Damage evaluation and corrosion detection in concrete by acoustic emission

Acoustic emission (AE) techniques have been extensively studied and applied to nondestructive testings (NDT) of concrete and concrete structures. For damage evaluation, AE behavior of concrete under compression could be analyzed, applying the rate process theory. Based on Loland's model in damage mechanics, a relation between AE rate and the damage parameter is correlated. By quantifying intact moduli of elasticity of concrete from the database on the relationship, relative damages of concrete in existing structures are successfully estimated by the compression test of concrete samples. The technique is applied to estimate concrete samples of recycled aggregate. The deteriorated degree of recycled concrete is reasonably estimated. For corrosion detection, continuous monitoring of AE signals is useful for earlier warning of corrosion in reinforcement. It is demonstrated that the onset of corrosion in reinforcement and the nucleation of corrosion cracking in concrete could be clearly identified by AE parameter analysis.