|
| |
|
|
The development of ultra-high strength (UHPC) and reactive powder (RPC) composites
Rundt, Lukáš ; Hela,, Vlastimil (referee) ; Hela, Rudolf (advisor)
Bachelor’s thesis studies ultra-high strength concrete and reactive powder composites. In theoretical part there are researched and described properties of raw materials used for their production, mainly additions. Design methodology, processing and types of curing are also studied. Psychical mechanic and durability properties of fresh and hardened concrete are described. In practical part 4 mixtures were designed and prepared and their rheological properties, strengths after 7 and 90 days in case of UHPC and strengths after 7, 28 and 60 days in case of RPC were tested.
|
|
|
Activation admixtures in concrete
Eger, Lukáš ; Hela, Vlastimil (referee) ; Hela, Rudolf (advisor)
The aim of my bachelor´s work is the summarization and focus on admixure concrete,and the active and inert admixure, which have some positive characteristies for fresh and hardened concrete. Theoretically, I tried to study the increase of their joining potential while this characteristic can be used by either chemici or mechnical way, their combination as well. I also Works on evaluetion of physically mechanical influence for fresh and hardened concrete that can up to 60 days old while the cement was partly substituted by admixure of different character.
|
|
|
Optimization of the concrete composition with the use of recycled concrete aggregates
Skriňáková, Eva ; Holák, Michal (referee) ; Hela, Rudolf (advisor)
Concrete as a building material is subject to continuous innovation and thanks to advanced technology and quantum of research, its properties are still improved. It is logical that the more concrete we produce, the more waste it arises. The volume of this waste can not be stored in landfills endlessly, nowadays most of the waste economies in the world are trying to recycle concrete rubble. The recycling is not such a problem, the technology has been long verified but the quality of the recycled concrete aggregate is unquestionably one of the primary assumption which leads to accomplish required properties of concrete. In fact, the recycling process is „crushing“ the concrete into particles with an effort to eliminate the cement paste on the surface of the aggregate. An ideal solution would be create a resistant and firm coating that would adhere perfectly to the cement matrix. This diploma thesis is focused on the properties of recycled concrete aggregate and methods of improvement and optimization of the concrete mix composition.
|
|
|
SCC with secondary raw materials
Ťažká, Lucia ; Ťažký, Tomáš (referee) ; Hela, Rudolf (advisor)
Bachelor thesis is focused on the possibility of using secondary raw materials and their application to the production of SCC. Large part deals with impurities of type I and its application results mainly from abroad. Furthermore, this work examines the impact of different types of impurities on the resulting concrete durability in various aggressive environments. The practical part is focused on the use of chemically non-reactive additives of type I instead of the commonly used additives of type II which are used to replace part of cement and the resulting design and manufacture of low-strength SCC using appropriate additives.
|
|
|
The influence of zinc oxide on the cement composite with silica fume.
Dobiáš, Jiří ; Koutný, Ondřej (referee) ; Šiler, Pavel (advisor)
The aim of this work was to investigate the influence of zinc oxide on the properties of blended Portland cement mixed with silica fume. On the pastes were monitored flow properties and by using of isoperibolic calorimetry process of the hydration. On the prepared samples were studied mechanical properties of obtaining values of compressive and flexural strength after 1, 7 and 28 days. By using of XRD were measured phase composition and microstructure development war observed by SEM. The elemental composition of cement leaches was measured by using of ICP-OES.
|
|
|
High-performance concretes based on the secondary raw materials
Sáček, Josef ; Brandštetr, Jiří (referee) ; Šoukal, František (advisor)
This work is devoted to study of physical-mechanical properties and structure of high performance concretes (HPC) based on portland cement. The attention is focused on possibility of substitution of economic high-cost components of concrete with utilization of secondary raw materials or cheaper components. Properties of raw materials and their influence on whole quality of concrete were tracked by various methods. Mechanical properties of prepared HPC samples were tested especially (compression and flexural strength) with further microscopic study of structure. Isoperibolic calorimetry and X-ray powder diffraction method were also used for concrete characterisation. These methods allowed to determine the influence of raw materials on prepared HPC and to carry out a certain optimization among price and quality of this material.
|
|
|
The effect of fly ash aerated concrete production technology to formation of tobermoritic phases
Fleischhacker, Ján ; Kulísek, Karel (referee) ; Drochytka, Rostislav (advisor)
Autoclaved aerated concrete is long-time ecological building material with usefull properties. There needs to be done research of its mineralogical compound for reengineering the production. The main mineral compound of AAC is tobermorite, it increases its mechanical properties. In the presence study, we examine the usage of nature and artificial silicious materials. Also, we investigate the influence of sulfate and alumina admixtures, as well as fluidized bed combustion ash, which can be used as the lime and gypsum replacement. Closure of the study is design of the optimal raw material composition, also hydrothermal treatment of autoclaved aerated concrete. In relation to its mechanical properties, mineralogical composition and cost.
|
|
| |
|
|
Possibilities of using different types of admixtures in shotcrete technology
Berčík, Martin ; Brožovský, Jiří (referee) ; Hubáček, Adam (advisor)
The Bachelor’s thesis is conceived in the form of research findings on current knowledge of inert and active ingredients and their effects on the shotcrete. It focuses mainly on the composition of individual ingredients, their function executing in the concrete mix and explains how they affect the selected physical and mechanical properties. The work enlightes the importance of using co-products from the industry production as an additive to concrete in terms of both ecological and partly economical.
|
guest ::
