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Studying the behavior of concrete at high temperatures
Žák, Michal ; Sitek,, Libor (referee) ; Bodnárová, Lenka (advisor)
This bachelor's thesis is focused on behavior of concrete at high temperatures. The theoretical part describes processes, which take place in concrete at thermal loading and further there was described testing of concrete at high temperatures. Next there was described influence of high temperatures on each component of concrete and design of appropriate components for concrete exposed to high temperatures. In experimental part mixes was made with greywacke aggregate, amphibolite aggregate and with the addition of polypropylene fibers. In these mixes was determined the effect of high temperatures on the density of concrete, dynamic modulus of elasticity of concrete and compressive strength of concrete.
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Possibilities of rehabilitation of concrete structures damaged by high temperaturesv
Vovesný, Václav ; Sitek,, Libor (referee) ; Bodnárová, Lenka (advisor)
The bachelor thesis studies the behavior of the cement concrete exposed to high temperatures. The theoretical part describes the processes in the concrete structure and its individual components. It also describes the diagnostic possibilities of the concrete and its subsequent rehabilitation. In case of rehabilitation and surface pretreatment possibilities, the emphasis was mainly placed on the high-speed water jet. Physical-mechanical properties of the samples were verified by heavy load of pressure from high-speed water jet and high temperature in the experimental part.
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Properties of cement composites with fiber reinforcement
Jankech, Filip ; Sitek,, Libor (referee) ; Bodnárová, Lenka (advisor)
This thesis summarizes the knowledge of the possibility of using organic fibres as dispersed reinforcement into cement composites. It is concretely a summary of knowledge about the types and properties of synthetic and cellulosic fibres, their influence on the properties of fresh and hardened cement composite and lastly a description of the fire resistance of cement composites and the effect of organic fibres on the action of those composites at high temperatures and in the presence of fire. The experimental part is supposed to verify the effect of the cellulose fibres on increasing the durability of the cement composite at high temperatures.
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High-grade concrete using nanoparticles
Labaj, Martin ; Bodnárová, Lenka (referee) ; Hela, Rudolf (advisor)
The aim of this paper is to summarize and assess the possibility of using nanoparticles as additives in high performance concrete. These particles have the ability to improve the mechanical and physical properties of cement composites or even gave them brand new ones. Industrial use, however, is hampered by several obstacles. In particular, it is the task of effective incorporation of nanoparticles into the matrix, the health and environmental risks and, last but not least, the financial costs. The experimental part of the work deals with the first-mentioned problem, namely with dispersing carbon nanotubes in aqueous solution and their subsequent integration into the structure of cement mortar.
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Properties of Fiber Reinforced Plastics
Jastrzembská, Alena ; Petránek, Vít (referee) ; Bodnárová, Lenka (advisor)
This thesis deals with the theoretical part of raw materials, production and properties of composite materials with fiber reinforcement and polymer matrix. It also gives a brief overview of selected prominent Czech and foreign producers of composite materials with polymer matrix and fiber reinforcement. The practical section deals with testing the durability of selected composite profiles immersion in aggressive environments and testing of compressive strength.
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Properties of concrete with cement matrix at high temperatures
Fiala, Jiří ; Dvořák, Karel (referee) ; Bodnárová, Lenka (advisor)
This bachelor´s thesis deals with the behaviour of the cement concrete at high temperatures depending on the aggregate and cement type. The theoretical part describes the processes in the concrete structure at high temperatures affecting the individual concrete components. The design of concrete structure with basalt aggregate and four types of cement in the experimental part was carried out. The proof of physical-mechanical properties after thermal load was reviewed, particularly change of density, compressive strength and tensile strength in bending. The X-ray diffraction analysis was carried out with prepared test samples.
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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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Properties of cementitious composites with plasma treated polymer fibers
Počekajlo, Václav ; Hela, Rudolf (referee) ; Bodnárová, Lenka (advisor)
Modification of polymer fiber low temperature plasma is one of the ways to enhance the properties of modified fibers as follows. This work aims to evaluate the effect of plasma treated polypropylene fibers on the rheological properties of cement composites. The theoretical part describes the treatment and the effect of plasma treatment on polymer fibers. The influence of polypropylene fibers treated by low-temperature plasma on the workability of concrete. The practical part is described and evaluated experimental verification of the influence of the addition of commercially available fibers and fibers treated plasma on the rheological properties of fresh cement composite.
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Fibre reinforcement with plasma in cement composites
Žižková, Lucie ; Hela,, Rudofl (referee) ; Bodnárová, Lenka (advisor)
The usage of polymer fibres can be increased by the new progressive method of the plasma treatment. This thesis is focused on verification of the influence of the low-temperature treatment on polymer fibres´ surface used in concrete. The treatment of polypropylene fibres in low-temperature plasma is described in the theoretical part. The impact of the treatment on the volume differences of cement composites is also evaluated. The influence of the addition of commercially available fibres and plasma treated fibres on the volume differences of cement composites is also experimentally verified.
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The application of high-speed water jet in civil engineering
Hudský, Petr ; Hela,, Rudolf (referee) ; Bodnárová, Lenka (advisor)
Bachelor thesis is focused on gathering available information about the use high-speed water jet in civil engineering The thesis describes types of water jets, used in industry, focusing in detail on the use in construction. Mentioned are also selected tools for rehabilitation. Was studied experimentally the influence of pressure water jets for various types of concrete, cutting depth, strength and pull-off test with the evaluation and comparison.
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