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Ultrasonic testing of fresh cementitious materials using a mode conversion technique

Experimental and numerical results
Ultraschallprüfung frischer Zementwerkstoffe mittels Wellenumwandlungsmethode. Experimentelle und numerische Ergebnisse
 
: Bouhadjera, A.; Schubert, F.

Deutsche Gesellschaft für Zerstörungsfreie Prüfung e.V. -DGZfP-, Berlin:
Advanced testing of fresh cementitious materials. CD-ROM : August 3 - 4, 2006, Stuttgart, Germany
Berlin: DGZfP, 2006 (DGZfP Proceedings BB 102)
ISBN: 3-931381-85-4
Lecture 28
Workshop "Advanced Testing of Fresh Cementitious Materials" <2006, Suttgart>
English
Conference Paper
Fraunhofer IZFP, Institutsteil Dresden ( IKTS-MD) ()
zerstörungsfreie Prüfung; akustisches Messen; Schallgeschwindigkeitsmessung; Wellenumwandlung; Zementpaste; Wasserabbinden von Zement; Transversalwelle; Longitudinalwelle; Elastizitätskonstante; Optimierung

Abstract
A new technique for testing fresh cementitious materials is described. It enables the measurement of both compressional and shear wave speeds within prismshaped cement based samples using just one transducer. This leads to the evaluation of second order elastic constants that can be correlated with material properties. Moreover, attenuation and porosity can be determined with the same apparatus. Some cement and mortar samples were tested over a period of one month and variation of wave velocity was measured. Early results showed that it is possible to improve the system by choosing the right parameters, such as transducer frequency, the focusing of the ultrasonic beam, and the size of the specimen. Thus, in order to optimize the technique a simulation program based on the elastodynamic finite integration technique (EFIT) was used. Numerical and experimental results reveal that the proposed apparatus is easy to use, robust and leads to the determination of different material parameters.
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: http://publica.fraunhofer.de/documents/N-84613.html