Recommendation of RILEM TC 269-IAM: damage assessment in consideration of repair/retrofit-recovery in concrete and masonry structures by means of innovative NDT

This recommendation specifies a method for measuring passive elastic waves and assessing damage to concrete members such as decks and girders. To visualize internal damage, acoustic emissions (AE) and elastic wave velocity are employed. Firstly, based on the data detected by AE sensors, the location of the AE sources is estimated. Then, the velocity distribution in the concrete is evaluated. Accordingly, the internal damage of concrete deck can be evaluated quantitatively by applying a simple procedure using two evaluation axes, which are AE source density and elastic wave velocity in the concrete. Thus, the local deterioration of the concrete member can be classified into several stages that represent the damage levels of internal defects.