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Leachability of Ba and Cr from alkali-activated matrices
Cába, Vladislav ; Hajzler, Jan (referee) ; Koplík, Jan (advisor)
The aim of this work is to determine the usability of alkaline activated matrices made from ashes to inhibition of barium and chrome. Ashes – fly ashes and ashes from fluidized bed combustion – were compared with cement used for inhibition. By using inductively coupled plasma atomic emmission spectrometer were determined concentrations of barium and chrome in leachates based on norm ČSN EN – 12457-4. In addition, images were taken on the scanning electron microscope and crystallographic spectra from X-ray crystalography were obtained to determine structure. The results show that ashes from fluidized bed combustion are suitable for inhibition of both barium and chrome, whereas fly ashes can not sustain these elements with such success.
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Preparation of geopolymeric binders based on power plant fly ashes
Jevická, Lucie ; Opravil, Tomáš (referee) ; Šoukal, František (advisor)
This thesis deals with preparation of geopolymeric binders based on power plant fly ashes by alkali activation. It studies influence of different types ashes content in pastes on setting and final properties of geopolymeric binders. The aim of study is determination of optimal ratio of raw materials to reach the best possible characteristics of final binder. Ashes from high-temperature and fluidized bed coal combustion were used for experimental works. Mass content of ashes in tested mixtures and total ratio of oxides crucial for polycondensation and geopolymeric structure formation were chosen as major input parameters. Calorimetric measurements of tested mixtures fresh pastes were implemented to learn about setting process. Hardened binder specimens were tested for bending and compressive strength.
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Leachability of Ba and Cr from alkali-activated matrices
Cába, Vladislav ; Hajzler, Jan (referee) ; Koplík, Jan (advisor)
The aim of this work is to determine the usability of alkaline activated matrices made from ashes to inhibition of barium and chrome. Ashes – fly ashes and ashes from fluidized bed combustion – were compared with cement used for inhibition. By using inductively coupled plasma atomic emmission spectrometer were determined concentrations of barium and chrome in leachates based on norm ČSN EN – 12457-4. In addition, images were taken on the scanning electron microscope and crystallographic spectra from X-ray crystalography were obtained to determine structure. The results show that ashes from fluidized bed combustion are suitable for inhibition of both barium and chrome, whereas fly ashes can not sustain these elements with such success.
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|
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Preparation of geopolymeric binders based on power plant fly ashes
Jevická, Lucie ; Opravil, Tomáš (referee) ; Šoukal, František (advisor)
This thesis deals with preparation of geopolymeric binders based on power plant fly ashes by alkali activation. It studies influence of different types ashes content in pastes on setting and final properties of geopolymeric binders. The aim of study is determination of optimal ratio of raw materials to reach the best possible characteristics of final binder. Ashes from high-temperature and fluidized bed coal combustion were used for experimental works. Mass content of ashes in tested mixtures and total ratio of oxides crucial for polycondensation and geopolymeric structure formation were chosen as major input parameters. Calorimetric measurements of tested mixtures fresh pastes were implemented to learn about setting process. Hardened binder specimens were tested for bending and compressive strength.
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