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Study of fibres behaviour in cement composite
Nešporová, Tereza ; Křížová, Klára (referee) ; Sedlmajer, Martin (advisor)
Bachelor thesis is focused on behavior of fibers on selected properties of fine–grained cementitious composite in fresh and hardened state. The emphasis is on usage of enviromentaly friendly fibers, specifically fibers obtained from recycled materials. Different fibres in cement composites are compared in terms of geometry and material base. The findings at the theoretical level are summarised, including information from scientific studies. Practical determination of selected properties on fresh composite such as consistency and shrinkage of the material is covered. Mechanical properties such as flexural tensile strength and compressive strength are also determined. The water permeability is also investigated.
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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.
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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.
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Economic aspects of environmental use of building materials based on secondary raw materials.
Ťažký, Tomáš ; Durica,, Tibor (referee) ; Sedlmajer, Martin (referee) ; Nosek,, Karel (referee) ; Kulísek, Karel (advisor)
The disses thesis is focused on usage of secondary raw materials from the electric power industry, specifically fly ash as a component for the building industry, concentrated on concrete. Two main streams are covered, environmental and economical. Reasons, which led to focus on the selected subject are coming mainly from the scarcity and availability of high-quality mineral resources, environmental pressure for usage of industry byproduct, reducing emissions and economical pressure to reduce production cost, especially raw materials. The main purpose of the work was to verify the possibility of increasing the usability of fly ash as a mineral additive in the technology of concrete production with materials retrieved from coal fired power plants and applying mechanical activation of fly ash. The main goal of the experimental part of work was to demonstrate improvement of fresh and hardened concrete properties as a main condition to support economic efficiency of mechanical activated fly ash. Base on previous facts the methodology was covering two main areas, the experimental and the assessment. Relatively large sets of tests were performed, using a wide range of tested high temperature fly ash and fluidized bed combustion fly ash granulometrically treated, by mixing and grinding. Results of the testing confirmed focused parameters for concrete and mortar mechanical properties, total economical efficiency of the targeted solution and the subject of the dissertation. In the experiment section has been retrieved valuable findings contributing to the overall knowledge of the faculty, also for the practical application. The results of the tests confirmed the achievement of the planned target parameters, both in terms of physical and mechanical properties of experienced mortars and concretes, as well as the overall economic efficiency of the proposed design and the topic of the disses thesis. Within the experimental work, valuable professional knowledge and benefits w
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Issues of experimental determination of concrete moisture
Vaněk, Dominik ; Přikryl, Jan (referee) ; Sedlmajer, Martin (advisor)
This bachelor´s thesis studies issues of moisture determination in concrete. First part describes the relationship between moisture and concrete structure. Second part is dedicated to methodology of concrete moisture determination and also to an own experiment. Main focus of thesis is to evaluate the accuracy and relevance of selected methods of determining the concrete moisture.
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Possibilities of using light artificial aggregate based on sintered high-temperature fly ash in heat-resistant concrete structures
Mazán, Tomáš ; Sedlmajer, Martin (referee) ; Křížová, Klára (advisor)
The final thesis describes contemporary knowledge of research and development in the area of the heat-resistant concrete constructions with using porous aggregate from flying ash. The theoretical part introduces the production and the agloporit aggregate basic features. The principles of using in the incoming materials of light weight concrete are presented next. The thermal loading with influence at concrete constructions and the other individual materials is also mentioned in the final thesis. The experimental part of the thesis deals with the impact of lightweight aggregate quantity on the high temperature resistance. Conclusion pays attention to the obtained results evaluation and to the composition an optimal formula LWAC, which could be able to resist short-term thermal loading.
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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.
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Development of lightweight composites based on foam glass aggregate
Szotkowská, Michaela ; Sedlmajer, Martin (referee) ; Zach, Jiří (advisor)
Bachelor´s thesis is concerned of development of bonding foam glass with organic binders. The theoretical part describes the use of recycled glass to produce aggregates based on foam glass. It also describes its production, properties and use in construction. The work also focuses on the types of organic binders and their properties. In the practical part, the optimal ratio between the binder and the filler is proposed and the subsequent assessment of the required properties of the final composite.
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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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