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Influence of cutting conditions on durability of cutting inserts during turning
Hynčica, Vojtěch ; Fiala, Zdeněk (referee) ; Jaroš, Aleš (advisor)
The aim of present thesis is to determine the influence of the cutting conditions (the cutting speed, the feed, the depth of cut) on wear and durability of cutting inserts during machining process of the Inconel 718 alloy. In theoretical part thesis describes technology of turning, cemented carbides, their production and coating; it also deal with how the wear of the tool arises and how the tool wear progresses. In experimental part of this thesis we describe the cutting material, the machine, the machine tool and the experiment procedures. Measured values showed, that the durability of cutting inserts decreases depending on the cutting speed. We have determined that there is no direct correlation between the tool wear and the (increasing) level of the feed and the depth cut.
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Ground retaining structure for cut & cover metro station in Qatar
Kočičková, Veronika ; Račanský, Václav (referee) ; Uhrin, Michal (advisor)
The aim of this thesis is to assess the geological conditions and durability of the cut and cover metro station in Qatar. Furthermore, the thesis deals with the construction sequence and structural checks of selected elements of the structure. The geological conditions were evaluated on the basis of an extensive geotechnical investigation that was conducted at the construction site. This research also gave necessary information for durability design. After the assessment of the ground conditions in the thesis, it was possible to choose suitable retaining walls and lateral support system and continue with a plan of construction sequence. A diaphragm wall and mezzanine level prop were chosen for the structural check. In case of the wall, the main load was caused by bending moments of a big significance, therefore the wall was designed to the envelope of these moments obtained from software Plaxis. Furthermore, it was necessary to consider the interaction of bending moments and normal forces for the design of the prop. For both elements, reinforcement of bigger diameters was designed.
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Study of the influence of additions on the durability of aerated concrete
Halešová, Adéla ; Voves, Jiří (referee) ; Hubáček, Adam (advisor)
The aim of this work is to summarise and consider the possibilities of using admixtures and their influence on the durability of aerated concrete.This bachelor's thesis is based on research findings concerning aerated concrete. Furthermore, it deals with the study of inert and active additions. The experimental part is focused on testing trial samples with the addition of admixtures. It examines what is the rate of the possible chosen physically-mechanical features such as the rate of air density, the durability of surface against the effect of water and chemical defrosting substances and achieving the required strength.
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The verification of durability of surface layer by pull-off testing
Fujačková, Hedvika ; Komárková, Tereza (referee) ; Kocáb, Dalibor (advisor)
The theoretical part of this bachelor's thesis defines the basic properties, categorization, and use of the individual components of concrete and presents the properties of fresh and hardened concrete, especially the tensile strength. Furthermore, the thesis addresses the problem of durability assessment of concrete, which depends directly on the quality of the surface layer. The experimental part of the thesis focuses on executing of a pull-off test and examines the surface layer tensile strengths of various concrete mix designs. The thesis examines how the results of the measurements correspond with other published results.
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Development of structural concrete with power plant ash
Ťažký, Martin ; Sokol, Pavel (referee) ; Hela, Rudolf (advisor)
Worldwide production of concrete is increasing, what has a negative environmental load of cement production. That is due to effort in building construction, also concrete production, greater use of the secondary raw materials. Fly ash is the most commonly used secondary raw material. His used has a very good impact on the economy and ecology of production and positively affects on the properties of concrete in both the fresh and hardened state. The aim of this bachelor's thesis was to improve its use in concrete, using a minimum void fraction of dry mix cement-fly ash.
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SCC with secondary raw materials
Ťažká, Lucia ; Ťažký, Tomáš (referee) ; Hela, Rudolf (advisor)
Bachelor thesis is focused on the possibility of using secondary raw materials and their application to the production of SCC. Large part deals with impurities of type I and its application results mainly from abroad. Furthermore, this work examines the impact of different types of impurities on the resulting concrete durability in various aggressive environments. The practical part is focused on the use of chemically non-reactive additives of type I instead of the commonly used additives of type II which are used to replace part of cement and the resulting design and manufacture of low-strength SCC using appropriate additives.
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Cement composite materials with polypropylene fibers
Preisner, Martin ; Hela, Rudolf (referee) ; Bodnárová, Lenka (advisor)
This thesis deals with summarizing the possible effects of the addition of polypropylene fibers, especially low temperature plasma treated on the properties of cement composites and concrete. They are given basic information and distribution of polypropylene fibers. It describes the finish polypropylene fiber low-temperature plasma. The experimental part focuses on the effect of dispersion of polypropylene fibers treated plasma in the cement matrix.
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High volume fly ash concrete
Kučera, Jakub ; Sokol, Pavel (referee) ; Hela, Rudolf (advisor)
Bachelor thesis consist of two parts. The aim of teoretical part is to explore possibilities of usage and properties of high volume fly ash concrete with 40 – 70 % cement replacement. To make an overview of development of strength, durability in various environments, reduction of heat evolution etc. The aim of the experimental part is to compare properties of various class concretes with various amount of fly ash.
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