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DIFFERENT TYPES OF CONCRETE ADMIXTURES AND THEIR EFFECT ON PROPERTIES OF FRESH AND HARD SPRAYED CONCRETE
Hela, Vlastimil ; Brožovský, Jiří (advisor)
The current technology for sprayed concrete cannot do without various types of concrete admixtures allowing that more demanding requirements for quality and overall characteristics of Sprayed Concrete can be met. These are mainly concrete plastificators and set acceleration admixtures. In practice these technologies are employed especially in construction of underground structures where the working conditions are often very restricted. In these days Sprayed Concrete is usually applied by wet spraying where the fresh concrete is made in a batching plant and then transported to the construction site. That is why it is also important to pay attention to rheology characteristics of sprayed concrete. The concrete is then placed by a special spraying plant while it is ensured that all requirements and technical specifications for sprayed concrete are complied with. The characteristics are most affected by the admixtures - both plastificators and accelerators and their compatibility with cement. In order to acquire new evidence in the field of sprayed concrete technology and use of admixtures and their effect in relation with various types of cement a number of combinations of admixtures and cements were tested. Gradually results were obtained and recorded for rheology of cement mortars and concrete, for characteristics of young sprayed concrete mixes and for the comparison between the laboratory tests and findings from daily practice.
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Activation admixtures in concrete
Eger, Lukáš ; Hela, Vlastimil (referee) ; Hela, Rudolf (advisor)
The aim of my bachelor´s work is the summarization and focus on admixure concrete,and the active and inert admixure, which have some positive characteristies for fresh and hardened concrete. Theoretically, I tried to study the increase of their joining potential while this characteristic can be used by either chemici or mechnical way, their combination as well. I also Works on evaluetion of physically mechanical influence for fresh and hardened concrete that can up to 60 days old while the cement was partly substituted by admixure of different character.
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Study of the development, trends and innovations in shotcrete technology
Záruba, Jiří ; Hela, Vlastimil (referee) ; Hubáček, Adam (advisor)
The Bachelor thesis is focused on the study of development, trends and innovations in shotcrete technology. The main target of this thesis is to summarize new procedures in shotcrete technology. Secondary targets include a description of basic properties of sprayed concrete, introducing new trends and technology in recent years. The next sub-goal is to propose experiment that will try new ways of testing shotcrete. Based on these secondary targets is possible to evaluate the current situation in shotcrete technology and fulfil the main objective of this thesis.
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DIFFERENT TYPES OF CONCRETE ADMIXTURES AND THEIR EFFECT ON PROPERTIES OF FRESH AND HARD SPRAYED CONCRETE
Hela, Vlastimil ; Brožovský, Jiří (advisor)
The current technology for sprayed concrete cannot do without various types of concrete admixtures allowing that more demanding requirements for quality and overall characteristics of Sprayed Concrete can be met. These are mainly concrete plastificators and set acceleration admixtures. In practice these technologies are employed especially in construction of underground structures where the working conditions are often very restricted. In these days Sprayed Concrete is usually applied by wet spraying where the fresh concrete is made in a batching plant and then transported to the construction site. That is why it is also important to pay attention to rheology characteristics of sprayed concrete. The concrete is then placed by a special spraying plant while it is ensured that all requirements and technical specifications for sprayed concrete are complied with. The characteristics are most affected by the admixtures - both plastificators and accelerators and their compatibility with cement. In order to acquire new evidence in the field of sprayed concrete technology and use of admixtures and their effect in relation with various types of cement a number of combinations of admixtures and cements were tested. Gradually results were obtained and recorded for rheology of cement mortars and concrete, for characteristics of young sprayed concrete mixes and for the comparison between the laboratory tests and findings from daily practice.
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|
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|
|
Study of the development, trends and innovations in shotcrete technology
Záruba, Jiří ; Hela, Vlastimil (referee) ; Hubáček, Adam (advisor)
The Bachelor thesis is focused on the study of development, trends and innovations in shotcrete technology. The main target of this thesis is to summarize new procedures in shotcrete technology. Secondary targets include a description of basic properties of sprayed concrete, introducing new trends and technology in recent years. The next sub-goal is to propose experiment that will try new ways of testing shotcrete. Based on these secondary targets is possible to evaluate the current situation in shotcrete technology and fulfil the main objective of this thesis.
|
|
|
Activation admixtures in concrete
Eger, Lukáš ; Hela, Vlastimil (referee) ; Hela, Rudolf (advisor)
The aim of my bachelor´s work is the summarization and focus on admixure concrete,and the active and inert admixure, which have some positive characteristies for fresh and hardened concrete. Theoretically, I tried to study the increase of their joining potential while this characteristic can be used by either chemici or mechnical way, their combination as well. I also Works on evaluetion of physically mechanical influence for fresh and hardened concrete that can up to 60 days old while the cement was partly substituted by admixure of different character.
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