National Repository of Grey Literature 36 records found  previous3 - 12nextend  jump to record: Search took 0.01 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...
Climate impact on archaeological monuments in Prague Castle
Pokorný, Šimon ; Weiss, Tomáš (advisor) ; Kozlovcev, Petr (referee)
This thesis deals with the question of the influence of climate on archaeological monuments beneath the pavement of the III. courtyard of Prague Castle. The complex archaeological site is threatened by the effects of several climatic factors, especially water and temperature changes, which cause weathering processes, and the historical building material in this area is subsequently degraded. The theoretical part of this thesis first deals with the study of historical building materials in the excavation area, with a focus on marlstone and clay slate, which are most susceptible to various types of weathering. Subsequently, degradation processes that affect the state of the present material are discussed, particularly processes related to water penetration through the material, chemical weathering caused by salt crystallization, and swelling of clay minerals, a process that often occurs in clay slate. The last chapter of the theoretical part outlines the impact of future climate change on the action of these processes. The practical part of this thesis focuses on research into frost and salt weathering cycles, particularly the determination of the frequency of cycles in one year of continuous measurement. Moisture and temperature values over time from sensors that are evenly distributed throughout...
Survey of the terrain and structures under the floor of The Mother of God Church (The Telč Old Town)
Válek, Jan ; Kotková, Kristýna ; Kozlovcev, Petr
A non-destructive survey of the building structures hidden under the current level of the Church of the Mother of God in the Old Town of Telč was carried out using ground-penetrating radar. The survey revealed the occurrence of hidden constructions that are related to the current concept of the church and its construction solution.
Selection of mortars samples for radiocarbon dating
Válek, Jan ; Kozlovcev, Petr ; Fialová, Anna ; Kotková, Kristýna ; Frankeová, Dita ; Skružná, Olga ; Maříková-Kubková, Jana ; Tomanová, Pavla ; Herichová, Iva ; Světlík, Ivo ; Pachnerová Brabcová, Kateřina ; Šimek, Pavel
Radiocarbon dating of organic residues may not always correctly determine the age of analysed historic mortars. Therefore, it seems advantageous to use of carbon dating of the carbon contained in the structure of the lime mortar, which will provide representative data of the age of the investigated structure. The methodology presents basic instructions and rules for sample selection, processing, and evaluation. The aim of this methodology is the identification of cases where the radiocarbon dating of a binder is appropriate and to define the reasons why some binder systems fail to provide relevant results.
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Preparation of mortars samples for radiocarbon dating by mechanical separation
Válek, Jan ; Kotková, Kristýna ; Fialová, Anna ; Kozlovcev, Petr ; Králová, Karolína ; Světlík, Ivo ; Pachnerová Brabcová, Kateřina
The methodology establishes the procedure for mechanical separation of the binder from the mortars to determine their age using the radiocarbon method. Along with the procedure, there is also a method of verifying the quality of purification using optical microscopy supplemented with cathode luminescence. The methodology is developed on the basis of the current state of knowledge and presents the basic sample preparation procedure in the form of a detailed description of the proven method of mechanical separation of the binder from lime mortar samples together with possible problems and an evaluation of the separation quality.
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Survey of the castle courtyard, garden and armbashill in Telč
Válek, Jan ; Kotková, Kristýna ; Kozlovcev, Petr
A non-destructive survey of structures hidden beneath the current level of the castle 'Little courtyard', garden and armbashill in Telč using ground-penetrating radar was conducted.
Material composition of paving in the Pilgrimage Church of St John of Nepomuk at Zelena Hora
Válek, Jan ; Skružná, Olga ; Kozlovcev, Petr ; Viani, Alberto ; Frankeová, Dita ; Shaikh, Nigar
The aim of the study was to verify the material composition of the paving and to evaluate the possible production of replicas. The sampled material was analyzed by using optical microscopy, X-ray diffraction, X-ray fluorescence and thermal analyses. The results showed that the studied paving is of ceramic origin and its composition corresponds to burnt brick clays of local raw materials.
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Determination of reference parameters for evaluating the strengthening of degraded sandstone masonry of the Cathedral of St. Vit at Prague Castle
Válek, Jan ; Kozlovcev, Petr ; Fialová, Anna ; Slížková, Zuzana ; Kotková, Kristýna ; Svoboda, Milan ; Koudelková, Veronika
Sandstone materials exposed to weather conditions degrade naturally, consequently consolidation of these materials is often required. The aim of this research was to evaluate the impact of four commercials organosilicate consolidants on degraded sandstones, which were used during the neogothic rebuilding of st. Vithus Cathedral at the turn of the 19th to 20th century. The depth of penetration of consolidants into the sandstone porous system and the impact of consolidants on the physical properties of sandstones, namely on the hydrofobicity, water absorption and evaporation, were evaluated primarily. According to the test results, all four consolidants should be suitable for consolidation of sandstones mentioned above even though the results varied slightly between consolidants. For final chose of appropriate consolidant, it is necessary to consider the properties of the treated sandstoned and the technological conditions of the application given by the manufacturer.
Ceiling plaster in the Church of Master Jan Hus in Česká Lípa. Plaster in the Stauss system
Válek, Jan ; Skružná, Olga ; Kozlovcev, Petr ; Slížková, Zuzana ; Frankeová, Dita ; Kotková, Kristýna ; Viani, Alberto
The studied ceiling plasters were sampled the Mistr Jan Hus Church in Česká Lípa. The material consisted of several layers of paint. The aim of this research was to characterize the individual layers of plaster in the Stauss system.
Influence of the mineralogical composition of raw material on phases formed during the burning of hydraulic lime and natural cement
Kozlovcev, Petr ; Přikryl, Richard (advisor) ; Hladil, Jindřich (referee) ; Škvára, František (referee)
Natural hydraulic lime and natural cement have been used in the building industry for centuries. These inorganic hydraulic binders are called "traditional" or "alternative" because they can, in some cases, substitute modern Portland cement. The recent increased interest in these binders is due not only to their use in restoration practices, but also because their production and use is less energetically demanding than in modern cements. Historically, many types of hydraulic binders were produced in the regions of Bohemia and Moravia. However, much information has been lost about their manufacturing process, which raw materials were used, and we are uncertain of the exact character and properties of the burned material. To date, studies have only addressed the impact of the chemical composition of raw material on the parameters of the burned material - all this is well known for Portland cement, much less for other types of hydraulic binders. The aim of this dissertation was to study the various types of raw materials (limestone containing non- carbon admixtures) and to understand the characteristics of their respective hydraulic lime and natural cement. This was done by analyzing the impact of conditions (highest achieved burning temperature and time of burning) and the mineral and chemical...

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