LAUSR

The second harmonic generation (SHG) of nonlinear Rayleigh waves is applied to characterize the damage state induced by alkali-silica reaction (ASR) in large-scale plain concrete slabs. A measurement setup that uses a wedge transmitter and a non-contact, air-coupled receiver is implemented to generate and detect nonlinear Rayleigh surface waves and to obtain both the linear and nonlinear acoustic parameters, while complementary measurements track expansion of the concrete slabs. These results demonstrate the potential of SHG using nonlinear Rayleigh waves to assess the evolution of microscale damage induced by ASR in large-scale, in-service concrete components.