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Study of microstructure of autoclaved aerated concrete with using of secondary raw materials
Martanová, Jana ; Suchý, Peter (referee) ; Kulísek, Karel (advisor)
Autoclaved aerated concrete is a used building material, especially for its thermal insulating properties. During autoclaving, an aerated concrete microstructure produces crystalline CSH phases, primarily tobermorite. The ingoing substances are calcium oxide and silica. In addition to commonly used raw materials, secondary raw materials rich in silicon dioxide can be used for production. The use of secondary raw materials gives the opportunity for the construction industry to be more environmentally friendly. Another benefit is the reduction of financial costs. The work explores the influence of individual secondary raw materials on the microstructure. High-temperature fly ash, fluid fly ash, cinder, ground glass and zeolite were used The raw materials were mixed with unalloyed lime at a molar ratio of calcium oxide to silicon dioxide of 0.73 and 1.0. Autoclaving capsules were used to synthesize tobermorite under laboratory conditions. Autoclave was performed at 170 °C and 190 °C with hydrothermal durations of 4, 8 and 16 hours. The most important influence on the microstructure was high-temperature fly ash, on the contrary, the greatest influence on the mechanical properties is attributed to the ground glass.
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Specific cement composite based on secondary raw materials with emphasis on durability
Figala, Petr ; Dohnálek,, Pavel (referee) ; Drochytka, Rostislav (advisor)
Nowadays the attention to the utilization of secondary raw materials as a component of building materials is being paid to in the Czech Republic and in the world. This thesis deals with possibilities of using secondary raw materials as partial cement substitutes in industrial floors. The aim of this thesis is to verify the influence of cement substitution amount with secondary raw materials and their fineness of grinding on the properties of the floor surface in time and on its structure. On the basis of the acquired knowledge, the influence of the pre-treatment of the secondary raw material on the properties of the floor ceiling with an emphasis on the economic aspect was assessed. After evaluating the results, some substitution of cement in the floor screed with secondary raw materials is beneficial. The significant influence of more intensive milling of the floor screeds base on the parameters of the final floor screed was not confirmed. It seems, that it is possible to achieve very good results even when using secondary raw materials with a lower percentage of fine particles. This brings together the economic benefits of lowering the cost of a lower dose of expensive cement by using cheaper secondary raw materials, because pre-treatment of such materials does not require the use of a large amount of energy.
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Study of microstructure of autoclaved aerated concrete with using of secondary raw materials
Martanová, Jana ; Suchý, Peter (referee) ; Kulísek, Karel (advisor)
Autoclaved aerated concrete is a used building material, especially for its thermal insulating properties. During autoclaving, an aerated concrete microstructure produces crystalline CSH phases, primarily tobermorite. The ingoing substances are calcium oxide and silica. In addition to commonly used raw materials, secondary raw materials rich in silicon dioxide can be used for production. The use of secondary raw materials gives the opportunity for the construction industry to be more environmentally friendly. Another benefit is the reduction of financial costs. The work explores the influence of individual secondary raw materials on the microstructure. High-temperature fly ash, fluid fly ash, cinder, ground glass and zeolite were used The raw materials were mixed with unalloyed lime at a molar ratio of calcium oxide to silicon dioxide of 0.73 and 1.0. Autoclaving capsules were used to synthesize tobermorite under laboratory conditions. Autoclave was performed at 170 °C and 190 °C with hydrothermal durations of 4, 8 and 16 hours. The most important influence on the microstructure was high-temperature fly ash, on the contrary, the greatest influence on the mechanical properties is attributed to the ground glass.
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Specific cement composite based on secondary raw materials with emphasis on durability
Figala, Petr ; Dohnálek,, Pavel (referee) ; Drochytka, Rostislav (advisor)
Nowadays the attention to the utilization of secondary raw materials as a component of building materials is being paid to in the Czech Republic and in the world. This thesis deals with possibilities of using secondary raw materials as partial cement substitutes in industrial floors. The aim of this thesis is to verify the influence of cement substitution amount with secondary raw materials and their fineness of grinding on the properties of the floor surface in time and on its structure. On the basis of the acquired knowledge, the influence of the pre-treatment of the secondary raw material on the properties of the floor ceiling with an emphasis on the economic aspect was assessed. After evaluating the results, some substitution of cement in the floor screed with secondary raw materials is beneficial. The significant influence of more intensive milling of the floor screeds base on the parameters of the final floor screed was not confirmed. It seems, that it is possible to achieve very good results even when using secondary raw materials with a lower percentage of fine particles. This brings together the economic benefits of lowering the cost of a lower dose of expensive cement by using cheaper secondary raw materials, because pre-treatment of such materials does not require the use of a large amount of energy.
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