Concrete Specimens under Four-Point Bending: Correlation Between Acoustic Emission Signals and Modal Frequency Variation

In this study, the Acoustic Emission and Dynamic Identification techniques are applied to examine the stress dependent damage progress during four-point bending tests on pre-notched concrete beams. The damage mechanisms were characterized considering the AE signals obtained during the tests by increasing the vertical deflection. In particular, the dominant fracture mode was identified, and the correlations between dissipated and emitted energies were investigated. Moreover, the variations in the natural bending frequencies produced by the crack advancement under loading were detected.