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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.
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Possibilities of utilizing lightweight autoclaved silicate based materials for insulation of building structures
Novák, Jakub ; Sedlmajer, Martin (referee) ; Zach, Jiří (advisor)
This bachelor´s thesis deals with the issue of thermal insulation for building structures using autoclaved aerated concrete on silicate based with density up to 200 kg/m3. The theoretical part presents the knowledge of the thermal protection of buildings and thermal insulation materials. Thereafter are distributed insulation systems. Production of aerated concrete and its properties is described in detail. In thesis were evaluated possibilities of use this material. The materiál is proved to be suitable for the production of thermal insulating wall, insulated foundation slabs or composite external panels. In the practical part were find out the values of physical and mechanical properties of aerated concrete product. Test results showed that the product can be used as an alternative to standard insulation systems. Component of the practical part was also to compare various insulation materials on the present market. In the conclusion is performed an overall assessment that includes the overall findings and the results.
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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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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 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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Effect of chemical additives on the process hydration temperature of cement pastes
Knotová, Kateřina ; Halas, Vladimír (referee) ; Sedlmajer, Martin (advisor)
Chemical additives, especially plasticizers and super plasticizers, are necessary components of nearly every concrete. These additives improve the workability of grout and concrete mixes thereby reducing vibration intensity during process of compaction. Advantages of these additives are associated with reduction of the amount of gauging water which leads to decrease water-cement ratio, increase strength and durability of concrete, eventually improve other attributes. The aim of this thesis is to observe the effect of plasticizers and their dosage on the rheology and development of hydration temperatures in simpler systems, which are the cement pastes. The thesis also considers compressive, tensile and flexural strength of concrete.
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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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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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