An optical correlation technique for characterizing the crack velocity in concrete
Laboratoire d’Étude des Microstructures et de Mécanique des Matériaux (LEM3), Lorraine University, Ile du Saulcy, 57045 Metz Cedex 1, France
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Revised: 13 March 2012
Published online: 7 May 2012
In the present work, an experimental method named “the rocking spalling test” is proposed to investigate the crack-propagation velocity in concrete and rock-like materials under dynamic tensile loading. This method is based on the use of double-notched specimens loaded in spalling tests. A compressive pulse is transmitted to a rectangular specimen by means of a Hopkinson bar. It is reflected as a tensile wave on the opposite free surface of the sample. A large notch provides a rocking effect of the rear part of the specimen whereas a short notch is used to trigger a single unstable crack. This experimental configuration has been optimized through a series of numerical simulations. Finally, a series of tests have been conducted on dry and wet concrete specimens. Crack gauges and ultra-high speed camera coupled to Digital Image Correlation have been used to characterize the crack speed in dry and wet concrete samples.
© EDP Sciences, Springer-Verlag, 2012