Application of new ultrasound and sound generation methods for testing concrete structures

Transient stress waves offer a powerful approach for non-destructive condit ion evaluation of concrete structures. However, currently used stress-wave- generating techniques are limited by poor controllability and/or penetratin g ability. Stress wave generation must therefore be improved so that the ap plication of existing and new ultrasonic and sonic non-destructive testing techniques to concrete structures will be more effective. This paper first summarizes the existing, traditional stress-wave-generating techniques for testing concrete structures. A method by which electromagnetic and piezoele ctric-based sources are driven by AM burst signals is then introduced, full y detailed and shown to be appropriate for concrete tests in place of tradi tional sources. The performance of these sources is demonstrated through th e results of impact-echo tests and spectral analysis of surface waves perfo rmed on a Portland cement concrete structure.