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Study of stabilization of belite polymorphs
Mudroch, Ladislav ; Dvořák, Karel (referee) ; Gazdič, Dominik (advisor)
This bachelor thesis is focused on the study of the mineralogical composition of cement with a closer focus on belite, its polymorphism, production possibilities and stabilization. The theoretical part describes the composition of cement, its minerals and their properties. Furthermore, the possibilities of stabilization of various polymorphs of belite and their description are presented in this section. The practical part is a summary of the results achieved so far in the research at FAST VUT, THD. Based on this research, an experimental part was designed to verify the hypothesis of the effect of isothermal residence time on belite grain size and its mineralogical composition.
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Study of processes taking place during carbonation of ladle furnace slag
Sadílek, Lukáš ; Cába, Vladislav (referee) ; Másilko, Jiří (advisor)
This bachelor’s thesis is focused on the study of processes taking place during carbonation of ladle furnace slag (LFS). The main phases of the LFS, meaning -C2S, -C2S, C4AF, C12A7 and additionally -C2S were first synthesized in a pure form. Then all the samples, including the LFS, were studied for hydration and carbonation activity. The highest hydration activity was observed in the aluminate phases C4AF, C12A7 and the highest carbonation activity was exhibited mainly by -C2S then also -C2S and LFS. Main products forming during the carbonation are carbonates, meaning CaCO3 in various modifications but also a smaller amount of aluminate phase hydration products formed in a very quick reaction with mixing water. Both temperature and relative humidity have a significant influence on the carbonation process. These conditions affect the carbonation rate itself and relative humidity also changes the ratio of forming CaCO3 modifications, which is most likely due to the changes in the carbonation mechanism.
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Combined Effect of Li, Cu and S Doping on Structure and Hydration of β Dicalcium Silicate
Sedlačík, Martin ; Bartoníčková, Eva ; Novotný, Radoslav ; Palovčík, Jakub ; Másilko, Jiří ; Staněk, Theodor ; Rybová, Alexandra
This study investigates the effect of Li, Cu and S on the structure and hydration of the beta modification of dicalcium silicate (β-C₂S). The doped β-C2S phase was prepared by burning beta-C2S with dopant sources. The structure of prepared β-C2S samples was examined using X-ray diffraction, scanning electron microscopy and infrared spectroscopy. Heat evolution during hydration was assessed by isothermal calorimetry. A positive effect on cement hydration was observed for several dopant combinations.
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Studying Formation and Kinetics of Belite Clinker Hydration
Halešová, Adéla ; Walter, Martin (referee) ; Gazdič, Dominik (advisor)
DIPLOMA THESIS IS DEVOTED TO THE STUDY OF PREPARATION OF PURE BELITE CLINKER FOR THE POTENTIAL INCREASE OF KINETICS OF THE HYDRATION PROCESS BY CHEMICAL ACTIVATION. THE THESIS OF THIS WORK IS BASED ON RESEARCH FINDINGS CONCERNING BELITE CLINKER AND RESEARCH AT THE INSTITUTE OF THD. THE THESIS AIMS TO DESIGN COMPOSITION OF THE RAW MEAL BURNING BELITE, FOLLOWING MODIFICATION BY SULPHATE AND POTASSIUM CARBONATE IN ORDER TO POTENTIALLY INCREASE THE REACTIVITY OF THE BURNT BELITE CLINKER AND THE LABORATORY FIRING OF PREPARED SAMPLES. THE LAST STEP WAS TO ASSESS THE MINERALOGICAL COMPOSITION OF BURNED SAMPLES XRD ANALYSIS AND FOLLOWING COMPARISON CELL PARAMETER OF BELITE WITH AND WITHOUT ADDED MODIFYING ADDITIVES.
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Polymorphism of dicalcium silicate
Matysík, Robert ; Fridrichová, Marcela (referee) ; Gazdič, Dominik (advisor)
The presented bachelor thesis is focused on the study of the mineral belite, polymorphism of belite, its conditions of origin and stability of polymorphs. The theoretical part is focused on the composition of cement, its minerals, modifications and properties. Furthermore, the possibilities of stabilization of polymorphs, synthesis and microstructure of dicalcium silicate are presented in the given section. The practical part is a summary of current research results at FAST BUT, THD. Based on previous work, a research was proposed in which a change in the properties of dicalcium silicate from a pre-fired mixture was observed.
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Preparation and Properties of Belite Clinker
Havlík, Leoš ; Kalivoda,, Karel (referee) ; Gazdič, Dominik (advisor)
DIPLOMA THESIS IS FOCUSED ON THE PREPARATION AND PROPERTIE OF BELITE CLINKER. IT IS BASED ON THE STUDY OF SCIENTIFIC ARTICLES DEALING WITH THE ABOVE MENTIONED TOPIC AS WELL AS THE ANALYSIS OF THE BRNO THD INSTITUTE´S RESEARCH RESULTS. AS PART OF MY EXPERIMENTAL WORK, A PROPOSAL OF THE COMPOSITION OF RAW MEAL TO EXTRACT BELITE CLINKER IN THE PRESENCE OF POTASSIUMS CARBONATE AND SULPHATE WAS MADE TO MODIFY RAW MEAL. THE PURPOSE OF MODIFYING RAW MEAL IS A POTENTIAL INCREASE IN BELITE CLINKER REACTIVITY. FURTHER THE EXTRACTION OF BYPASS DUST FROM A LOCAL CEMENT PLANT WAS CONDUCTED. THE EVALUATION OF THIS RESEARCH WAS MADE BY THE X-RAY DIFFRACTION (XRD) ANALYSIS METHOD.
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Application of Sol-Gel Method for Preparation of Dicalcium Silicate and its Solid Solutions
Baráček, Jan ; Živica, Vladimír (referee) ; Rovnaníková, Markéta (referee) ; Palou, Martin (advisor)
The subject of this doctoral thesis was to elucidate the mechanism of reaction leading to the formation of dicalcium silicate (C2S), its solid solutions and other phosphatic calcium silicate phases using the sol-gel method of synthesis. SiO2 (Tosil A), CaO (calcium nitrate tetra-hydrate) and H3PO4 (as a source of P2O5) were used as starting materials. Series of samples with different content of P2O5 were synthesized. The characterization of Tosil A and samples was based on the following methods: DTA/TGA and EGA, XRD and SEM and EDS analy-ses. It is known, that phosphorous oxide can enter the structure of C2S and possibly form solid solutions and different phosphatic calcium silicate phases in C2S–C3P system. Depending on the P2O5 concentration in mixtures, three distinct phases are formed: larnite (2CaO•SiO2), Ca14,92(PO4)2,35(SiO4)5,65 and 5CaO•SiO2•P2O5, as detected by XRD. Local microanalysis de-monstrated the presence of calcium phosphate epicenters (C3P) containing SiO2, calcium sili-cate (C2S) zones with minimum content of P2O5 and intermediary areas of various phosphatic calcium silicates. The formation of two distinct islets of C2S and C3P is due the affinity of acid oxides (SiO2, P2O5) towards the basic one (CaO) during the sol-gel process. Then, the formation of various phosphatic calcium silicates results from the diffusion of P2O5 and SiO2 towards calcium silicate and calcium phosphate, respectively.
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Study of an alternative binder based on the carbonation of ladle funace slag
Mikulová, Mária ; Koplík, Jan (referee) ; Másilko, Jiří (advisor)
This master’s thesis is focused on the investigation of the chemical processes during the carbonation of a ladle furnace slag (LFSU) and on the investigation of the long-term development of the composition and selected properties of carbonated compacts of LFSU. The main mineralogical phases of the LFSU, -dicalcium silicate (-C2S) and -dicalcium silicate (-C2S), were synthetised for the study. The carbonation reactivity of these phases was examined by perfusion calorimetry. A significantly higher reactivity with CO2 for -C2S was observed. The development of compressive strength, changes in weight and length, and changes in phase composition of carbonated compacts of LFSU in four different environments (distilled water, room temperature; 100% relative humidity, room temperature; 60% relative humidity, 25 °C; exterior) during one year after carbonation were studied. A tendency of compressive strength increase in the first six months after carbonation and a decrease in compressive strength after one year from carbonation was observed in all environments. The long-term increase in compressive strength was mainly caused by hydration of -C2S and mayenite. The decrease in compressive strength after one year could have been caused by hydration of MgO to Mg(OH)2. This, however, was not clearly proved.
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Polymorphism of dicalcium silicate
Matysík, Robert ; Fridrichová, Marcela (referee) ; Gazdič, Dominik (advisor)
The presented bachelor thesis is focused on the study of the mineral belite, polymorphism of belite, its conditions of origin and stability of polymorphs. The theoretical part is focused on the composition of cement, its minerals, modifications and properties. Furthermore, the possibilities of stabilization of polymorphs, synthesis and microstructure of dicalcium silicate are presented in the given section. The practical part is a summary of current research results at FAST BUT, THD. Based on previous work, a research was proposed in which a change in the properties of dicalcium silicate from a pre-fired mixture was observed.
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Preparation and Properties of Belite Clinker
Havlík, Leoš ; Kalivoda,, Karel (referee) ; Gazdič, Dominik (advisor)
DIPLOMA THESIS IS FOCUSED ON THE PREPARATION AND PROPERTIE OF BELITE CLINKER. IT IS BASED ON THE STUDY OF SCIENTIFIC ARTICLES DEALING WITH THE ABOVE MENTIONED TOPIC AS WELL AS THE ANALYSIS OF THE BRNO THD INSTITUTE´S RESEARCH RESULTS. AS PART OF MY EXPERIMENTAL WORK, A PROPOSAL OF THE COMPOSITION OF RAW MEAL TO EXTRACT BELITE CLINKER IN THE PRESENCE OF POTASSIUMS CARBONATE AND SULPHATE WAS MADE TO MODIFY RAW MEAL. THE PURPOSE OF MODIFYING RAW MEAL IS A POTENTIAL INCREASE IN BELITE CLINKER REACTIVITY. FURTHER THE EXTRACTION OF BYPASS DUST FROM A LOCAL CEMENT PLANT WAS CONDUCTED. THE EVALUATION OF THIS RESEARCH WAS MADE BY THE X-RAY DIFFRACTION (XRD) ANALYSIS METHOD.
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