The sensitivity of the acoustic emissions to the stress field and steel reinforcement in beams under monotonically increased load

Abstract

An experimental study on the sensitivity of the Acoustic Emissions (AE) to the stress field and steel reinforcement in concrete beams is reported in this article. The Reinforced Concrete (RC) beam specimens were tested under a monotonically increasing load in the laboratory. Three large RC beams with shear reinforcement and another two large RC beams without shear reinforcement were tested. The aim is to study the sensitivity of the AE to the stress field and the steel reinforcement. Gaussian Mixture Modelling (GMM) algorithm of AE was implemented for the crack classification in the RC beams. Further, sifted b-values were used to improve the interpretation of the conventional b-value analysis. AE generated during tensile cracking and shear cracking were compared with the AE based sifted b-values for RC beams with shear reinforcement and RC beams without shear reinforcement. The AE based sifted b-values, which reflects the extent of the fracture process, decreased with the increase in mid-span deflection. When the generation of AE related to tensile cracks was less, the sifted b-values decreased gradually. In the shear failure beam, the AE related to shear cracks constituted a higher percentage of total hits, and sifted b-values sharply decreased. The observations may provide a reference for the studies related to AE testing of RC structural members.