Acoustic Transmission Technique for Evaluating Fatigue Damage in Concrete Bridge Deck Slabs

Abstract

This paper focuses on evaluation of a novel acoustic transmission technique (ATT) for tracking fatigue-induced damage in steel-free bridge deck slabs under lab conditions. The technique comprises identification of changes in acoustic waveform attenuation through concrete by comparing integrated waveform amplitudes recorded at 2+ acoustic sensors. This methodology is based on the experimental observation that cracking in concrete leads to increases in attenuation of the acoustic signals. The mapping of cracks and other means of detecting damage induced by cracks were used to independently verify the conclusions from the ATT. Each of 4 deck slab panels was subjected to ~1,700 cycles of a heavy wheel load; damage induced was tracked reliably by the ATT. The procedure of evaluating dimensionless integrated amplitude ratios in lieu of absolute signal magnitudes proved a highly robust, stable means of measuring attenuation, hence damage in the slab.