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Optimization of the concrete composition with the use of recycled concrete aggregates
Skriňáková, Eva ; Holák, Michal (referee) ; Hela, Rudolf (advisor)
Concrete as a building material is subject to continuous innovation and thanks to advanced technology and quantum of research, its properties are still improved. It is logical that the more concrete we produce, the more waste it arises. The volume of this waste can not be stored in landfills endlessly, nowadays most of the waste economies in the world are trying to recycle concrete rubble. The recycling is not such a problem, the technology has been long verified but the quality of the recycled concrete aggregate is unquestionably one of the primary assumption which leads to accomplish required properties of concrete. In fact, the recycling process is „crushing“ the concrete into particles with an effort to eliminate the cement paste on the surface of the aggregate. An ideal solution would be create a resistant and firm coating that would adhere perfectly to the cement matrix. This diploma thesis is focused on the properties of recycled concrete aggregate and methods of improvement and optimization of the concrete mix composition.
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The leachability of metals from geopolymers using various leaching mediums
Bystrianska, Emília ; Beranová, Denisa (referee) ; Koplík, Jan (advisor)
The aim of this work is the comparison of the leachability of metal from AAM due to the use of various leaching mediums. The ability to stabilize 1 wt. % Pb2+ in alkali-activated matrices was compared using different leaching tests (ČSN EN 12457, HJ-T/299, TCLP). The concentration of metal content in leachate was determined by ICP-OES method. The matrices consisted of blast-furnace slag and high-temperature fly ash. Lead distribution in matrices was analyzed by SEM microscopy. Furthermore, the effect of mechanical strength and pH leachate on the lead concentration were examined.
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Effect of active ingredients to the activity of cementing compound with non-alkaline accelerator additive for sprayed concrete.
Závacký, Jakub ; Hela,, Vlastimil (referee) ; Hela, Rudolf (advisor)
The bachelor thesis deals with the problems of the sprayed concrete with the focus on usage of the active ingredients with non-alkaline accelerator additive. The theoretical part covers the current level of knowledge of how the active ingredients are used in the sprayed concrete and their influence on the process of hydration. In the experimental part the reactivity of cementing compound with non-alkaline accelerator on the basis of aluminium sulphate were compared in a laboratory when the active ingredients (such as slag, fly-ash and very fine limestone) were used. The cements CEM I 42,5 R, made by different producers were verified on the basis of the setting time and early strength gain using the Vicat needle to examine the mechanical properties after 6 and 24 hours.
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Effect of active ingredients to the activity of cementing compound with non-alkaline accelerator additive for sprayed concrete.
Závacký, Jakub ; Hela,, Vlastimil (referee) ; Hela, Rudolf (advisor)
The bachelor thesis deals with the problems of the sprayed concrete with the focus on usage of the active ingredients with non-alkaline accelerator additive. The theoretical part covers the current level of knowledge of how the active ingredients are used in the sprayed concrete and their influence on the process of hydration. In the experimental part the reactivity of cementing compound with non-alkaline accelerator on the basis of aluminium sulphate were compared in a laboratory when the active ingredients (such as slag, fly-ash and very fine limestone) were used. The cements CEM I 42,5 R, made by different producers were verified on the basis of the setting time and early strength gain using the Vicat needle to examine the mechanical properties after 6 and 24 hours.
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The leachability of metals from geopolymers using various leaching mediums
Bystrianska, Emília ; Beranová, Denisa (referee) ; Koplík, Jan (advisor)
The aim of this work is the comparison of the leachability of metal from AAM due to the use of various leaching mediums. The ability to stabilize 1 wt. % Pb2+ in alkali-activated matrices was compared using different leaching tests (ČSN EN 12457, HJ-T/299, TCLP). The concentration of metal content in leachate was determined by ICP-OES method. The matrices consisted of blast-furnace slag and high-temperature fly ash. Lead distribution in matrices was analyzed by SEM microscopy. Furthermore, the effect of mechanical strength and pH leachate on the lead concentration were examined.
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|
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Optimization of the concrete composition with the use of recycled concrete aggregates
Skriňáková, Eva ; Holák, Michal (referee) ; Hela, Rudolf (advisor)
Concrete as a building material is subject to continuous innovation and thanks to advanced technology and quantum of research, its properties are still improved. It is logical that the more concrete we produce, the more waste it arises. The volume of this waste can not be stored in landfills endlessly, nowadays most of the waste economies in the world are trying to recycle concrete rubble. The recycling is not such a problem, the technology has been long verified but the quality of the recycled concrete aggregate is unquestionably one of the primary assumption which leads to accomplish required properties of concrete. In fact, the recycling process is „crushing“ the concrete into particles with an effort to eliminate the cement paste on the surface of the aggregate. An ideal solution would be create a resistant and firm coating that would adhere perfectly to the cement matrix. This diploma thesis is focused on the properties of recycled concrete aggregate and methods of improvement and optimization of the concrete mix composition.
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