materials with SRA was measured calorimetrically. Finally the microstructure in prepared samples was observed using scanning electron microscopy (SEM-EDS) and the total porosity was determined by mercury porosimeter.
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On the mechanisms of shrinkage reducing admixtures in alkali activated materials
Komosná, Kateřina ; Bartoníčková, Eva (referee) ; Kalina, Lukáš (advisor)
This thesis is focused on the principles of behavior of shrinkage reducing agents (SRA) in alkali-activated materials based on blast furnace slag. The main focus of this work is selecting the most suitable admixture based on experiments, by which will be achieved through minimal shrinkage and will have negative effect on the properties of alkali-activated blast furnace slag at the same time. In experimental section of this work, the surface tension as individual additives as their mixtures with pore solution were measured primarily. Then the testing samples composed of blast furnace slag, water glass and addition of SRA were prepared. Of these samples was measured shrinkage and weight loss. Moreover, their mechanical properties such as flexural and compressive strength were monitored. Next, the beginning and the end of solidification was studied using the Vicat device and last but not least workability. The hydration process of alkali-activated materials with SRA was measured calorimetrically. Finally the microstructure in prepared samples was observed using scanning electron microscopy (SEM-EDS) and the total porosity was determined by mercury porosimeter.
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Setting control of alkali-activated systems
Komosná, Kateřina ; Novotný, Radoslav (referee) ; Kalina, Lukáš (advisor)
This thesis is focused on the possibilities of setting control of alkali-activated systems based on blast furnace slag. The aim of this work is finding the suitable retarder that most extends the time of setting and also preserves the mechanical properties of alkali-activated material. In experimental section were prepared samples of blast furnace slag, water glass, water and additives in various weight addition. Testing samples have undergone of flexural and compressive strength tests. Then the setting time was determined using the Vicat device. The samples were measured calorimetrically because of monitoring the setting process. Finally the mixtures were observed using scanning electron microscope for a closer view on the structure of samples and distribution of setting retarder.
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