Use of acoustic emission to characterize matrix cracking and interlaminar shear in textile reinforced mortars

This paper presents the results of acoustic emission (AE) monitoring during fracture of textile reinforced
inorganic phosphate cement (IPC) beams. The setup is based on three point bending with variable bottom
span in order to control the dominant fracture mechanism from matrix cracking to interlaminar shear.
The damage developed by the different stress fields is adequately monitored by AE and specifically by waveform parameters like duration, frequency content and energy. The AE parameters enable classification of the waveform according to their origin and shed light to the dominant stress field. In order to check the effect of elastic wave propagation, fracture mode classification is attempted not only by the whole population of AE data, but also separately by sensors at different distances from the center of the specimen. It is shown that the boundaries between matrix cracking and debonding/pull-out events strongly depend on the acoustic signal propagation path in this heterogeneous, laminated, plate structure. Ways to compensate for the effect of wave attenuation and distortion are discussed. Information about the load at the onset of damage and the dominant mode can give valuable input to numerical models for predicting the mechanical and fracture behavior of the TRC structures.