NON-DESTRUCTIVE CHARACTERIZATION OF NON-LINEAR ELASTIC BEHAVIOR OF CONCRETE: POTENTIAL, LIMITATIONS AND PROSPECTS

Abstract

The potential of nonlinear acoustics indicators for con-crete NDE is established. Their large sensitivity has beenshown regarding damage and some pathology for years.The physics of nonlinearity is introduced; experimentalmeans to measure such parameters are presented as wellas associated limitations. Qualitative results obtained inthe presence of pathologies, varying water saturation,varying porosity or damage are presented. We introduce aquantitative method to measure nonlinear parameters bynonlinear resonance (global) measurements. Then a newmethod founded on time reversal is presented. This princi-ple allows non-contact local measurements at variousdepths. It is validated in the presence of thermal damage.