A review of acoustic emission as indicator of reinforcement effectiveness in concrete and cementitious composites

This review focuses on the fiber reinforced cementitious composites for construction, a rapidly advancing material field, from a certain perspective. While fiber reinforcement is known to dominate the cracking and post-cracking response, it seems unambiguous that the fiber influence is also seen at the pre-peak behavior through the restrain they cause to cracking. Acoustic Emission (AE) is often selected to track the transition from solid to damaged state and provide damage assessment on concrete and cementitious composites. However, the sensitivity of AE allows to characterize not only large-scale fracture phenomena but also events in the micro-scale which give no other indication. Herein, information from relevant papers is gathered showing that AE features show strong sensitivity to the shear transfer mechanism between fibers, rebars or patches and matrix, considerably earlier than the visible damage. It is consistently shown that as the quality, quantity or effectiveness of the reinforcement increases, this is reflected on the AE behavior of the early part of the loading, allowing for comparison between different type of reinforcements and prediction on the final mechanical capacity.