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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.
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Activation of high ash addition of fly ash for concrete production fluid
Ťažký, Martin ; Hela,, Vlastimil (referee) ; Hela, Rudolf (advisor)
Secondary energy products are used in the construction industry for a long time. More strict environmental limits for emissions to air have created new technologies combustion of materials in thermal power plants. In this way combustion are produced a new secondary energy products. It is an attempt to find of suitable use for these products. Their use will have ecological impact on the environment and it will allow prepare of new compositions of higher utility properties. The aim of this study was to develop a new mixture, using the new secondary energy products, for production concrete with high utility properties.
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Study of the properties of concrete with reinforcement, intended for the production of concrete egg-shaped tubes
Šťastný, Antonín ; Hela,, Vlastimil (referee) ; Hubáček, Adam (advisor)
This diploma thesis examines the properties of concrete with reinforcement, designed for the production of a concrete egg-shaped tubes . The stress is put on using various types of fiber reinforcements. Theoretical part is divided into 4 subsections. The topic of the first subsection is a concrete in general. Second subsection deals with various technology of production of concrete pipes. The third subsection is focused on description and summary of basic properties of concrete and reinforced concrete tubes. The last subsection deals with standardized procedures for testing concrete. Experimental part of this thesis is divided into two subsection. First subsection deals with design of a reference sample. Six different samples of a concrete were designed and their rheological properties were tested. Second subsection deals with the additi-on of various types of fiber reinforcement to the reference sample. Eight different admixtures of a concrete were added to the reference sample. Properties of these admixtures were tested in fresh and hardened state.
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The Issue of testing shotcrete
Škapová, Pavla ; Hela,, Vlastimil (referee) ; Hubáček, Adam (advisor)
The master‘s thesis focuses on testing the shotcrete prepared in laboratory conditions. The main observed properties are compresive strenght of shotcrete and modulus of elasticity. The aim is assessment of methods for measuring those parameters. The calibrating correlations for strenght characteristics of shotcrete are given by obtaining the results of used methods. The shotcrete composition, amount and type of accelerating additive as well as economic aspect of using shotcrete is also assessed.
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Verification of durability of ash concrete in the environment XF
Kušiak, Petr ; Hela,, Vlastimil (referee) ; Hela, Rudolf (advisor)
Fly ash is now much used as an admixture to concrete. This master´s thesis focuses on the use of fly ash as an active admixture in concrete environment for XF. The thesis has two parts. The first part collected theoretical information about the origin and behavior of fly ash in fresh and hardened concrete. In the second part was experimental verification of these characteristics. The purpouse of this thesis is to demonstrate that the fly ash attribute to meet all environmental XF.
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The development of self-compacting concrete with fast runs of strength and elasticity modulus
Skřivánek, Michal ; Hela,, Vlastimil (referee) ; Hela, Rudolf (advisor)
My bachelor thesis is about a development of self-compacting concrete. The main advantage of this method is a shorter duration of producing strength concrete and also modulus of elasticity. My analysis consists of describing self-compacting concrete properties, methods for speeding up the process of building strength concrete from less effective heating to using advanced concrete admixtures. Further, an important chapter about influence of concrete mixture composition on modulus of elasticity measurements and in-depth analysis of the SCC mixture composition. Theoretical part is ended by a summary of SCC properties in a fresh or hardened state – all experiment specifics are included. In order to deliver a shorter duration of producing strength concrete and modulus of elasticity in early stages of curing, every SCC mixture mentioned in practical part have been carefully created based on achieved theoretical knowledge with a goal to minimize the impact on rheology of concrete mixture.
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Study of the development, trends and innovations in shotcrete technology
Záruba, Jiří ; Hela, Vlastimil (referee) ; Hubáček, Adam (advisor)
The Bachelor thesis is focused on the study of development, trends and innovations in shotcrete technology. The main target of this thesis is to summarize new procedures in shotcrete technology. Secondary targets include a description of basic properties of sprayed concrete, introducing new trends and technology in recent years. The next sub-goal is to propose experiment that will try new ways of testing shotcrete. Based on these secondary targets is possible to evaluate the current situation in shotcrete technology and fulfil the main objective of this thesis.
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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.
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