Monitoring stress related velocity variation in concrete with a $2.10^{-5}$ relative resolution using diffuse ultrasound.

Éric Larose (1) , Stephen A. Hall (2)

1 LGIT - Laboratoire de Géophysique Interne et Tectonophysique
2 3SR - Laboratoire sols, solides, structures - risques [Grenoble]

Ultrasonic waves propagating in solids have stress-dependent velocities. The relation between stress (or strain) and velocity forms the basis of non-linear acoustics. In homogeneous solids, conventional time-of-flight techniques have measured this dependence with spectacular precision. In heterogeneous media like concrete, the direct (ballistic) wave around 500~kHz is strongly attenuated and conventional techniques are less efficient. In this manuscript, the effect of weak stress changes on the late arrivals constituting the acoustic diffuse coda is tracked. A resolution of $2.10^{-5}$ in relative velocity change is attained which corresponds to a sensitivity to stress change of better than 50 kPa. Therefore the technique described here provides an original way to measure the non-linear parameter with stress variations on the order of tens of kPa.

Domaines: Acoustique [physics.class-ph]; Acoustique [physics.class-ph]; Matériaux

Éric Larose, Stephen A. Hall. Monitoring stress related velocity variation in concrete with a $2.10^{-5}$ relative resolution using diffuse ultrasound.. Journal of the Acoustical Society of America, 2009, 125 (4), pp.1853-1856. ⟨hal-00352370v2⟩