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Effect of activator type on rheology of alkali-activated slag
Markusík, David ; Smilek, Jiří (referee) ; Bílek, Vlastimil (advisor)
This work deals with rheology of alkali-activated slag pastes (AAP) because of importance of these properties in building connectors for processing and application. The effects of different concentrations of sodium and potassium hydroxides activation solutions on the rheological properties of prepared AAP are examined. For the basic characterization of activation solutions, rotational and rheological measurements of AAS were made, and were compared to measurements from the flow table. Dependences of setting time on the activator concentration and rheological and calorimetric monitoring of hydration progress were also investigated. The findings prove a major influence of concentration and activator type on any determinations made. In pastes activated by potassium hydroxide, fluidity increases with increasing concentration, which correlates with increases in values on the shake table. In case of sodium hydroxide, with the increasing concentration, fluidity increases up to 25 wt. %. The following sharp reduction in fluidity correlates to the values on the flow table as well as with the storage modulus courses from oscillation measurements. In the first minutes after mixing, there was evidence of a sharper increase in yield point for pastes with higher activator concentrations.
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Effect of activator type on rheology of alkali-activated slag
Markusík, David ; Smilek, Jiří (referee) ; Bílek, Vlastimil (advisor)
This work deals with rheology of alkali-activated slag pastes (AAP) because of importance of these properties in building connectors for processing and application. The effects of different concentrations of sodium and potassium hydroxides activation solutions on the rheological properties of prepared AAP are examined. For the basic characterization of activation solutions, rotational and rheological measurements of AAS were made, and were compared to measurements from the flow table. Dependences of setting time on the activator concentration and rheological and calorimetric monitoring of hydration progress were also investigated. The findings prove a major influence of concentration and activator type on any determinations made. In pastes activated by potassium hydroxide, fluidity increases with increasing concentration, which correlates with increases in values on the shake table. In case of sodium hydroxide, with the increasing concentration, fluidity increases up to 25 wt. %. The following sharp reduction in fluidity correlates to the values on the flow table as well as with the storage modulus courses from oscillation measurements. In the first minutes after mixing, there was evidence of a sharper increase in yield point for pastes with higher activator concentrations.
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Measurement of mechanical properties of thin films by nanocompression
Kuběna, Ivo ; Kruml, Tomáš ; Hutař, Pavel ; Boháč, Petr ; Stranyánek, Martin ; Čtvrtlík, Radim ; Pánek, P. ; Vystavěl, T.
Mechanical properties of thin films are not easy to be measured. This is particularly true in the case of plastic properties as the yield point, the work hardening rate or the ultimate stress. Nevertheless, such parameters are needed e.g. in the design of integrated circuits where the thermal stresses may lead to mechanical failure of the component. We applied two modern experimental facilities, the focused ion beam and the nanoindentation for exact measurement of plastic properties of a Al-1.5%Cu thin film prepared by PVD, used for electrical connection of integrated circuits. By FIB milling, cylindrical specimens were prepared. The height of the specimens was equal to the film thickness (2 m) and their diameter was about 1.3 m. These specimens were subjected to the compressive loading using the nanoindenter equipped by a flat punch. Stress-strain curves of the film were obtained rather precisely.
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