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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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Properties of cementitious matrix in the environment of radioactive waste respositories
Podojil, Adam ; Jelínek, Emil (advisor) ; Kozlovcev, Petr (referee)
Cementitious materials will serve as a construction and filler material for the construction of a deep repository of radioactive waste. Therefore, three different materials represented by four samples were studied in the present work. This is CEM II AS 42,5R cement commercially available in Čížkovice, cement CEM III B / 32,5 SV with ash and aggregate used as filler concrete for storage chambers from radioactive waste repository Richard and cement CEM I 42, 5 with fine and coarseraggregate used for fixed radioactive waste (RAW) in Velké Zbytky in the area of ÚJV Řež,as Chemical (silicate analysis) and phase composition (XRD powder diffraction analysis) were determined in the studied materials. Further, the orientation strength of the monolithic samples and their mutual comparison (compression strength measurement) were determined. Percolation leaching experiments were carried out, three columns with CEMII, RICHARD and ÚJV samples were run. The conditions of the experiments were chosen to approach the conditions in the rock environment of a possible deep radioactive waste repository. Synthetic granite water (SGW) was used as the leaching solution. In all column experiments, attempts to observe changesin the concentrations of selectedindicators (Na+ , K+ , OH- ,Ca2+ ,pH, Conductivity, SiO2, Mg2+ and...
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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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