Nonlinear Ultrasonic Evaluation of Concrete Microcracking

Microcracking is usually associated with most types of concrete deterioration. The nondestructive detection of deterioration in in‐situ concrete in its early stages is not practical using current technology. In this project nonlinear ultrasound was used to evaluate the degree of microcracking changes resulting from increasing compression stresses. Second and third harmonic amplitudes were measured and correlated to the degree of microcracking induced in the specimen. These harmonics were found to increase with increasing levels of microcracking.