Evaluation of deterioration in reinforced concrete structures by AE technique

Abstract

Acoustic 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.

Intensity Analysis Method for Measurement the Damage Severity of Concrete Structure by Utilizing the Acoustic Emission Technique

“…Referring to these figures, there is a rapid increase in the slope of the CSS curve within intervals of 1000 -2000s and at the final stage of the testing within 2500 -3000s. These outcomes are almost similar to the previous research work by [17]. Throughout the time of interval, the values of HI are highly peak correspond to the slope increase of the CSS curve value.…”

“…These ranges of values are similar with the previous research and this signifies the release of the high energy content in the beam specimens, where as the damages are continuously being more serious till to failure stage such as breakage of the concrete structure and shear failure [17].…”

“…Throughout the time of interval, the values of HI are highly peak correspond to the slope increase of the CSS curve value. Upon to that matter, the previous research has discussed that peaks of HI and CSS curve can be employed to discriminate and identify the possible damaged mechanism and onset of failure [14], [17].…”

Impacts of Cyclic Loading and Unloading Rates on Acoustic Emission Evolution and Felicity Effect of Instable Rock Mass

“…e accumulated internal energy releases suddenly in the form of elastic waves, thus resulting in the AE phenomenon. Scholars have made abundant researches on rock AE characteristics during the deformation and failure process [4][5][6][7]. Lavrov [8] observed the Kaiser effect in a brittle limestone cyclically loaded with different loading rates and found that damage formed in rock at a high loading rate can hardly be revealed by reloading with slow rate, yet the damage formed during loading with slow rate can be successfully revealed by using fast reloading.…”

Fluorescence based fibre optic pH sensor for the pH 10–13 range suitable for corrosion monitoring in concrete structures

“…The structures of reinforced concrete are usually exposed to a wide variety of damaging influences that leads to reduction in the strength, utility and aesthetic quality of structures [1,2]. Aside from mechanical stress, corrosion due to chemical and environmental attacks is one of the most damaging processes in concrete [3][4][5] causing great concern for civil and structural engineers.…”