Abstract
Since the number of existing concrete structures increases, repairing of existing concrete structures is in great demand. In addition, a tight bonding between existing concrete and repairing material is necessary for a successful repairing of concrete structure. As for shear bonding strength test, it is difficult to evaluate accuracy shear bonding strength, because complex failure process occurs in shear bonding strength test. Damage process in concrete can be investigated by acoustic emission (AE) method which is one of non destructive evaluation (NDE) techniques. Furthermore, damaged area and crack type of AE source in concrete are identified by results of SiGMA (simplified Green's functions for moment tensor analysis) procedure. In this study, in order to evaluate shear bonding strength between substrate concrete and repairing material, bi-surface shear test was carried out in a laboratory. In the experiment, the interface in substrate concrete was treated three different roughnesses of highly rough, medium in roughness and without treatment to investigate effects of roughness of the interface on shear bonding strength. Obtained AE signals were applied to SiGMA analysis. As a result, the shear bonding strength varied with roughness of the interface in substrate concrete. In addition, failure process and failure mechanisms in the bi-surface shear test were estimated by AE-SiGMA analysis. In high shear bonding strength, a lot of AE sources located at the interface were identified as shear cracks, while tensile cracks generated in bending span under the bi-surface shear test.
