Acoustic Emission Assessment of Corroded RC Columns Jointly Reinforced with Concrete Canvas and CFRP

To explore the crack behaviors of corroded concrete columns jointly reinforced by concrete canvas (CC) and carbon fiber reinforced polymer (CFRP), a total of six specimen sets with different reinforcement forms and corrosion rates are designed and tested by acoustic emission (AE) technology. The assessed methods are AE characteristic parameters, RA-AF values, b values, and AE event spatial location map. The results show that the presence of CC changes the failure morphology of the specimen and improves the uneven deformation of concrete in the core area, which proves that the jointly reinforced method exhibits high plasticity deformation ability. The crack mode of the jointly reinforced specimen undergoes multiple transformations between tensile cracks and shear cracks, before ending in the final crush failure. The fluctuations in both amplitude and frequency of the b values of the jointly reinforced specimens increase significantly with time. The crack activity of concrete is more intense in this period, which proves that the jointly reinforced method ensures a more complete failure. Moreover, the increases in corrosion rate reduced the probability of shear cracks in the core concrete and further increased the failure degree of the specimen. The present study demonstrated that AE monitoring can effectively capture the characteristics of the cracking process of jointly reinforced concrete.