National Repository of Grey Literature 7 records found  Search took 0.00 seconds. 
The study of sulfate depletion in cement binders
Jurko, Michal ; Švec, Jiří (referee) ; Novotný, Radoslav (advisor)
This bachelor thesis deals with the study of sulfate depletion in cement binders. Basic knowledge about cement binders is summarised at the beginning of the theoretical part. The theoretical part goes on to describe the hydration of Portland cement (PC) and to briefly describe the influence of different types of milling on PC particle size. In the experimental part, PC fractions of various average particle sizes were prepared on a planetary ball mill for wet conditions. On the prepared cement, their hydration was studied using isothermal calorimetry; especially sulfate depletion, portlandite precipitation, heat flow rate and induction period interval. n the thesis were also used analyzes for autogenous shrinkage, XRD and STA. The input raw materials are cement CEM I 42,5 R (grey, Českomoravský cement, a.s. – Mokrá, Czech Republic) and sulfate-resistant cement CEM I 52,5 R (white, Aalborg Portland, a.s. – Aalborg, Denmark). On the basis of the results analysis, a proposal was made to correct the presence of sulfate ions by adding gypsum in these cements. In the case of CEM I 52,5 R the correction is recommended and in the case of CEM I 42,5 R the correction is necessary.
Utilization of fluidized bed combustion solid residues in the production of refractories
Tvrdý, Michal ; Novotný, Radoslav (referee) ; Opravil, Tomáš (advisor)
The thesis deals with the preparation, study and analysis of refractory ceramics, namely fireclay mortars for stove purposes with the addition of fluid ash. The mixtures for preparation of refractory ceramics were doped with different content of fly and bed fluid ash in order to reduce the consumption of the original raw materials for the preparation of these materials. Fired slate clay, refractory clay, fly and bed fluid ash were used for preparation the samples. Input raw materials and fired fireclay mixtures were characterized by XRD, TG-DTA-EGA, TDA, SEM-EDS, heat microscopy, isothermal calorimetry, ICP-OES. The mechanical properties, i.e. compressive strength and tensile bending, were also determined on fired fireclay mortars. The results showed that the properties of the fireclay mortar containing fly ash are comparable to the starting mortar to a specific ash dosage. It has also been found that bed fluid ash is not suitable for the production of refractory materials.
Heat insulating moulded refractory materials
Novotný, Radoslav ; Lang, Karel (referee) ; Raschman,, Pavel (referee) ; Havlica, Jaromír (advisor)
Doctoral thesis is focused on the study, research and development of heat insulating moulded refractory materials. The replacement of shaped instead of unshaped refractories is recently and strongly industrially demanded and belongs to ongoing research topics. With the increasing demand of energy savings, the excellent insulation properties are essential. The insulating properties of castables are the result of targeted porosity formation. The porosity is coming from the controlled air intrusion into material resulted to foamed structure. The foaming process was achieved by mixing of separately prepared aqueous foam into raw castable slurry or by in situ foaming of intensively mixed castable slurry with the surfactant additive. Nevertheless, the study of foam behaviour and the influence of additives on binder hydration and setting processes (i.e. calciumaluminate cement) was substantial for successful preparation of the experimental samples. The two types of the experimental samples were prepared. The first one was based on mixing of kaolin slurry with pre-prepared aqueous foam, whereas the de-aglomeration ability of kaolin specie was utilized to water-particle film formation. In situ foaming of multicomponent system is the second one. The both processes brought some negative attributes, so the optimal properties of prepared castables were achieved by their combination.
Preparation of calcium-aluminate phases
Ohaňka, Zdeněk ; Novotný, Radoslav (referee) ; Koplík, Jan (advisor)
This work focuses on the preparation of calcium aluminates by solid state synthesis and by sol-gel method. Phases prepared were monocalcium aluminate (CA), dodecacalcium heptaaluminate (C12A7), tricalcium aluminate (C3A) and calcium dialuminate (CA2). Two modifications of sol-gel method were used – the difference between them was in the addition of EDTA. Each method was closely described and results were compared according to the achieved purity of prepared phases. X-ray diffraction analysis was used to determine the purity of prepared calcium-aluminates.
Chemical wall clamp based on fast-setting geopolymeric binders
Novotný, Radoslav ; Kalina, Lukáš (referee) ; Šoukal, František (advisor)
The aim of this work is to develope fast-setting geopolymeric binders applicable in the chemical wall clamp. This clamping systems are big trend because of easy application, ability to transfer big forces and short setting time. Binders of this systems are based on polymeric resin. Their raw materials are expensive, toxic and flammable substances. Based on this consideration an anorganic fast-setting geopolymeric binder was developed. This binders consist of mixture of metakaolin and precipitated silica activated by potassium hydroxide. Binder were characterized by suitable analytic methods (XRD, SEM, DTA). The results of this metods were used for optimalization of binder properties.
Setting control of alkali-activated systems
Komosná, Kateřina ; Novotný, Radoslav (referee) ; Kalina, Lukáš (advisor)
This thesis is focused on the possibilities of setting control of alkali-activated systems based on blast furnace slag. The aim of this work is finding the suitable retarder that most extends the time of setting and also preserves the mechanical properties of alkali-activated material. In experimental section were prepared samples of blast furnace slag, water glass, water and additives in various weight addition. Testing samples have undergone of flexural and compressive strength tests. Then the setting time was determined using the Vicat device. The samples were measured calorimetrically because of monitoring the setting process. Finally the mixtures were observed using scanning electron microscope for a closer view on the structure of samples and distribution of setting retarder.
Interaction of Lanthanide trichlorides with the construction materials of a purification apparatus
Novotný, Radoslav ; Zmrzlý, Martin (referee) ; Richtera, Lukáš (advisor)
Lanthanide halides LnX3 are the base material for preparation a different compounds, but also the pure metals. Our faculty is used for the syntesis organometallic catalyst. This compounds are very sensitive to the presence of moisture and oxygen. Lanthanide halides are commercially available in anhydrous or hydrated form. This thesis is devided eight chapters and deals with matherial of the apparatus, which is designed to sublimation of anhydrous lanthanide halides. Initial chapters described the properties and preparation this substances. Following are on the sublimation and corrosion materials. In the last chapter is the skeleton sketch, layout and a availability parts of construction. The aim of this work was to create theoretical basis of construction aparatus and commissioning.

See also: similar author names
1 Novotný, R.
17 Novotný, Radek
2 Novotný, Radimír
1 Novotný, Radovan
5 Novotný, Robert
1 Novotný, Robert Radim
9 Novotný, Roman
5 Novotný, Róbert
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