National Repository of Grey Literature 61 records found  previous11 - 20nextend  jump to record: Search took 0.01 seconds. 
Possibilities of using recycled concrete as fine aggregate replacement in cement screeds
Nováková, Iveta ; Brožovský,, jiří (referee) ; Hubáček, Adam (advisor)
The bachelor thesis deals with summary of knowledge about cement-based screed with partial replacement of natural aggregates by recycled aggregates. Special emphasis is given to describing and studying characteristics of cement-based flowscreed. In this study are described feedstocks with requirements which they must meet and test methods for testing properties of screeds. One part is also given to practical application of cement-based flowscreed with partial replacement of natural aggregates by recycled aggregates.
Issues of design and testing of waterproof concrete fot tunnel lining
Merta, Michael ; Voves, Jiří (referee) ; Hubáček, Adam (advisor)
The diploma thesis deals with the issue of waterproof concrete and testing its properties. The theoretical part is conceived through research on existing knowledge relating to waterproof concrete. Emphasis is placed on the possibility of using a waterproof concrete for structures, such is e.g. tunnel lining. The experimental part is focused on the laboratory testing of waterproof concrete. Particulary examined was the effect of various admixtures as a partial replacement of cement. Monitored was the development of compressive strength and flexural strength, development of temperature during hydration in the early stages of maturation of concrete, water resistance of concrete, concrete surface resistance to water and chemical de-icing agents, as well as development of shrinkage during concrete maturation.
Study of influence of admixtures on electrochemical characteristics electrode materials for lithium-ion batteries
Nejedlý, Libor ; Jirák, Tibor (referee) ; Sedlaříková, Marie (advisor)
The bachelor project deals with new intercalation materials with admixtures for positive electrode of lithium-ion accumulators. Concretely, the project works with new preparation methods of electrode materials and compares them with long-established industrial process. For this purpose were used electrochemical measurements and structure analysis obtaining materials. The theoretical part of the project is devoted summary of electrochemical power sources, electrochemical reactions, recycling and future of Li-ion batteries. The practical part describes electrochemical methods, measurements and discusses achieved results.
Study of the effect of selected types of aditives on the properties of cement composites
Kavka, Lukáš ; Ťažký, Tomáš (referee) ; Bodnárová, Lenka (advisor)
The diploma thesis describes admixtures for concrete. It deals with the influence of admixtures on the properties of cement composites in the fresh and hardened state. The theoretical part described the individual components of concrete, where the main attention was focused to inert admixtures and their effect on mechanical properties, shrinkage, resistance of cement composites to aggressive medium. Furthermore, the effect of admixtures on concretes with recycled aggregates was described. In the first stage of the practical part, cement mortars with 25, 35 and 50% replacement of cement admixtures were created. In the second stage, concretes with admixtures and a minimum strength class of C30/37 and C50/60 were created. Finely ground granulated slag, micronized limestone and granite stone dust were used as admixtures in mortars and concretes. The change of properties in the fresh and hardened state was observed on cement composites.
Possibilities of using different types of admixtures in shotcrete technology
Berčík, Martin ; Brožovský, Jiří (referee) ; Hubáček, Adam (advisor)
The Bachelor’s thesis is conceived in the form of research findings on current knowledge of inert and active ingredients and their effects on the shotcrete. It focuses mainly on the composition of individual ingredients, their function executing in the concrete mix and explains how they affect the selected physical and mechanical properties. The work enlightes the importance of using co-products from the industry production as an additive to concrete in terms of both ecological and partly economical.
Research on the Preparation of Masonry Mortars
Koláček, Tomáš ; Dvořák, Karel (referee) ; Gazdič, Dominik (advisor)
This thesis deals with development in the preparation of masonry mortars. The theoretical part focuses on basic knowledge of mortars, individual types of mortar, preparation methods and individual components from which the mortar is composed. The practical part deals with the proposed reference and modified mortar mixtures and compares their technological properties.
Monitoring of the wheat quality for food production
Slavíčková, Radka ; Hýsková, Eva (referee) ; Omelková, Jiřina (advisor)
The aim of this study was to monitor the quality of wheat Triticum aestivum, imported into the laboratory MORAGRO after harvest by eight different suppliers, and to evaluate the main quality parameters decisive for the final use of cereal crops. The introduction of the theoretical part was devoted to understanding commercial and agricultural importance of wheat and description of morphological and physiological characteristics of wheat grain. The core of the theoretical part has been focused on the description and explanation of physical and chemical properties of the wheat grain, which largely affect the final product quality of wheat. External factors affecting final quality and yields of wheat were also commented. The experimental part was based on measurements of main quality parameters of wheat (moisture content, bulk density, falling number, amount of gluten and the wheat proteins, sedimentation value and content of additives and impurities). In most cases, measurements were carried out using automated instruments. The quality of wheat was determined based on the obtained results, which allows deciding, whether it is appropriating for food production.
Mechanical activation of admixtures in concrete and verify the impact on physical and mechanical properties of fresh and hardened concrete
Prokopec, Zdeněk ; Holák, Michal (referee) ; Hela, Rudolf (advisor)
This work is devoted to describe the possibilities of mechanical activations of admixtures used in concrete. Then, the verification options of grind fly ash, both from brown and black coal, from the classical as well as fluidized combustion and examination their impact on physical and mechanical properties of concrete, especially on long-term development to old age 180 days. Further attention is paid to assessing the impact of the use of mechanically activated fly ash on hydration heat evolution and the associated volume changes in the age of 1 to 90 days. In this work are presented the results of basic technological tests on concretes using admixtures, especially fly ash.
Proposition of conception of using micro-additions for High Performance Concrete
Lédl, Matěj ; Hela, Vlastimil (referee) ; Hela, Rudolf (advisor)
The modern, contemporarily used cement composite types make use of various additives. This diploma thesis is focused on designs of mortars that have been enriched with micro and nano additives, which lead to higher mechanical strength through optimized grading of mortar mixes. This thesis also evaluates the influence of material properties on resulting properties of mortars in fresh and hardened state.
Influence of pressure and additives on cycle life of lead acid battery for hybrid electric vehicle
Přívozník, Tomáš ; Bača, Petr (referee) ; Křivík, Petr (advisor)
This master’s thesis deals with lead acid battery in hybrid electric vehicles which operating at mode of partial state of charge (PSoC). In this mode, there is often a negative electrode degradation mostly due to irreversible mechanism of suphation. The idea of this work is detect ideal value of mechanical pressure exerted on active mass of negative electrode in combination with additives to prevent mechanism of sulphation and lead to increased cycle life of lead acid battery.

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