|
|
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.
|
|
|
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.
|
|
|
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.
|
|
|
Influence of the type of dispersed reinforcement on selected properties of concrete
Gajdušková, Patricie ; Křížová, Klára (referee) ; Sedlmajer, Martin (advisor)
This thesis is focused on the usage of fibers in concrete. The fibers are dispersed reinforcement which may have different behaviour based on the material characteristics or the geometric shape of the fibers. Due to this, we may predict the appropriate application of fibers and possibly improve mechanical properties of concrete. At the same time, the influence of used fibers on the behaviour of the concrete when exposed to high temperatures, thus the fire resistance of material, is observed. The purpose of this thesis is to compare the properties of the individual fiber types in concrete, which are suitable for specific application of fibre reinforced concrete.
|
|
|
Possibilities of using lightweight aggregate of the foam glass bonded with cement
Jahn, Jeroným ; Křížová, Klára (referee) ; Sedlmajer, Martin (advisor)
In the theoretical part of bachelor thesis are findings about use of lightweight aggregate from foam glass. Part of this work is a description of production , raw materials for production , and especially the properties of aggregates. The work deals possibilities of interconnection and the use of foam glass aggregates in building industy . There is describe a risk of alkali-silica reactions in combination with cement. In the practical part are verified application possibilities and properties of cement composite with lightweight aggregate foam glass .
|
|
|
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.
|
|
|
The possibilities regulation of production hydration heat of concrete with plasticizer
Hermann, Radek ; Halas, Vladimír (referee) ; Sedlmajer, Martin (advisor)
This thesis studies the problematics of water reducing and high range water reducing admixtures and their influence on the process of hydration of cement pastes. The process of hydration is examined in this thesis both in terms of hydration heat and hydration temperature rise. Attention is also paid to the influence of plasticizers in combination with retarding admixture regarding rheological properties of modified fresh cement pastes and their mechanical properties after 3 and 7 days from mixing.
|
|
|
Development of board materials based on secondary raw materials with a good ratio of thermal insulation and mechanical properties
Szotkowská, Michaela ; Sedlmajer, Martin (referee) ; Zach, Jiří (advisor)
This diploma thesis focuses on the development of board materials based on secondary raw materials. The theoretical part outlines secondary raw materials and their further usage. In addition, the theoretical part deals with a description of protective panels with a focus on underlying profiles and requirements for protective panels in terms of thermal protection of buildings. At the end of the theoretical part, a multicriteria analysis and a method of assessing the impact of the products on the environment using LCA / EPD is described. The practical part describes input raw materials from various industries, test samples, their tests, and subsequent evaluation of required properties. Using the multi-criteria analysis, a board material with a favorable ratio between mechanical and thermal insulation properties was selected for the production of the base profile. Furthermore, the practical part deals with the production of the underlying profile, its testing, determining its competitiveness in the market, and a simplified description of its impact on the environment.
|
|
|
Study of the influence organic fibres on the fire resistance of concrete
Klobása, Jan ; Přikryl, Jan (referee) ; Sedlmajer, Martin (advisor)
The master thesis is focused on current issues of concrete behaviour under high temperatures. In the theoretical part, a search of knowledge about changes in concrete, which take place when exposed to thermal loads, which simulates the effect of fire, is performed, and summarized. It is also important to summarize the changes in the individual components that are used to produce concrete. This work describes the effect of high temperatures on mechanical and physical properties as well. There is an information about the most used fibres and their function in concrete. Emphasis is placed on describing the possibility of using recycled PET or cellulose fibres due to the positive environmental impact. In the experimental part, recipes with different types and amounts of fibres are proposed. The subject of the research was to determine how individual types and amounts of fibres affect the physical mechanical properties of concrete and their suitability for use at high temperatures. Microscopic scanning and study of changes in the structure of concrete was also performed.
|
|
|
Current development of UHPC concrete and verification of selected properties
Panenková, Monika ; Sedlmajer, Martin (referee) ; Křížová, Klára (advisor)
This bachelor thesis deals with current developments and research in the field of ultra high performance concrete – UHPC. Theoretical part of this work is focused on the composition and properties of UHPC compared to normal strength concretes. It describes design principles, constructions in the world and also in the Czech Republic and other use of this material. Experimental part describes the design of UHPC, manufacture of test specimens and testing for certain physical and mechanical properties such as compressive strength, tensile strength, bending strength, water impermeability, frost resistance, resistance to chemical de-icing substances and abrasiveness of the material.
|
guest ::
