Acoustic Emission Monitoring of Reinforced Concrete under Accelerated Corrosion

The development of techniques capable of evaluating the deterioration of reinforced concrete structures is instrumental to the advancement of structural health monitoring (SHM) techniques and service life estimate methodologies for constructed facilities. One of the main causes of degradation is the corrosion of steel reinforcement. This process can be modeled phenomenologically, whereas laboratory tests aimed at studying durability responses are typically accelerated to provide usable results within a realistic period of time. Numerous nondestructive methods have been recently studied. Acoustic emission (AE) is emerging as a nondestructive tool to detect the onset and progression of deterioration mechanisms associated with concrete cracking. In this paper, an accelerated corrosion and continuous AE monitoring test setup is presented, providing relevant information on the characteristics of the corrosion circuit, continuous measurement procedure, selection of AE sensors, and AE parameter setting for data acquisition. The effectiveness of AE in detecting and characterizing the initiation of the corrosion process is discussed on the basis of results from small-scale, precracked RC specimens that are representative of areas near the clear cover in typical RC members. The main outcome is a new approach of AE data interpretation based on time-driven parameters.