Development of ultrasonic model-based iterative reconstruction technique for concrete structures with corroded rebars

Area of Science:

• Civil Engineering
• Materials Science
• Non-Destructive Testing

Background:

• Structural health monitoring (SHM) faces challenges in detecting rebar corrosion in concrete due to complex wave propagation and signal clutter.
• Conventional ultrasonic imaging methods struggle with limited contrast and high background interference, hindering early damage detection.

Purpose of the Study:

• To introduce a novel reconstruction approach, Baseline Cancellation UMBIR (BACU), for enhanced ultrasonic imaging in SHM.
• To mitigate baseline-related artifacts and improve the fidelity of ultrasonic images for detecting rebar corrosion.

Main Methods:

• Developed BACU by integrating baseline subtraction into the ultrasonic model-based iterative reconstruction (UMBIR) framework.
• Suppressed dominant direct arrivals and low-rank background responses while preserving target signals.
• Validated the method using synthetic experiments on a concrete specimen with an embedded rebar.

Main Results:

• BACU demonstrated superior clutter suppression and sharper rebar localization compared to conventional UMBIR.
• The proposed method showed improved contrast preservation across different corrosion levels.
• Enhanced robustness to modeling errors and limited array coverage was observed.

Conclusions:

• BACU offers more reliable and interpretable ultrasonic reconstructions for SHM.
• The method advances non-destructive evaluation and long-term monitoring of critical infrastructure.
• Improved detection of rebar corrosion supports enhanced structural durability assessments.