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Monitoring the influence of concrete composition on abrasion resistance
Černá, Hana ; Novosad, Petr (referee) ; Bodnárová, Lenka (advisor)
This diploma thesis focuses on the resistance of concrete to abrasion with regard to the raw materials used for their production. In the theoretical part of the thesis are described admixtures, different types of aggregate and aggregate composition which influence the resistance of concrete to abrasion. In the experimental part, 15 different C30 / 37, S4 concrete formulations were proposed. Different types of aggregates - fecal gravel (Žabčice), biotic granodiorite (Olbramovice) and amphibolite (Želešice) have always been used in the recipes. Fine ground limestone, micro-silica, high-temperature fly ash and finely ground slag were ingredients that were added to the proposed recipes. Consistency was determined by the method of cone seating and the density of fresh concrete. In the hardened state, concrete density, compressive strength, bending tensile strength, tensile strength, watertightness, concrete absorption, and abrasion resistance were determined using the Böhm method and wide wheel method. The test specimens were tested after 7, 28, and 90 days of maturation.
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Proposal to revitalize the banks of the flooded Hulín sand pit
Skřížala, Lukáš ; Pelikán,, Petr (referee) ; Šlezingr, Miloslav (advisor)
The master´s thesis deals with the assessment of the state of the shore territory on the Brno reservoir, in the Osada area and subsequently the proposal for shore stabilization. As part of a personal visit to the area of interest, photographic documentation, geodetic focus and subsequent assessment of the current state of the abraded shores were made. Using the geodetic focus and data of water heights on the reservoir provided by the Povodí Moravy, s.p. the most numerous in the reservoir was evaluated in 2007-2017, the coastline retreat and the proposed shore stabilization were determined. There was suggested totaly eight measures were proposed against the further retreat of the shore line, which were incorporated into schemes and visualizations.
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Development of abrasion resistant concrete
Procházka, David ; Darebník, Zdeněk (referee) ; Hela, Rudolf (advisor)
The resistance of concrete to abrasion is an important feature particularly for transport and water management structures where the surface is exposed to abrasion. Bachelor thesis deals with individual influences on improvement of abrasion resistance of concrete surface. Furthermore, the search of test methods used for testing abroad. In the practical part, we assess the effect of curing agents on resistance to abrasion, water jet and tensile strength by tear-off test.
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Combined coatings against mechanical wear and corrosion low carbon steel
Brožek, Vlastimil ; Pokorný, P. ; Kolísko, J. ; Vokáč, M. ; Mastný, L. ; Stoulil, J.
In this study, special ceramic coatings were prepared on low carbon steel (1.0060 - EN 10027-2) via the plasma spraying technique using a WSP®-H plasma generator with output of up to 40 kg/h of aluminum oxide. Corundum coatings were deposited directly on the surface of steel plungers equipped with an anti-corrosion interlayer of zinc phosphate. Coating adhesion properties were tested using pin-off tests (modified ISO 4624) and reached a maximum value of 26 MPa. Corrosion resistance was evaluated by measurements of impedance spectra in the 100 kHz - 10 mHz range in a water solution of sodium sulfate. The capacity of electric double-layer varied depending on the porosity and thickness of the coating. Low-porosity coatings of >1.5 mm thickness had RCT 1.29·105 Ω·m2. The abrasive resistance of coatings was measured by rotary/machining test with SiC cutting knives, using a downforce of 50 kg·cm-2. Abrasion losses decreased with the quality of finish - starting at 0.00266 g cm-2 min-1 down to virtually zero losses after polishing the surface below Ra = 0.55 micro m.
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Mortar with alkali-activated matrix
Černá, Hana ; Hela, Rudolf (referee) ; Bodnárová, Lenka (advisor)
The thesis addresses the issue of alkali-activated materials and their manufacturing components. In the theoretical part the description of such materials is provided and the requirements for source materials are defined. The theoretical part further addresses the resistance of alkali-activated materials and their lifespan - namely sulphate resistance, chloride resistance, acid resistance, frost resistance, porosity, carbonation, resistance, abrasion resistance and heat resistance. The experimental part of the thesis focuses on compounding four different mixtures of alkali-activated materials. In the loosened stage, the weight was measured. In the hardened stage the weight was measured as well as the tensile strength when bending, the strength under pressure applied, heat resistance, water and defrosting chemicals resistance and formation of cracks.
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Slurry surfacing - composition and quality issue
Dostál, Filip ; Koudelka, Tomáš (referee) ; Hýzl, Petr (advisor)
This thesis is focused on slurry surfacing technology, particularly on microsurfacing. The theoretical part describes the differences between the slurry seal and microsurfacing. Ingredients for the production and laying. There are also described their advantages. The practical part presents proposal of mixture and demonstrate that the service of life of the emulsion mixture is closely related to the content of residual binder and composition of microsurface.
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Causes and consequences of human tooth wear
Ibrová, Alexandra ; Velemínská, Jana (advisor) ; Stránská, Petra (referee)
During individual's life is human dentition affected by tooth wear. There are various causes of human tooth wear and dentition of every individual is affected during lifetime. Dental wear occurs in dentition of both recent and past populations. Tooth wear can be caused by diet, geographical and climatic conditions where the population lives in, or by specific behaviour. In past populations is the type of tooth wear important information for reconstruction of lifestyle of these populations. In recent populations is tooth wear associated mainly with diet and dental hygiene, and the research in this area deals with the question, how to protect the dentition from damage. Human tooth wear plays a special role in diagnostics of eating disorders. The purpose of this bachelor thesis is to describe abrasion, attrition and erosion, and summarize causes and consequences of human tooth wear of recent and past populations.
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Wear regimes of aluminium alloys
Slivka, Václav ; Zapletal, Tomáš (referee) ; Šperka, Petr (advisor)
This thesis deals with the research of the wear regimes of the selected aluminium alloy in the conditions of dry friction. The aim of this work is the evaluation of the measure of an abrasive and adhesive wear of this alloy. This evaluation is made from the experiments which are made on the base of the knowledge of the research study. The dependence of the wear on the sliding speed and load, the friction on the sliding speed and load and the dependence of the normalised pressure on the normalised speed, so called the map of wear, are given on the base of the results of the measure.
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Durability of alkali-activated materials
Zourek, Milan ; Hela, Rudolf (referee) ; Bodnárová, Lenka (advisor)
This bachelor’s thesis deals with durability of alkali-activated materials and the use of them in aggressive surroundings, especially in sewer systems. The first half of the theoretical part summarizes requirements for concrete sewer pipes. The most common linings and coatings used in concrete sewer systems are mentioned. The second half of the theoretical part deals with alkali-activated materials, raw materials used for their preparation and their durability. Concretely sulfate attack resistance, chloride attack resistance, acid attack resistance, abrasion, porosity, freeze-thaw resistance, thin layer applications and cracking tendency. In the experimental part of this bachelor’s thesis there were proposed five types of alkali-activated materials application in the aggressive environment of sewer systems. Density and consumption of alkali-activated material by thin layer application was determined as fresh properties. Material was monitored during its solidifying and hardening, especially for crack formation. As hardened properties density, flexural strength, compressive strength, adhesion of thin layer to concrete, thickness of thin layer, freeze-thaw resistance, resistance of surface to water and defrosting chemicals were determined.
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