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The admixtures which are influencing setting time of portland cement
Hlaváček, Jaroslav ; Kalina, Lukáš (referee) ; Opravil, Tomáš (advisor)
During the production of concrete is important the careful selection of raw materials. Nowadays, we are trying in the production to minimize the economic burden and to maximize the use of secondary raw materials. This work is focused on the use of secondary raw materials from the energy industry in construction for the preparation of hydraulic binders. As the main raw materials were used different power plant fly ash from fluidized combustion. The composition of these secondary materials is quite different from conventional high-temperature ash, due to mixing with water they solidify and harden. Experiments were performed with three lodge fly ash from electrostatic precipitators of the fluidized combustion and one high-temperature fly ash. This work is focused on the possibility of monitoring the use of these secondary materials in construction, especially when tests were evaluated characteristics of strength and speed of setting and hardening.
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Possibilities of clay plasters shrinkage elimination
Melichar, Jindřich ; Koplík, Jan (referee) ; Opravil, Tomáš (advisor)
Earth plasters which are applicated in interiers don´t have just an estetic, but mainly heat storage function. To accomplish better storage properties the plaster has to be laid on the wall in sufficient thick ply. But this use to be accompained by creating of cracks during dehydration of the plaster. This bachelor work will be considering possibilities of elliminating this negative event by additing suitable components to suppress shrinkage and cracks by creating ettringite.
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Volume changes of concrete based on reactive powder components and possibilities of their regulation with chemical admixtures
Hlaváček, Jaroslav ; Kalinová, Helena (referee) ; Opravil, Tomáš (advisor)
Very high strength of RPC allows them to an unusual extreme possibilities of their applications. Volume change (shrinkage) negatively affects their relatively broad range of applications, particularly in applications which are used for filling tubes or other components. In today's advanced time with plenty of chemical ingredients and additives on the market (such as the expansion component) could be a side effect of this largely eliminated, or removed entirely. Only some components of the expansion will be appropriate for RPC cements. This reaserch investigates the expansion of ingredients on the basis of sulfates and monitors not only volume changes, but also the strength characteristics and tolerability of the tested anchors tested with a matrix component of the expansion.
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Supersulphates cements
Mohelská, Lucie ; Wirthová, Michaela (referee) ; Opravil, Tomáš (advisor)
The work is studying posibilities of use secondary materials produced by energetical industry. In fact it studies posibilities of preparing supersulphates cements with secondary raw materials. Its main system for simulation was used milled portland clinker. To clinker were added diferent secondary raw materials from energetical industry with sulphate. On prepared samples were watched mechanical properties in time. Tested were different samples of secondary raw materials.
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Gypsum free cements with retarded setting by plastisizer and alkali compond
Sedlařík, Tomáš ; Ptáček, Petr (referee) ; Havlica, Jaromír (advisor)
This thesis deals with preparation of gypsum free cements with retarded solidification. It focuses on their preparation by alkali activation with addition of superplasticizers and without superplasticizers. The main aim of this work is to suggest substitution of gypsum in Portland cement by other materials. Ash after fluidized combustion was chosen as a good compensatory raw material with respect to sustainable development. Milled fluidized bed ash from heating station Třinec was tested. Examined pastes were prepared by alkali activation. 50% solution NaOH and sodium water-glass were used as alkali activators. Trial specimens (20x20x100 mm) were prepared from pastes. Measurements of calorimetric properties of unprocessed pastes tested mixtures were implemented. Bending and compressive strength of pastes were also explored.
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The database of waste incinerators in Europe
Šaldová, Lenka ; Ručka,, Jan (referee) ; Hluštík, Petr (advisor)
The aim of this thesis is to describe modern technological processing lines MSW incinerators. Describe individual objects and their links with the principle of thermal combustion. Processes described in the process line will be: waste reception, storage and waste materials, waste pretreatment, loading of waste into the process, thermal treatment of waste, energy utilization and conversion, gas cleaning, disposal of residues from flue gas cleaning, gas discharge, monitoring and control emissions , cleaning and inspection of wastewater treatment and disposal of ash (kiln ash), discharge (disposal) of solid residues. In the second part of this database will be set up incinerators occurring in Europe with basic information (address, website, kiln type, number of lines, the amount of waste incinerated, etc.). The developed database will be created graphs for better clarity and comparison. The database will be accompanied by the emission requirements of individual countries according to the applicable domestic and European legislation.
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Possibilities of Cellular Concrete Utility Properties Improvement for Low-Energy Buildings
Neubauerová, Alena ; Ing.Oldřich Dobrý, CSc. (referee) ; Kulísek, Karel (advisor)
Aerated concrete is a modern construction material with excellent thermal – insulation properties with possibility of a fast construction of the building. Moreover we can use secondary raw materials such as fly ash and gypsum during production of aerated concrete, so we save our environment. At present we are trying to save funds for heating the house, so we are looking for suitables materials to cover the requirements for low energy housing. But low – energy buildings wouldn´t be enough for the future. It´s possible now to build passive houses and zero houses, that´s why advances are necessary in improvement of utility properties of building materials, aerated concrete in our case.
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Development of different types of fly ash autoclaved aerated concrete
Bednárik, Vít ; Kulísek,, Karel (referee) ; Drochytka, Rostislav (advisor)
This bachelor´s thesis deals with the current technologies of production and raw materials used in the production of fly ash autoclaved aerated concrete. The choice of suitable materials is an important prerequisite for achieving the desired properties of the finished product. Fly ash autoclaved aerated concrete has become one of the options, how to use fly ash, produced as a secondary raw material in the combustion of coal in heating power plants. This work deals with the comparison the physico - chemical properties of the fly ash in the Czech Republic and the subsequent optimization of the composition of the raw mix for the production of fly ash autoclaved aerated concrete with the maximum use of alternative raw materials.
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