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Influence of high temperatures on concrete properties
Klobása, Jan ; Křížová, Klára (referee) ; Sedlmajer, Martin (advisor)
The aim of this bachelor thesis is to study the problem of the behavior of concrete under high temperatures. The theoretical part of the work summarizes the knowledge about the changes that take place in concrete when it is exposed to a high thermal load that simulates the effects of fire. It also summarizes the effect of high temperatures on the behavior of the individual components that make up concrete. Emphasis is placed on describing the possibilities of eliminating concrete damage at high temperatures. Furthermore, the principles of changes and events due to high temperatures simulating the effect of fire are described. The experimental part summarizes the knowledge related to the composition of concrete, the use of different types of fibers, and other measures in loading concrete at high temperatures. Steps influencing the negative impact on the properties and resistance of concrete to high temperatures are also described. Based on the summarized findings, conclusions are formulated.
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Effect of the currently used plasticizers for concrete hydration temperature
Knotová, Kateřina ; Halas, Vladimír (referee) ; Sedlmajer, Martin (advisor)
Plasticizing and superplasticizing admixtures are the key components of nearly every concrete. These admixtures improve workability of mortar and fresh concrete which lead to facilitation of depositing and compaction. Adding of plasticizers or superplasticizers enables to change properties of fresh and hardened concrete, especially to reduce water-cement ratio, thereby increasing strength and durability of concrete or to improve other properties. The main aim of this thesis is to monitor the effect of plasticizing admixtures and their dosage on the rheology and hydration of concrete with emphasis on the development of hydration temperature. The other goal is to examine their strength qualities. Behaviour of plasticizing admixtures is analysed at first on cement pastes, as simple systems, and then verified on concrete.
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Development of lightweight composites based on foam glass with utilization in civil engineering
Bubeník, Jan ; Sedlmajer, Martin (referee) ; Zach, Jiří (advisor)
Theoretical part of diploma thesis deals with progressive building materials, namely with aggregate from foam glass. Resources for production, description of production, properties of aggregate and its utilization are included. Production of lightweight gaping concrete, its properties, risks during its production and utilization in building practice are part of diploma thesis as well. Lightweight gaping concrete was made during practical part. It was produced by combining aggregate from foam glass and cement. Testing of required properties was carried out on these made samples.
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Study of reaction to fire tests for thermal insulating materials
Krivda, Antonín ; Novák, Vítězslav (referee) ; Sedlmajer, Martin (advisor)
This bachelor thesis deals with thermal insulation, it is fire resistance and reactions to fire. The thesis also approaches the testing of thermal insulation materials. In detail, it focuses on the Small flame test, Calorific value determination and the Flameproof test. The test methods were performed on insulators based on polystyrene and mineral wool. The literary research focuses on the fire safety of buildings that have been already insulated.
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Possibilities of utilization fiber-based and secondary easy-renewable raw sources in the production of lightweight building materials
Horáková, Lucie ; Sedlmajer, Martin (referee) ; Zach, Jiří (advisor)
The diploma thesis dealt with the possibilities of of utilization fiber-based and secondary easy-renewable raw sources in the production of lightweight building materials. The theoretical part includes literature search of the researches, which dealt with this issue. Appropriate sources of fibers were selected within the theoretical part and the findings were used in the practical part of the thesis. Within the practical part laboratory measurements and subsequent selection of the most suitable fibers were performed. Laboratory measurements and subsequent selection of the most suitable fibers were performed in the practical part. Subsequently, designs of thermal insulating plasters (with the possibility of using as repairing plasters) were made on the basis of lightweight glass aggregate, to which the production of test specimens was connected. Laboratory tests were performed on fresh and hardened mortars and subsequently evaluated. In conclusion, an economic evaluation and assessment of the competitiveness of the proposed plasters was carried out.
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Possibilities of utilization of aggregate based on glass powder in new building materials
Novák, Jakub ; Sedlmajer, Martin (referee) ; Zach, Jiří (advisor)
The diploma thesis deals with the use of waste glass powder as an aggregate in thermal insulation plasters for AAC. In the theoretical part, the problem of thermal protection of buildings is discussed first. The production and properties of foamed glass are described. Then the research of plasters, their composition and properties was made. Thermal-insulating plasters are specified and their use has been proposed for thermal insulation of building structures. In the practical part, suitable formulations have been proposed in the form of dry plaster and mortar mixtures (SOMS). Test samples were prepared from them. The physical and mechanical properties were measured. These were compared with the requirements set by standards and technical regulations. To get closer to the behavior of plasters on real buildings an AAC wall was built. The individual recipes were applied on it. It was monitored working with plaster and how it held on the masonry. During ripening crack development was observed. Optimization calculation inculded these aspects and it determined the optimal recipe. All designed recipes can be used as a thermal-insulating plasters.
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Possibilities of using lightweight aggregate for lightweight concrete
Jahn, Jeroným ; Přikryl, Jan (referee) ; Sedlmajer, Martin (advisor)
DIPLOMA THESIS IN THEIR THEORETICAL PART ARE FOCUSE , USE LIGHTWEIGHT AGGREGATES FOR THE PRODUCE OF VERY LIGHTWEIGHT CONCRETE, FOCUSES PRIMARILY ON FOAM GLASS AGGREGATES. THERE ARE ALSO MENTIONED OTHERS LIGHTWEIGHT AGREGATES, WHICH WE ARE USE FOR PRODUCE O VERY LIGHTWEIGHT CONCRETE. THEN THERE ARE RISKS UNITED WITH VERY LIGHTWEIGHT CONCRETE. IN THE PRACTICAL PART IS THE PROPERTY ANALLYSIS OF FOAM GLASS AGGREGATES, DESIGN RECIPE VERY LIGHTWEIGHT CONCRETE AND MONITORED MECHANICAL A THERMAL PROPERTIES OF THESE CONCRETE.
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