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Study of alkali-silica reaction in hybrid systems
Bradová, Lada ; Bílek, Vlastimil (referee) ; Kalina, Lukáš (advisor)
This study evaluates question of alkali–silica reaction (ASR) in hybrid system, which was designed in the bachelor's thesis, to meet the requirements of EN 197-1 and classified to the Blastfurnace CEM III/C cements. The durability of this system is a great unknown. For this reason, the same methods (ASTM C1260, ASTM C289 and ASTM C856) were used to observer the ASR effects as the ones used to observer the Portland cement based concrete. Supplementary methods include determination of compressive strengths according to EN 196-2 and scanning electron microscopy to observe the microstructure. Hybrid system results were compared to two different types of cements, CEM I and CEM III/B. From the results of the ASR evaluation assays, it was found that the hybrid system (CEM III/C-HB) and CEM III/B showed the lowest tendency to ASR. The results of the supplementary methods showed that CEM III/C-HB compressive strength increases after 14 days within NaOH by 43 % in comparison to 28 days strength. Based on those results, it is sure that the CEM III/C-HB shows little susceptibility to ASR.
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Effect of cement by-pass dust on properties alkali-activated slag
Janíčková, Vlasta ; Kalina, Lukáš (referee) ; Bílek, Vlastimil (advisor)
This masters thesis deals with influence of cement bypass kiln dust on physico-mechanical properties of alkali activated slag and influence of chosen compounds of cement bypass kiln dust on alkali activated slag. Using alkali activated slag is limited by its shrinkage. The setting time with different amount of cement bypass kiln dust and its chosen compounds (CaO, KCl and K2SO4) were measured by isotermal and isoperibolic calorimetry too. The strength and length changes of the mixtures with different amount of cement bypass kiln dust were measured. Samples were analysed by X-Ray diffraction analysis and scanning electron microscopy. It has been found that the increasing addition of dust reduce setting time, flexural and compresive strength and shrinkage. Presence of free CaO was found being one of the reasons for accelerated setting. KCl and K2SO4 have retarding effect but influece of free CaO prevails even for its lower contents. Long-term properties evolution is strongly dependent on curing regime due to potential volume expansion.
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Methods of using cement kiln by-pass dust in building materials technology
Sikorová, Věra ; Koplík, Jan (referee) ; Kalina, Lukáš (advisor)
This diploma thesis is focused on methods of using cement kiln by-pass dust in building materials technology. By-pass dust was treated to remove chlorides and could then be used as other constituent to various types of cements in the amount of 0–5 wt. % according to ČSN EN 197-1. The properties of dusts before and after chloride removal were examined and after incorporating modified by-pass dust into the cement, the properties of fresh and hardened cement pastes and mortars were studied. It was found that modified by-pass dust after incorporation into cement fulfill requirements of ČSN EN 197-1.
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The influence of alkali activator on immobilization of metals in alkali activated blast furnace slag
Bystrianska, Emília ; Kalina, Lukáš (referee) ; Koplík, Jan (advisor)
In this work the influence of alkaline activator on immobilization of lead and copper in alkali-activated blast furnace slag was investigated. A total of five activators were used; sodium water glass, potassium water glass, sodium hydroxide, potassium hydroxide and sodium carbonate. The leaching test according to ČSN EN 12457-4 was used to evaluate the level of immobilization of heavy metals, the leached solutions were analyzed by ICP-OES. For a better understanding of immobilization, the selected samples were characterized by analytical methods (FTIR, XRD, SEM, XPS). It was found that the degree of immobilization Pb2+ and Cu2+ in AAS was very high, regardless of the type of alkaline activator used.
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Methodology for determining the chemical composition of water glasses
Flídrová, Michaela ; Bartoníčková, Eva (referee) ; Kalina, Lukáš (advisor)
The bachelor thesis deals with the methodology of determination of the chemical composition of water glasses. The aim was to find a more suitable method than the colorimetric analysis used by one of the domestic water glass manufacturers. The current procedure can be used to determine the content of Me2O (Na2O, K2O, Li2O), however, in the determination of SiO2 the method is inaccurate since the color change of the indicator during the second titration is very slow and therefore the equivalence point is ambiguous. The main aim of this work was to find a suitable method for the complex determination of the chemical composition of water glasses, which is compared with other methods used in the analytical chemistry of silicate materials. A very promising method is the conductometric titration with a volumetric hydrochloric acid solution, which provides an accurate, fast and instrumentally inexpensive method of chemical determination.
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Effect of selected activators on the properties of alkali-activated composites reinforced with basalt fibers
Švardala, Daniel ; Hrubý, Petr (referee) ; Kalina, Lukáš (advisor)
This paper deals with the alkali activated materials (AAM) applicable as a construction material, thanks to low cost, environmental friendliness and good mechanical properties. The goal of this thesis is to search for suitable alkaline activator with respect to the final properties of alkali activated composite reinforced with basalt fibers. This thesis is focused on the determination the effect of basalt fibers addition on the mechanical properties. The influence of alkaline activator to basalt reinforcement was determined by simply strength tests, like the compressive and flexural strength measurements. The matrix fiber interaction, as one of the main parameters indicating the quality of the material reinforcement, was measured by electron scanning microscope equipped with an X ray energy dispersing analyzer (SEM EDS). It was found out that the most significant effect on the improvement of the mechanical properties of alkali activated material was in the case of the samples activated by sodium and lithium waterglass. The mechanical strength of these reinforced materials was considerably higher compared to non reinforced samples. AAM activated by potassium waterglass with and without the basalt reinforcement indicates the same or very similar mechanical strength. The comparison of composites with different alkaline activator leads to the conclusion that the mechanical properties depend on the type of used waterglass. AAM activated by sodium waterglass achieve the highest strengths compared to potassium and lithium waterglass activated materials and therefore seems to be the most appropriate for basalt fiber composites preparation.
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Possibilities of Chloride Ions Binding in Alkali-Activated Slag Systems
Chadima, Jan ; Kalina, Lukáš (referee) ; Bílek, Vlastimil (advisor)
This bachelor thesis deals with chloride binding in alkali activated slag and tries to bind chlorides by adding metakaolin, alumina and cement bypass kiln dust to form Friedel’s salt in alkali activated system. These admixtures were selected as a potential sources of aluminate ions that are necessary for the formation of this salt. The amount of chlorides in solid samples and in leachates was determined by Volhard titration. To find out phase composition X-ray diffraction and thermogravimetric and differential thermal analysis were used. Chloride ions were bound in by far the greatest extent in the pastes containing cement bypass dust because only in this case Friedel’s salt was formed. In the case of alumina and metakaolin chlorides were bound likely via adsorption on C-S-H phase.
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Education as a Way to Freedom in Philosophy of Jan Patočka
Kalina, Lukáš ; Pelcová, Naděžda (advisor) ; Rybák, David (referee)
TITLE: Education as a Way to Freedom in Philosophy of Jan Patočka AUTHOR: Bc. Lukáš Kalina DEPARTMENT: Social Sciences and Philosophy Department SUPERVISOR: doc. PhDr. Naděžda Pelcová, CSc. ABSTRACT: This master's thesis will show the concept of education as the way to freedom in the philosophy of Jan Patočka. It will deal with common phenomenological basis of philosopher to education for freedom and the concept of freedom, and also philosopher's viewpoint to the instrumental education and general link between instrumentality and free human beings. What means ''to raise/educate'' or ''to be raised/educated'' and how Jan Patočka thinks in the meaning of educational/raising methods. KEYWORDS: Upbringing, Freedom, Phenomenology, Three Movements of Human Life, Shake, Truth, Patočka
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Hybrid systems based on alkali activated materials and Portland cement
Bradová, Lada ; Koplík, Jan (referee) ; Kalina, Lukáš (advisor)
The most promising route to improve the sustainability of cement is to produce the blended Portland cements with supplementary cementitious materials. Blast furnace slag (BFS) is one of the significant pozzolan source used worldwide in blended cements contributing to lowering of the environmental impact of cement industry. On the other hand, the replacement of the Portland clinker is connected with the undesirable effects such as reduction of early strength development. In order to overcome this disadvantage, the study deals with the development of hybrid cements in which the utilization of solid waste alkaline activator quickly awakens the pozzolanic properties of BFS. The new types of blended alkali activated cements were designed to meet the European standard EN 197 1 and classified to the Blastfurnace CEM III/C cements in accordance with the mechanical, physical, chemical and durability requirements. The effect of alkali activation caused an increase in early (2 days) compressive strength development in comparison with reference sample. The setting time was delayed two times which is also interesting from the point of view of concrete production. Moreover, this non traditional hybrid alkali activated Portland cement provides considerable ecologically and economically potential.
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Leachability of Cu, Ni and Co from alkali-activated matrices
Janíčková, Vlasta ; Kalina, Lukáš (referee) ; Koplík, Jan (advisor)
The work deals with the determination and comparison of leaching of heavy metals from two types of alkali activated systems based on blast furnace slag and high-temperature fly ash. These systems are capable in their structure encapsulate heavy metals, toxic substances or radioactive substances, which can be harmful for the environment. The aim of this work is to prepare a mixture with acceptable mechanical properties. Leachibility from matrix was tested according to ČSN EN 12457–4, followed by analyses Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). Structure of matrix was analysed using Scanning electron microscope (SEM).
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