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The influence of crystallization additives to waterproof concrete
Rosecký, Pavel ; Louda, Pavel (referee) ; Hela, Rudolf (advisor)
This bachelor´s thesis deals with influence of crystallization additives to waterproof concrete. In the theoretical part is detailed analysis individual components in concrete production, improving waterproofing properties and finally functions and properties of crystallization materials. In the practical part I deal with influence of selected crystallization additives on properties of fresh and hardened concrete.
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Properties and the Use of Metal Foams
Křivánek, Robin ; Liškutín, Petr (referee) ; Němec, Karel (advisor)
In this thesis are summarized the findings of metal foams, with prevailing constraints on aluminum foam, because in them hides the greatest potential. The first part is described the production of porous materials, especially the way of floam production by thermal decomposition of floaming agent and melt gas injection. There are also written stress tests to gain a deeper knowledge of their properties, but also the latest exploring methods of foams, such as using a radioscopiy and CT scanner from which then creates a voxel model of foam. They are summarized here the basic ways of processing. Finally we must mention the possibility of using these materials with a focus on commercially produced foams Alporas® and Duocel®. Mass using foams mainly prevents high production costs and in some cases difficult reproducibility of properties.
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Aluminium foams and their applications in engineering practice
Belák, Kristián ; Čížek, Jan (referee) ; Němec, Karel (advisor)
Bachelor thesis includes knowledge of aluminum foams and their practical use. The first part of the thesis is focused on the basic characteristics of aluminum and its alloys, consequently, there are characterized metal foams and stated their basic division. Further, there is also devoted considerable attention to selected methods of its manufacturing. Also, properties of these foams are mentioned, mainly the most important ones – mechanical. Thesis deals even about technological processing of foams and the last part contains description of selected applications of metal foams in technical practice.
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Study of alkali metals ions diffusion in hardened cement
Doležal, Martin ; Janča, Martin (referee) ; Šoukal, František (advisor)
This master thesis is aim to study alkali diffusion (sodium, potassium) in hardened cement paste body. It´s deal with impact of various sorroudings (hydroxide, nitrate and carbonate) in various concentrations and temperature effect. This work is also deal with changes in cement paste and medium. Teoretic part is talking about cement production and cement chemistry, alkali-silica reaction, plasticizer, diffusion an cement testing metods. This work is aimed to white (Aalborg CEM I 52,5 R – SR 5) and road (Mokrá CEM I 42,5 R – sc) cement. Experimental part describes constitution of tested cement pastes, conservation of them and sampling. Diffusion is study by ICP-AES which affected the loss of alkali from the solution and SEM which affected alkali migration (diffusion) in cement paste. In several cases, the formation of a saturated alkali edge was observed, followed by steady diffusion. In the case of potassium there was very slow diffusion through the body mass. The influence of medium and temperature was evaluated as the most significant. The effect of medium concentration wasn´t significant. Also changes in the porosity on the body were observed. The diffusion itself was affected by secondary products gorwing on the surface of body and in the medium. The work deals with them in the last part.
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Impact of input parameters variation on fabrication of nanoporous alumina
Hriczo, Filip ; Macháčková, Marina (referee) ; Hrdý, Radim (advisor)
This thesis examines and tests acids and conditions, which make the production of nanoporous ceramic at the thin aluminium layer the most effective and provide the highest quality. This paper describes the production of nanoporous structures with pore size 15-400 nm, depending on the electrolyte. Creating a regular hexagonal structure by electrochemical oxidation is dependent on many parameters that affect the regularity of structure and parameters of the ceramics produced. They were investigated primarily by changes in temperature and input voltage. All results were examined by SEM analysis.
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Study of alkali metals ions diffusion in hardened cement
Doležal, Martin ; Janča, Martin (referee) ; Šoukal, František (advisor)
This master thesis is aim to study alkali diffusion (sodium, potassium) in hardened cement paste body. It´s deal with impact of various sorroudings (hydroxide, nitrate and carbonate) in various concentrations and temperature effect. This work is also deal with changes in cement paste and medium. Teoretic part is talking about cement production and cement chemistry, alkali-silica reaction, plasticizer, diffusion an cement testing metods. This work is aimed to white (Aalborg CEM I 52,5 R – SR 5) and road (Mokrá CEM I 42,5 R – sc) cement. Experimental part describes constitution of tested cement pastes, conservation of them and sampling. Diffusion is study by ICP-AES which affected the loss of alkali from the solution and SEM which affected alkali migration (diffusion) in cement paste. In several cases, the formation of a saturated alkali edge was observed, followed by steady diffusion. In the case of potassium there was very slow diffusion through the body mass. The influence of medium and temperature was evaluated as the most significant. The effect of medium concentration wasn´t significant. Also changes in the porosity on the body were observed. The diffusion itself was affected by secondary products gorwing on the surface of body and in the medium. The work deals with them in the last part.
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Effect of Type of Air-Entraining Admixtures on the Properties of Concrete
Pikna, Ondřej ; Ťažký, Martin ; Hela, Rudolf
One of the elementary factor that must be taken into account when designing concrete is its durability. The exposition, which is significantly connected with the durability of hardened concrete, is also the effect of negative temperatures together with the possibility of combination with salts. The present article tries to clarify and compare the currently used air entraining admixtures for concrete, which aim to improve the properties and especially the durability in the mentioned exposition.
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The influence of crystallization additives to waterproof concrete
Rosecký, Pavel ; Louda, Pavel (referee) ; Hela, Rudolf (advisor)
This bachelor´s thesis deals with influence of crystallization additives to waterproof concrete. In the theoretical part is detailed analysis individual components in concrete production, improving waterproofing properties and finally functions and properties of crystallization materials. In the practical part I deal with influence of selected crystallization additives on properties of fresh and hardened concrete.
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|
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Aluminium foams and their applications in engineering practice
Belák, Kristián ; Čížek, Jan (referee) ; Němec, Karel (advisor)
Bachelor thesis includes knowledge of aluminum foams and their practical use. The first part of the thesis is focused on the basic characteristics of aluminum and its alloys, consequently, there are characterized metal foams and stated their basic division. Further, there is also devoted considerable attention to selected methods of its manufacturing. Also, properties of these foams are mentioned, mainly the most important ones – mechanical. Thesis deals even about technological processing of foams and the last part contains description of selected applications of metal foams in technical practice.
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Impact of input parameters variation on fabrication of nanoporous alumina
Hriczo, Filip ; Macháčková, Marina (referee) ; Hrdý, Radim (advisor)
This thesis examines and tests acids and conditions, which make the production of nanoporous ceramic at the thin aluminium layer the most effective and provide the highest quality. This paper describes the production of nanoporous structures with pore size 15-400 nm, depending on the electrolyte. Creating a regular hexagonal structure by electrochemical oxidation is dependent on many parameters that affect the regularity of structure and parameters of the ceramics produced. They were investigated primarily by changes in temperature and input voltage. All results were examined by SEM analysis.
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