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Properties of alkai-activated aluminosilicates subjected to high temperatures
Halasová, Kristýna ; Bayer, Patrik (referee) ; Rovnaník, Pavel (advisor)
Currently the concept of geopolymer or alkali activated aluminosilicate is very mentioned topic. Many studies concerning utilization of these materials have already been made, but if we want to use these materials in building industry in the future, further research will be needed. This thesis deals with the influence of high temperatures on alkali-activated slag, fly ash and metakaolin-based composites. The work compares mechanical and technological properties, microstructural changes and effect off iller on the geopolymer composites heated at 200–1200 °C. In conclusion, the individual properties are compared and application possibilities of these materials are evaluated.
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Optimization of concrete mixture based on alkali activation of secondary materials
Šafář, Martin ; Šoukal, František (referee) ; Kalina, Lukáš (advisor)
This bachelor thesis deals with design, preparation and optimization of concrete mixture based on alkali activated secondary materials – blast furnace slag and fly ash. Sodium hydroxide partially replaced by bypass cement kiln dust was used as an activator. Mixture design was based on model made for Portland cement based concrete. Observed properties were workability of fresh mortar, price of mixtures and mechanical properties of concrete. Microstructure and composition of concrete was studied by SEM-EDX and XRD. Analysis of raw materials was based on XRF. The optimal mixture composition was chosen from obtained data.
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Elemental composition analysis of inorganic materials
Szmek, Václav ; Richtera, Lukáš (referee) ; Zmrzlý, Martin (advisor)
This work deals with elemental analysis of inorganic materials, that are presented by blast furnace slag and geopolymeric material containing fly-ashes. In the theoretical part there are explained principles of elemental analysis of inorganic materials. Ways of dissolution of samples, optical emission spectroscopy and electron microscopy with energy dispersive x-ray analysis are commented. In experimental part the ICP analysis of oxide standards is described. The standards were used for estimation of EDS-correction factors. Then follow the preparation, proving and use of standards in analysis of blast furnace slag. The work is finished by exact analysis of concentration profiles of elements in interface of phases in geopolymeric material.
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Carbon nanotubes in building materials
Fialová, Barbora ; Bayer, Patrik (referee) ; Rovnaník, Pavel (advisor)
Carbon nanotubes (CNTs) has become of great interest for scientists in many disciplines. This study examines the effect of CNTs as nanosized reinforcement for metakaolin–based geopolymer. It was found out that the addition of CNTs considerably affects the compressive and flexural strength geopolymer samples. The influence of CNTs on microstructure was examined using mercury intusion porosimetry and scanning electron microscopy.
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Artificial stone - methods of preparation and properties
Pluskalová, Barbora ; Bayer, Patrik (referee) ; Rovnaník, Pavel (advisor)
The aim of the thesis „Artificial stone – Methods of preparation and it´s properties“ deals with the various methods and issues concerning the preparation of artificial stone. The thesis presents the summary of materials and various methods suitable for the preparation and points out mechanical properties, including durability of material, which serves as an alternative to natural stone. Further on, the thesis deals with the studies of binding systems based on geopolymers, which are used for the artificial stone preparation. This part of the thesis is associated with the experimental part, which is aimed at choosing the suitable mixing ratio of binder to aggregate in the artificial stone based on metakaolin geopolymer. According to the results of mechanical tests and aesthetic impression the author chose the best composition and then created a decorative element.
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Effect of Grain Size of Waste Glass on Properties of Alkali Activated Aluminosilicate Composites
Novák, Václav ; Vyšvařil, Martin (referee) ; Bayer, Patrik (advisor)
The diploma thesis is focused on the use of the waste glass with different fineness on alkali - activated composites, mainly based on slag and fly ash. The theoretical part is focused on materials that are most used for alkaline activation - slag, fly ash and their composites with waste glass. The theoretical part also deals with the alkaline activation of composites from these materials and the factors that influences the microstructure and properties of these composites. In the experimental part were prepared composites from slag and fly ash with a waste glass as substitute. These composites then have been examined on mechanical properties and microstructure, also how different fineness of glass influences these properties. Then it will be decided whether it is economically advantageous grinding waste glass to finer fractions
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Preparation of geopolymeric binders based on power plant fly ashes
Jevická, Lucie ; Opravil, Tomáš (referee) ; Šoukal, František (advisor)
This thesis deals with preparation of geopolymeric binders based on power plant fly ashes by alkali activation. It studies influence of different types ashes content in pastes on setting and final properties of geopolymeric binders. The aim of study is determination of optimal ratio of raw materials to reach the best possible characteristics of final binder. Ashes from high-temperature and fluidized bed coal combustion were used for experimental works. Mass content of ashes in tested mixtures and total ratio of oxides crucial for polycondensation and geopolymeric structure formation were chosen as major input parameters. Calorimetric measurements of tested mixtures fresh pastes were implemented to learn about setting process. Hardened binder specimens were tested for bending and compressive strength.
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Fibre coposites with alkali -activated slag matrix
Pluskalová, Barbora ; Bayer, Patrik (referee) ; Rovnaník, Pavel (advisor)
This master thesis is concerns the preparation of Alkali Activated Materials, specifically Alkali Activated Slag (AAS), with the addition of fiber reinforcement. Alkali Activated Materials have great potential for use in construction practice. However, their use is limited by certain undesirable properties, which can be diminished by adding fiber reinforcement. This thesis deals with the influence of carbon fibers (2 % by weight of the binder) and carbon nanotubes (0,2 % by weigh of the binder) on the mechanical properties, microstructure and shrinkage of AAS. The results of the experiments which were carried out correspond with the literary research. Conclusions of this thesis agree with research published in original scientific papers.
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Rehydration of alkali-activated slag after high temperature loading
Fialová, Barbora ; Bayer, Patrik (referee) ; Rovnaník, Pavel (advisor)
Ground granulated blast furnace slag is a by-product of the steel industry and is often used in combination with ordinary Portland cement as a binder in concrete. When concrete is exposed to high temperatures, physical and chemical transformations lead to significant loss of mechanical properties. This study aims to investigate the effect of high temperatures and rehydration on the mechanical properties, microstructure and phase composition of alkali activated slag. The results of the research could make an important contribution to decisions made concerning the reconstruction of structures affected by fire. In suitable cases it would be possible to regenerate parts of a structure instead of totally rebuilding it.
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Synthesis of Aluminosilicate Systems Based on Alkali Activation of Industrial By-Products
Kalina, Lukáš ; Rovnaníková, Pavla (referee) ; Škvára, František (referee) ; Havlica, Jaromír (advisor)
Portland cement-based products are the most commonly used building materials. However, it is well known that the production of OPC not only consumes a significant amount of natural resources and energy but also releases high quantity of carbon dioxide (CO2) to the atmosphere. Purpose of this work is to develop new cementitious material similar to Portland cement-based concrete, which is convenient in terms of energy and is environmental-friendly at once. This work presents preparation, composition and properties of inorganic aluminosilicate polymer, called geopolymer, synthesized from blast furnace slag and fly ash, activated by sodium hydroxide and cement kiln dust. Study of the microstructure was based on SEM-EDX-WDX, TG-DTA-EGA and XRD analysis.
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