National Repository of Grey Literature 65 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Natural hydraulic lime and natural cement: a possible solution to more sustainable future of construction binders
Rokosová, Dita ; Přikryl, Richard (advisor) ; Kozlovcev, Petr (referee)
The purpose of this thesis is to address the issue of carbon dioxide emissions in the production of Portland cement. CO2 emissions are generated during the production of this hydraulic binder not only by burning fuels needed for the firing of cement clinker, but primarily during the process called calcination. Alternatives to Portland cement could be Roman cement and/or natural hydraulic lime, which are fired at lower temperatures than Portland cement. Firing at lower temperatures saves fuel needed for firing the raw material mixture, and particularly prevents the mixture from being heated above the sintering temperature. This bachelor's thesis also analyses the use of biomass fuels, solid municipal waste, etc., which are widely used for clinker firing instead of fossil fuels in the Czech Republic. Graphs, based on data from the Czech Cement Industry Association, were created to demonstrate the relationship between the increasing proportion of alternative fuels and the rising consumption of heat required for clinker firing. In the final part of the thesis, three geological areas in the Czech Republic, where a long history of hydraulic binder production continues until the present, are examined. These locations are described, and three rock formations are identified based on previous analyses, which...
Granites of Prague stone arch bridges in 19th c.: sources, properties, and weathering
Rauvolfová, Hana ; Přikryl, Richard (advisor) ; Krutilová, Kateřina (referee)
This thesis deals with the topic of the degradation of granite masonry, which was used for the construction of two stone arch bridges in Prague. Granite is used as a popular building material for its high durability however it is still necessary to check the condition of the masonry, especially in cities where stone is subject to different degradation process than stone in nature is exposed to. The first chapter is devoted to description of granite from a petrographic point of view, its physical and chemical properties and the important properties that makes it a popular building stone. Furthermore, the classification of granitic rocks and important quarries in Czech Republic is described here. The next chapter is dedicated to the description of the degradation process that negatively affect the rock. Degradation processes are divided into three categories: physical, chemical and biodegradation. Degradation processes are described here in general, but the results of tests performed when measuring degradation on granite historical buildings from abroad are also presented here. The last part of this thesis is dedicated to stone arch bridges, their most common faults and repair methods. They focus more on the two Prague bridges from the 19th century, the Legií bridge and the Palacký bridge, for the...
High purity silica materials: genesis, properties, and their potential resources in the Czech Republic
Tichý, Daniel ; Přikryl, Richard (advisor) ; Zachariáš, Jiří (referee)
Quartz and other siliceous materials are among the most widely used industrial raw materials. Demand for high-purity silica increased during past decades, specifically due to its growing use in the photovoltaic energy or electronic/electrical industries. Strict requirements on the purity of the feedstock, together with very complex processing technology, narrow down the choice of potential sources suitable for industrial extraction and use. This bachelor thesis provides an overview of the existing knowledge concerning the formation, properties, and processing of industrially exploitable deposits, and the market policy of high-purity quartz raw materials. This comprehensive overview is followed by a section that focuses on deposits and potential sources of high-purity quartz raw materials in the Czech Republic (Bohemian Massif). This part was elaborated on the basis of publicly available archival sources (final exploration reports or reserve calculations), available in the Czech Geological Survey - Geofond.
Materials of pietra dura artistic technique: composition, properties, provenance and possible identification
Jaroměřský, Štěpán ; Přikryl, Richard (advisor) ; Kuchařová, Aneta (referee)
Pietra dura or Florentine mosaic is a method of assembling thin slices of variously colored minerals and rocks into meaningful patterns or scenes. This artistic technique experienced a significant flourishing in Rudolfine Prague, where many works were created by this technique with materials that have not been described in detail yet. Although decorative carbonate rocks are frequently found in works made by the technique of pietra dura, decorative siliceous materials of jasperoid character, colored red, ochre or green, are equally important. This diploma thesis deals with the mineralogical and material research of these siliceous materials. One of the main objectives of the thesis was to explore possible discriminatory characteristics of siliceous materials from Czech localities, especially from the Kozákov area, which is historically documented as a deposit of jasperoid materials since at least the 16th century. The focus of the thesis lies in a set of mineralogical-petrographic and analytical methods of research. Using optical microscopy, scanning electron microscopy with energy dispersive spectroscopy, powder X-ray diffraction, Raman spectroscopy, Mössbauer spectroscopy and observation in ultraviolet light, it was possible to determine the minerals contained in the studied jasperoid materials....
Experimental study of alkali-silica reactivity of volcanic rocks
Seidlová, Zuzana ; Přikryl, Richard (advisor) ; Vavro, Martin (referee)
(AJ) Even today, alkali-silica reaction is a significant problem in concrete-making industry. It was first described in 1940 by Stanton and since then the study of alkali-silica reaction of aggregates has proceeded notably. Despite these findings, not everything has been resolved and not all the causes and consequences of this reaction are known. To detect the alkali-silica reaction in the aggregates many methods are used, such as petrographic methods, chemical methods, and expansion tests, which examine the expansion of concrete due to the reactivity of aggregates. Petrographic methods evaluate qualitative and quantitative characteristics of aggregates but can not guarantee whether they still do not cause the reaction. Chemical tests and expansion tests provide so- called potential response (non-reactive, reactive and potentially reactive aggregates), but even they have their errors and can not be taken as a 100% indicator of the presence of alkali-silica reaction of aggregates. The thesis describes the general characteristics of alkali-silica reaction of aggregates, the mechanisms and the factors influencing its formation. It describes the fraction of the concrete in which some volcanic rocks have been used, and which are in some works identified as potentially reactive by the alkali-silica...
Modification of rock fabric of clastic sedimentary rocks due to the Schmidt hammer test
Snížek, Petr ; Přikryl, Richard (advisor) ; Vavro, Martin (referee)
iv Summary Schmidt hammer is the instrument which is used for the assessment of rock mechanical properties and this instrument is classified as the indirect method. This method is based on the assessment of rebound value (R) of the Schmidt hammer, which is measurred by the amount of rebound of the impact plunger from the surface of tested rock. Schmidt hammer is called as the non-destructive method of rock assessment and it is called as in situ testing method as well. The main objective of this work is provement, that Schmidt hammer testing is destructive method and define degree of damage which is caused in the rock mass. Sedimentary rocks were used for the testing, mostly sandstones and arkose sandstones with different types of cement. This made it possible to test the fraction of the rock mass and the relation between fraction and type of cement. The clasts of the rocks had different properties than it was possible to find the relation between grain size and fraction of the rock. Already in procedure of the testing by Schmidt hammer it was obvious, that this metod is definitely destructive. Rock surface after hitting by plunger of Schmidt hammer gains macroscopically observeable destruction. On the surface is the circular track of the plunger and the surface is grinded. It is possible to wipe the small...

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