ACOUSTIC EMISSION MONITORING OF TEXTILE REINFORCED CEMENT PLATES

Acoustic emission (AE) is commonly applied in laboratory and in-situ for structural condition evaluation of materials. Its advantages concern the non-invasive and safe application, while the developments in sensors’ technology and signal analysis, make it a suitable technique for monitoring of the structural condition. Concerning cementitious composite plates, AE parameters have proven its potential to characterize not only the fracture mode but also the developing strain field before visible damage evolves. Matrix cracking events are recorded as relatively short elastic signals occupying high frequencies while debonding between layers or fiber pull-out result in longer signals with lower frequency content. However, the capacity of the technique is not fully exploited in-situ mainly because of factors that mask the original source information. Wave propagation distance and exact path, reflections, dispersion due to plate geometry and heterogeneity usually result in attenuating the signal and elongating it in time domain. These factors change the received AE waveform and therefore, may complicate the evaluation outside laboratory where the sample dimensions are usually larger. In this study, textile reinforced cement plates with different widths and curvatures are loaded in bending with concurrent AE monitoring. The aim is to evaluate the influence of the geometry in order to check if conclusions based on laboratory small straight specimens can be upgraded to larger scales and different geometries.