National Repository of Grey Literature 128 records found  previous11 - 20nextend  jump to record: Search took 0.02 seconds. 
Determination of compressive strength of concrete in prefabricated units using NDT methods and advanced regression diagnostics
Uchytilová, Jitka ; Kocáb, Dalibor (referee) ; Misák, Petr (advisor)
This thesis deals with the rebound hammer method as a tool for approximation of the time limit for handling the concrete. The theoretical part is focused on three fields of knowledge - rebound hammer test, production of precast concrete components and statistical data analysis. The following practical part deals with the design of two single-parameter linear functions for two types of rebound hammer testers - SilverSchmidt L and SchmidtOriginal N. Statistical data processing is completed by the analysis of influential points by using the Cook’s distance. The resulting statistical models are compared with commonly used relationships.
Methodology of historical bricks and masonry tests
Bartoň, Vojtěch ; Anton, Ondřej (referee) ; Cikrle, Petr (advisor)
This diploma thesis is focused on methodology for sorting of solid fired bricks for reconstruction of historical buildings. The theorethical part of this thesis includes description of production technology of solid fired bricks and diagnostic methods. In practical part there are these methods aplied on the solid fired bricks, which are intended for reconstruction of the bridge in Sedlec. There are monitored changes in structure of solid fired bricks caused by repeated freezing and defrosting. This changes are monitored by resonant frequency method and ultasonic pulse method.
Monitoring and Analysis of Corrosion of Reinforcing Steel in Reinforced Concrete Elements and Structures Using the Acoustic Methods
Timčaková, Kristýna ; Semerák,, Petr (referee) ; Medveď,, Igor (referee) ; Vaněrek, Jan (referee) ; Chobola, Zdeněk (advisor)
The dissertation thesis deals with the study of non-destructive acoustic methods as instruments for monitoring and analysing corrosion of reinforcing steel in reinforced concrete elements. Four acoustic methods were selected for this task - the impact-echo method, the nonlinear acoustic spectroscopy method, the acoustic emission method, and the ultrasonic pulse velocity method. To verify the functionality of these methods, testing was carried out on three sets of reinforced concrete samples that had been exposed to the effects of sodium chloride, which corroded the embedded steel reinforcement in these samples. Suitable parameters were proposed for individual acoustic methods to monitor corrosion of the reinforcements. In addition, experiments were designed to demonstrate the ability of the selected acoustic methods to reveal the corrosion of steel reinforcement and its influence on the concrete matrix and to assess the condition of the degraded elements and structures. The analysis of the measurement results based on their comparison shows the advantages and disadvantages of the individual methods and of their practical applications. To verify the results, correlation with common methods that are currently used for the study of corrosion was carried out and included for example the electrical resistivity measurement of the reinforcement and simultaneous monitoring of the sample surface using a confocal microscope to record the development of microcracks during the degradation.
Use of ultrasound testing of concrete in bridge structures
Olejková, Sabina ; Komárková, Tereza (referee) ; Cikrle, Petr (advisor)
There are analyze kinds of diagnostic methods in terms of bachelor’s thesis. It is written about principles of ultrasonic pulse method and its options of usage on the current concrete structure. There are processed results of measurement on the testing samples which will be compared with results of stress strength. There is also spoken about calibration relationships in the bachelor’s thesis. Calibration relationships are described in Czech technical norms.
Possibilities of using GPR to detect reinforcement of concrete structures
Filipu, Martina ; Heřmánková, Věra (referee) ; Anton, Ondřej (advisor)
The aim of this study is to outline how is GPR used to detect reinforcement in concrete structures. In each part the study deals with diagnostic testing methods used for building construction and shows a recognisability of steel reinforcement in concrete. Then it closely examines applications of GPR in a diagnostics of reinforced concrete structures with using Hilti PS 1000 device. In the practical part I conducted a building survey of wall silo using GPR and electromagnetic indicators. The aim was to identify the position of reinforcement which was subsequently compared with the project documentation. The construction survey was carried out as a reason of several serious defects such as cracks and tilting of major part of one of the silo walls.
The Influence of Specimen Size on the Values of Material Characteristics Determined using the Resonance Testing
Čaněk, Michal ; Cikrle, Petr (referee) ; Kocáb, Dalibor (advisor)
The bachelor's thesis deals with influence of specimen size on the values of material characteristics determined using the resonance testing. Different sizes and shapes of specimen made from two different concretes were tested in the experiment. The specimens were tested to determine the dynamic material characteristics (especially dynamic modulus of elasticity). The results were summarized in tabular and graphical form and were examined by simple statistical analysis to determine resulting conclusions.
Survey and Diagnostics of Reinforced Concrete Structure
Filipu, Martina ; Heřmánková, Věra (referee) ; Anton, Ondřej (advisor)
The master´s thesis deals with concrete properties and it introduces problematics of building survey. In each part the study deals with diagnostic methods used for building construction. Then it closely examines selected methods, which are used for recognisability of steel reinforcement in concrete. In the practical part I conducted two engineering surveys of reinforced concrete industrial buildings. The main aims were to identify the position of reinforcement in selected elements of crane runway and to evaluate the quality of used concrete. The last part of thesis is focused on static assessment of short corbel of crane runway.
The comparison of testing methods using for determining the frost resistance of concrete
Kněbort, David ; Vymazal, Tomáš (referee) ; Kocáb, Dalibor (advisor)
The diploma thesis deals with the possibilities of evaluating the degradation of mechanical resistance of non-air-entrained concrete in the structure by frost cycles. The first part is focused on concrete, its resistance and test methods. This is followed by the definition of frost resistance, the effects of freeze-thaw on concrete at all stages of its service life and the possibilities of determining freeze-thaw resistance according to current standards. It describes in more detail selected test methods for determining frost resistance. In the practical part, it focuses on the determination of degradation resistance of test specimens made in molds and taken from the structure using reference and non-reference methods. In conclusion, it compares the different test methods and their suitability for the determination of freeze-thaw resistance.
Diagnostics and assessment of the structure of bridge
Lehocký, Peter ; Komárková, Tereza (referee) ; Kocáb, Dalibor (advisor)
This diploma thesis focuses on diagnostics of bridge structures. First part of this diploma thesis will focus on theoretical knowledge about bridge structures and common diagnostic techniques suited for examining material priperties of samples taken from structure. Second part of this thesis will focus on practical use of experiments used in diagnostic branch. I will be doing visual observation of concrete structure followed by experiments on core samples. End of thesis will be evaluating structure from global perspective and will deliver specific sugestions for renovation.
Experimental determination of the relationship between NDT parameters and the compressive strength of concrete
Kozáček, Vojtěch ; Komárková, Tereza (referee) ; Kocáb, Dalibor (advisor)
The diploma thesis deals with non-destructive testing of concrete as well as with the relationship between determined parameters and the compressive strength of concrete. The thesis is mainly focused on the ultrasonic pulse velocity method and the rebound hammer test. The experimental part of the thesis describes non-destructive tests performed on concrete blocks. The compressive strength was tested on the drill cores taken from the concrete blocks. The aim of this thesis is to find regression models of the relationship between the compressive strength and non-destructive parameters, and the subsequent analysis of the results.

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