Determination of nonlinear elastic constants and stress monitoring in concrete by coda waves analysis

Abstract

ABSTRACT For non destructive stress evaluation in prestressed concrete, we describe in this paper a promising ultrasonic method. In “ordinary” isotropic homogeneous materials such as steel, ultrasonic determination of third order elastic constants provides means for stress evaluation since half a century. In case of concrete, example of a class of materials that exhibit strong multiple scattering as well as significant elastic nonlinear response, accurate velocity monitoring is challenging. In this paper, we purpose a novel method originally from geophysics. So called “coda wave interferometry” (CWI), this technique is transposed to concrete. We show that intense scattering can be applied to robustly determine velocity changes and so, nonlinear elastic constants. In addition, we show how this method could be transposed in case of in situ measurements in concrete structures and outline future possible applications.