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Optical measurement of deformations of flange joints
Schmidtová, Markéta ; Mendřický, Radomír (referee) ; Hurník, Jakub (advisor)
The diploma thesis addresses the topic of optical measurements of flange joints during tightening and thermal loading. Commercially available optical systems with decreasing invasiveness were compared in opportunity which offer to an industrial environment. Various conditions are evaluated in 3D (scanning, DIC) as well as in 2D (DIC). The data for evaluation of sensitivity and system accuracy together with the evaluation of the data range were obtained by the measurement. Data evaluation showed the same accuracy for 2D and 3D system and the possibility of quality inspection of the joint by assessing the inspection dimensions in operation.
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Studying the behavior of concrete at high temperatures
Tillová, Jana ; Herka, Petr (referee) ; Bodnárová, Lenka (advisor)
This master‘s thesis is focused on the study of the behavior of cement concrete at high temperatures with a focus on monitoring the impact of aggregate and cement type. This work describes the processes in aggregates and cement matrix at high temperatures. The theoretical part describes the selestion of a suitable aggregate and cement for the surroundings with potential exposure to high temperatures. In the experimental part is given design of composition of a concrete with two types of aggregates and four cements. It has been suggested 8 recipes. Changes were observed densities, compressive strength and tensile strength in bending, calculate the velocity of propagation of waves with ultrasonic pulsed method. Also evaluated the appearance of the surface samples after thermal load – cracks on the surface and measure the maximum crack width.
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Pile Foundations - Energy Piles
Hoza, Martin ; Leiter, Augustin (referee) ; Glisníková, Věra (advisor)
At a time when ecology and renewable energy sources come to the fore, the use of geothermal energy appears to be one of the suitable alternatives. The aim of this paper is to explain the function of ground source heat pumps, to mention factors affecting the efficiency of the system and discuss the technology of energy piles realization. This paper also focuses at risks associated with the soil temperature influencing and shows examples of realization.
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The concrete with a higher resistance to high temperatures
Mikulinec, David ; Hela,, Rudolf (referee) ; Bodnárová, Lenka (advisor)
The result of this master’s thesis is acquaintance with the issues of cement concrete resistance to high temperatures. This work describes the processes ongoing in the structure of concrete at extreme thermal loads and analysis of effects of high temperatures on the individual components of reinforced concrete structures is given, then influence of high temperatures and fire on the aggregates, matrix, reinforcement steel and the resulting changes in their properties. In the experimental part is given design of composition of concrete with a higher resistance to high temperatures and subsequent verification of the physico-mechanical properties of sample of concrete after exposure to temperatures at intervals of 200 ° C, 400 ° C, 600 ° C and 900 ° C. In individual recipes were observed changes of volume weight, changes of compressive strength and tensile strength flexural , tensile strength of surface layers and the occurrence of cracks and then were compared the results of thermally loaded and unloaded samples. The benefit in this issue is to evaluate the surface appearance of samples after heat load - study of area of crack and measurement of their width - was used according to the methodology's authors Xing, Hebert, Noumowe a Ledesert given in Cement and Concrete Research. This methodology allows to quantify changes of surface, after temperature load.
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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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Possibilities of using light artificial aggregate based on sintered high-temperature fly ash in heat-resistant concrete structures
Mazán, Tomáš ; Sedlmajer, Martin (referee) ; Křížová, Klára (advisor)
The final thesis describes contemporary knowledge of research and development in the area of the heat-resistant concrete constructions with using porous aggregate from flying ash. The theoretical part introduces the production and the agloporit aggregate basic features. The principles of using in the incoming materials of light weight concrete are presented next. The thermal loading with influence at concrete constructions and the other individual materials is also mentioned in the final thesis. The experimental part of the thesis deals with the impact of lightweight aggregate quantity on the high temperature resistance. Conclusion pays attention to the obtained results evaluation and to the composition an optimal formula LWAC, which could be able to resist short-term thermal loading.
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Durability of repair materials with higher fire resistance for concrete structures
Počekajlo, Václav ; Dohnálek,, Pavel (referee) ; Bydžovský, Jiří (advisor)
This dissertation deals with the study of durability and degradation repair mortars for reinforced concrete structures. In its theoretical part, there are the research findings on the behavior of repair mortars exposed to corrosive environments with different exposure time and selected high temperatures. Processes occurring in repair mortars during their loading at high temperatures or when exposed to chemically aggressive environments are described, We can find recipes designed for cementitious binder based with a specific replacement using slag or fly ash in its practical part. The object of the research was to determine the durability of the proposed repair mortars, and determine their suitability for use on concrete structures, which may be exposed to a synergistic effect of chemically aggressive environments with high temperatures simulating fire.
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Measurement of Acoustic Parameters of Building Materials by Pseudorandom Sequence
Carbol, Ladislav ; Semerák,, Petr (referee) ; Koktavý, Bohumil (referee) ; Vydra,, Vítězslav (referee) ; Martinek, Jan (advisor)
The thesis deals with research of pulse compression of the acoustic signal in terms of applications in civil engineering. Based on the study and analysis of these methods, automated measuring equipment for non-destructive testing with pseudorandom sequence of maximum length and automated signal analysis, have been designed and implemented. In a single test cycle are obtained three parameters that characterize the linear and nonlinear behavior of the sample. A nonlinear parameter, Time of Flight of ultrasonic wave in the sample is further in the work compared with the conventional pulse measuring, and spectral analysis is compared with the method impact-echo. Functionality and optimization of the testing method was performed on a total of three sets of test pieces made of various building materials. The experiments proved simple result interpretation, and high sensitivity to structural damage associated with temperature loading. The results were correlated with conventional nondestructive methods and by destructive testing was measured change in compressive strength and flexural strength. This work also includes continual measurement of fundamental frequency influenced by moisture on a mortar sample. Use of pulse compression signal is in the civil engineering quite unusual. Only in recent years this topic is discussed in scientific articles with increasing frequency. Great potential lies in the association of three test methods into a single. Beneficial is high test speed and measurement reproducibility, but also theoretical possibility of testing massive test elements.
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Optical measurement of deformations of flange joints
Schmidtová, Markéta ; Mendřický, Radomír (referee) ; Hurník, Jakub (advisor)
The diploma thesis addresses the topic of optical measurements of flange joints during tightening and thermal loading. Commercially available optical systems with decreasing invasiveness were compared in opportunity which offer to an industrial environment. Various conditions are evaluated in 3D (scanning, DIC) as well as in 2D (DIC). The data for evaluation of sensitivity and system accuracy together with the evaluation of the data range were obtained by the measurement. Data evaluation showed the same accuracy for 2D and 3D system and the possibility of quality inspection of the joint by assessing the inspection dimensions in operation.
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Possibilities of using light artificial aggregate based on sintered high-temperature fly ash in heat-resistant concrete structures
Mazán, Tomáš ; Sedlmajer, Martin (referee) ; Křížová, Klára (advisor)
The final thesis describes contemporary knowledge of research and development in the area of the heat-resistant concrete constructions with using porous aggregate from flying ash. The theoretical part introduces the production and the agloporit aggregate basic features. The principles of using in the incoming materials of light weight concrete are presented next. The thermal loading with influence at concrete constructions and the other individual materials is also mentioned in the final thesis. The experimental part of the thesis deals with the impact of lightweight aggregate quantity on the high temperature resistance. Conclusion pays attention to the obtained results evaluation and to the composition an optimal formula LWAC, which could be able to resist short-term thermal loading.
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