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Composite materials based on alcali activated blast furnace slag with admixture of fly ash
Indra, Ivo ; Brandštetr, Jiří (referee) ; Opravil, Tomáš (advisor)
This thesis concerns on substitution of blast furnace slag or its part with fly ash in alkali-activated systems based on aluminosilikates. Classic, fluid bottom and fluid filter fly ashes will be tested. The goal is to prepare geopolymer with required mechanical properties, but with maximal admixture of alternative raw materials. In composites with substitutioned slag or its part the thesis focuses mainly on workabilityof fresh mixture, pressure and bending strenght. Use of secondary raw materials has advantages in the economic point of view and it´s friendly to enviroment, too.
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Water soluble foundry binders with heat hardening
Vaverka, Jiří ; Rusín, Karel (referee) ; Cupák, Petr (advisor)
This thesis is focused on water soluble foundry binders with heat hardening. The thesis comprises general description of moulding mixtures, the description of the most common methods used for heat hardening and primarily the list of current and alternative binders, which reduce negative environmental impact of foundries. Also their qualities, benefits and drawbacks are included.
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Comparison of environmental and technological properties of various methods of manufacture of foundry moulds and cores
Dlouhá, Monika ; Rusín, Karel (referee) ; Cupák, Petr (advisor)
The roots of foundry manufacture perhaps go back to 2000 BC. Since foundry production in its development has undergone four stages and each of them there was a qualitative jump. From 20 century, the chemicals used in foundry moulds and cores which is the cause producing harmful substances that have a negative impact on the environment. Major sources of harmful substances are just binders, hardeners and catalysts that are needed for bonding of moulding mixture. The third stage deals with the foundry physical processes that are not using today, even though they are most ecological. Nowadays the most used methods Cold-box, Warm-box and Hot-box.
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Water soluble foundry binder with heat hardening
Prokop, Tomáš ; Burianová, Klára (referee) ; Cupák, Petr (advisor)
Foundry production produces the biggest amount of dangerous waste, which has a negative impact on environment and working conditions in the foundry. The foundry engineers test new technologies of shaping mixtures with new binders to protect environment and working conditions. We can reduce the production of dangerous waste by using better technologies and less harmful materials, which are needed for modeling forms and cores. The large source of pollution are binders, hardeners and catalyzer needed for binding sand. This work is focused on new types of ecological binders, which are dissolvable in water and are formed by setting temperature. These binders are ecological variants of known inorganic and organic binders.
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Utilization possibilitiesof foundry sands in geopolymers systems
Kopecký, Filip ; Másilko, Jiří (referee) ; Opravil, Tomáš (advisor)
Considering increasing manufacture of cast iron, steels and other metallic materials made in foundries increases also production of waste foundry sands. Foundry sands that remain after moulding and can not be reused in the prouction process are usually not recycled nowadays and in the better cases they are clasified as a fill materials. Becouse these secondary raw materials are produced in relatively big amounts it is apropriate to search for their effective reuse. One of the possibilities is using of this materials in buliding industry. Thanks to their constitution and properties we can consider the possibilties of an alkaline activation. Thats why this work discusses the possibilities of the alkaline activation of the waste foundry sands.
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Possibilities of alcali activation of steel slag
Frýbortová, Iva ; Rovnaník, Pavel (referee) ; Opravil, Tomáš (advisor)
The properties of alkali activated steel slag as a clinker-free binder system was studied in this thesis. The aim was to find the optimal composition of alkaline activator providing good properties of the prepared binder. Sodium and potassium hydroxides and alkaline silicates in the form of solutions and powders were used as the activators. Mixture of steel slag, fluidized bed coal combustion ash and water without any activating ingredient was another binder system studied in this work. Mechanical properties, such as compressive and flexural strength, of the mixtures were determined. Calorimetric measurements were used for the study of hydration process, scanning electron microscopy for the examination of microstructure.
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Study of synthetic sandstones preparation possibilities
Solik, Jaroslav ; Kalina, Lukáš (referee) ; Opravil, Tomáš (advisor)
This thesis explores the possibility of developing synthetic sandstones based on alkaline-activated (geopolymer) binders. The goal is to design an appropriate connective system of optimal concentration, so that the prepared material (artificial stone) showed similar characteristics as natural. The experimental section summarizes the experiments that explore several different alkali connective systems. The aim is to compare the properties of binders prepared from methakaolin (Mefisto K-05 and L-05) alkali-activated by sodium or potassium water glass. For comparison with these connective systems were also prepared samples of commercially supplied geopolymer binder called Baucis
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