Damage detection of ultra-high-performance fibre-reinforced concrete using a harmonic wave modulation technique

Abstract

In this paper, a damage detection technique, named cross-modulated vibro-acoustic (CMVA) technique, is proposed to detect damages induced by flexural loading in ultra-high-performance fibre-reinforced concrete (UHP-FRC) material. Different from conventional vibro-acoustic methods, the pump wave of the proposed CMVA technique is modulated by two low-frequency waves to address limitations of pump wave generator on excitation frequency. The proposed technique has lower power consumption and high sensitivity to micro-damages. In this study, a mechanical model of contact nonlinearity at interfaces is developed to establish the nonlinear parameter Dα for the proposed CMVA technique in describing various flexural damage levels. The conventional resonant frequency (RF) test based on ASTM C215-02, is conducted to compare with the results of the proposed CMVA technique. This study presents the application of the proposed CMVA technique to monitor the damage evolution the UHP-FRC structure. The experimental results show that the sensitivity of Dα to early-stage damages and material degradation is much higher than the conventional measurement of RF test. Therefore, the proposed CMVA technique is an accurate and reliable technique to monitor progressive damages in structures.