Y.-X. Zhang1, O. Abraham1, E. Larose2, T. Planes2, A. Le Duff3, B. Lascoup4, V. Tournat5, R. El Guerjouma5,
L.-M Cottineau1, O. Durand1.
In 37th Annual Review of Progress in Quantitative Nondestructive Evaluation, San Diego – USA, juillet 2010.
The determination of the stress level in in situ concrete structures is of paramount importance for the engineers. CODA wave interferometry (CWI) has been recently propose to monitor non destructively stress level in pre-stress concrete structures. The idea is to follow very small change of the ultrasonic wave velocity linked to stress level modifications through Murnaghan’s theory. The velocity change which is of the order of 0.1 % for 10 MPa for classical concrete can be measured taking advantage of the heterogeneity of concrete. Indeed multiple scattering generated by a source generating a wave train having wavelengths sizes comparable to that of aggregates will make possible travel time delay measurement with sufficient accuracy in case of small modification of the medium mechanical properties. An experiment on a real size concrete structure submitted to time varying loading is commented.
1 MACS Department, LCPC, BP4129, 44341 Bouguenais Cedex, France
2 LGIT, Grenoble, France
3 GSII, ESEO, BP30629, 49009Angers, France
4 ESTACA, Laval, France
5 LAUM, Le Mans, France