Evaluation of deterioration in reinforced concrete structures by AE technique

Abstract

AbstractAcoustic emission (AE) technique is gaining increasing interest for applications in civil engineering. AE indeed is a passive nonintrusive technique that can be applicable either in structural health monitoring (global evaluation) and in defect localization (local evaluation). The most promising application of such a technique seems to be however in the evaluation of growing defects. Defects such as cracks and delamination can be caused by reinforcement corrosion as well as by other concrete deterioration mechanisms (alkali silica reaction, sulphate attack, etc.) as well as originating from improper concrete casting, curing or structure setting. Damage severity can be evaluated by means of the intensity analysis (IA) through the use of different indexes such as ‘Load Ratio’, ‘Calm Ratio’, ‘Felicity Ratio’ or ‘Historical Index’. Damage evolution analysis along time could be however significantly improved by adopting some procedure already used in the field of geophysics and earth science. Among various parameters, the most significant one is the b‐value which is derived from the amplitude distribution data of AE following the methods used in seismology. Several application examples applied to prestressed concrete structures are reported in the paper.