• Karaiskos, Grigorios
• Deraemaeker, Arnaud
• Van Hemelrijck, Danny
• Aggelis, Dimitrios G.
• Tsangouri, Eleni

Abstract

In the presence of crack discontinuity into concrete, the accuracy of Acoustic Emission (AE) source location is significantly decreased. The previous research done in literature concerning concrete fracture evaluation by using AE considers inaccurate the detection of Acoustic Emission as soon as cracks widen and<br/>macro-fracture occurs. In this study, the loss of accuracy of AE source location and subsequently the emitted wave degradation due to concrete fracture is quantified by combining AE and ultrasound pulse technique. In detail, a low-cost and aggregatesize piezoelectric PZT (i.e. lead-zirconate-titatnate) transducer is embedded into concrete and transmits ultrasonic waves that travel through concrete. In the present study, a group of AE sensors are placed on concrete surface and locate both spatially and chronically the wave source. It is shown that, under a small-scale, three-point bending load test, a unique crack forms and propagates in concrete and as a consequence, the location of embedded PZT transducer by AE sensors loses its accuracy with a three-dimensional (3D) spatial error greater than 10% (since the PZT transducer stands next to the crack). Additionally, the crack sealing by means of autonomous healing processes (filling of the crack void with adhesive agent) corrects the AE location of the PZT transducer (the spatial error is diminished to 4%).The study aims to develop a method to quantitatively evaluate the loss of AE source location accuracy in concrete structures relatively to the damage evolution.<br/>

Topics

• impedance spectroscopy
• surface
• crack
• ultrasonic
• acoustic emission
• void