Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Features for ultrasonic imaging of concrete elements. Phase evaluation and air coupled ultrasound
It is an important subject of research to develop and validate fast and reliable methods for imaging the inner structure of post-tensioned concrete elements. For this ultrasonic imaging systems and modelling ultrasonic wave propagation were much ameliorated in recent years. A new possibility of ultrasonic imaging is to consider the phase information of the reflected ultrasonic signal. Applying this method, the reconstruction calculation allows the distinction, if a reflector is metallic, or if the reflection is caused by an air inclusion. This has important relevance for the localisation of grouting faults in posttensioned concrete structures. There are several examples, which prove that ultrasonic reflections from the top side of the tendon duct can be distinguished from those from the interior of the tendon duct. A question not yet completely solved is the origin of signals assigned to bottom side reflections and scatter of the tendon duct. In order to solve this question new concrete elements with artificial grouting faults have been constructed and investigated. Some results are presented in the paper. In order to speed up ultrasonic echo measurements, air coupled transducers can be used. It has been shown that ultrasonic echo measurements of 20 cm thick concrete slabs can be carried out with air coupled ultrasonic transducers in the frequency range of 100 kHz. In applying a scanning unit it becomes realistic to image the inner structure of concrete elements with high scanning speed. In the 2nd part of the paper examples of testing measurements are presented applying reconstruction calculation.
Features for ultrasonic imaging of concrete elements. Phase evaluation and air coupled ultrasound
It is an important subject of research to develop and validate fast and reliable methods for imaging the inner structure of post-tensioned concrete elements. For this ultrasonic imaging systems and modelling ultrasonic wave propagation were much ameliorated in recent years. A new possibility of ultrasonic imaging is to consider the phase information of the reflected ultrasonic signal. Applying this method, the reconstruction calculation allows the distinction, if a reflector is metallic, or if the reflection is caused by an air inclusion. This has important relevance for the localisation of grouting faults in posttensioned concrete structures. There are several examples, which prove that ultrasonic reflections from the top side of the tendon duct can be distinguished from those from the interior of the tendon duct. A question not yet completely solved is the origin of signals assigned to bottom side reflections and scatter of the tendon duct. In order to solve this question new concrete elements with artificial grouting faults have been constructed and investigated. Some results are presented in the paper. In order to speed up ultrasonic echo measurements, air coupled transducers can be used. It has been shown that ultrasonic echo measurements of 20 cm thick concrete slabs can be carried out with air coupled ultrasonic transducers in the frequency range of 100 kHz. In applying a scanning unit it becomes realistic to image the inner structure of concrete elements with high scanning speed. In the 2nd part of the paper examples of testing measurements are presented applying reconstruction calculation.
Features for ultrasonic imaging of concrete elements. Phase evaluation and air coupled ultrasound
Leistungsmerkmale zu Ultraschallabbildung von Betonelementen. Phasenauswertung und Luft angekoppelter Ultraschall
Krause, M. (Autor:in) / Milmann, B. (Autor:in) / Mayer, K. (Autor:in) / Gräfe, B. (Autor:in)
2008
9 Seiten, 12 Bilder, 15 Quellen
(nicht paginiert)
Aufsatz (Konferenz)
Datenträger
Englisch
New Possibilities for Ultrasonic Imaging of Concrete Elements
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Basic investigation with air-coupled ultrasonic echo for concrete elements
| Tema Archiv | 2006
New examples for ultrasonic imaging of prestressed concrete elements
| British Library Conference Proceedings | 2008
| British Library Online Contents | 2003