Fracture monitoring of steel and GFRP reinforced concrete beams using acoustic emission and digital image correlation techniques

Abstract

AbstractIn this work, fracture monitoring of steel and GFRP bars reinforced concrete beams in flexure is investigated by using non‐destructive acoustic emission (AE) and digital image correlation (DIC) techniques. The combined methodology provides complementary information from 'the ear' aided by the AE and from 'the eye' aided by the DIC. AE waveform parameters of the number of AE hits and their amplitudes, cumulative signal strength (CSS), average frequency, and rise‐time successfully pick‐up the divergent cracking initiation and fracture progression in steel‐reinforced concrete (RC) and GFRP‐RC beams. AE‐XY plots and longitudinal strain profiles obtained from DIC give an early, online, and real‐time representation of progressive AE activity and strains inside concrete much before it is visible to the naked eye. AE in conjunction with DIC was able to efficaciously depict the micro‐and‐macro cracks evolution and their advancement in steel‐RC and GFRP‐RC at various stages of loading Moreover, DIC identified critical damage areas as a function of loading periods, while AE was capable of monitoring the damage process and revealed changes in the overall behavior. It is successfully demonstrated that combined AE and DIC monitoring can enhance non‐destructive monitoring skills in RC structures involving widely different steel and GFRP bars as reinforcements and depict efficaciously their fracture/cracking behavior.