TY - EJOU AU - Chen, Ruoyu AU - Li, Da AU - Li, Jian AU - Yan, Yitian AU - Zhan, Qiwei AU - Ai, Li TI - Ultrasonic Shear-Wave Inversion for Characterizing Corrosion-Induced Rebar–Concrete Interfacial Debonding T2 - Structural Durability \& Health Monitoring PY - VL - IS - SN - 1930-2991 AB - The structural performance of reinforced concrete critically depends on the integrity of the bond at the rebar–concrete interface. Reliable nondestructive evaluation (NDE) methods capable of assessing interfacial degradation remain limited, particularly when conventional ultrasonic imaging techniques fail to resolve subtle bond deterioration. This study presents a parameter-based ultrasonic evaluation approach based on shear-wave full-waveform inversion (SH-FWI) for characterizing rebar–concrete interfacial degradation. Ultrasonic shear-wave measurements acquired using a commercial array system (A1040 MIRA) were processed through a two-dimensional SH-wave inversion framework to reconstruct spatial distributions of shear-wave velocity and density within concrete. Unlike conventional amplitude-based imaging methods, the proposed approach provides parameter-based representations of material properties, enabling the identification of mechanically degraded interfacial regions through measurable physical contrasts. Three-dimensional visualizations derived from the inverted parameter fields further enhance the interpretation of interfacial conditions. The method was experimentally validated using a reinforced concrete specimen containing two embedded rebars: one maintained in an intact state and the other subjected to electrically accelerated corrosion to induce bond degradation. The inversion results revealed distinct low-velocity and density-anomaly zones surrounding the corroded rebar. The average inverted density of the intact rebar was approximately 4500 kg/m3, whereas the density in the corroded zone dropped below 1000 kg/m3, consistent with the presence of corrosion-induced interfacial deterioration. In contrast, conventional Synthetic Aperture Focusing Technique (SAFT) imaging showed limited capability in differentiating degraded and intact interfaces. The results demonstrate that shear-wave inversion enables parameter-based ultrasonic evaluation of rebar–concrete bond condition and offers improved sensitivity to interfacial degradation compared with traditional ultrasonic imaging approaches. KW - Concrete inspection; inversion method; rebar debonding; ultrasonic FWI; SH- and Love-waves DO - 10.32604/sdhm.2026.084669