Experimental study on acoustic emission characteristics of different bonding interfaces in steel-concrete composite beams

In order to investigate the propagation characteristics of acoustic emission (AE) signals through steel-concrete interface and NC-UHPC bonding interface, lead-breaking simulation tests were carried out at different locations of a steel-concrete composite beam structure composed of an I-beam and a NC-UHPC composite plate. The attenuation characteristics of AE signals were studied through parameter analysis. AE signal propagation analysis shows that various characteristics including the attenuation of energy, amplitude and impact counts changes when AE signal propagates through different bonding interfaces. When AE signal propagates at the bonding interface between NC and UHPC concrete, amplitude attenuation is relatively small, impact count is next, and energy attenuation is large. The attenuation of the signal from NC to UHPC is slightly higher than that from UHPC to NC concrete. When the signal propagates at the bonding interface between steel plate and NC, energy attenuation is relatively large, impact count is next, and amplitude attenuation is small. The attenuation of signal from steel plate to NC is slightly higher than that of signal from NC to steel plate through bonding interface. Amplitude parameters have good correlation with source signals. The test results provide a useful reference for evaluating the damage of steel-concrete composite structures by using AE parameters.