Conditioning and elastic nonlinearity in concrete: Separation of damping and phase contributions

Elastic properties of concrete are affected, already at low strains, by its nonlinear properties, which are very sensitive to the presence of microcracks and hence to progression of damage. Conditioning and memory effects, which are both nonlinear effects are also manifested in intact samples and understanding their role in the definition of the propagation of elastic waves is crucial for the development of techniques aiming to quantify the nonlinear response and extract information about the microstructure of concrete specimens or concrete-based structures. Results are presented here to make evident the possibility to experimentally detecting and comparing the nonlinearity and conditioning induced by elastic modulus and damping nonlinearities in different concrete samples.