Non-invasive Detection of Extent of Corrosion in Steel Reinforcing Bars by Magnetic Force Measurement
Published in Advances in Non-destructive Evaluation, Lecture Notes in Mechanical Engineering (Springer), 2019
This work proposes a simple non-destructive technique to detect corrosion of steel reinforcing bars in reinforced cement concrete (RCC) by measuring magnetic force changes with a strain-gauge–based cantilever setup. A neodymium magnet exerts force on rebars, and the resulting deflection of a strain-gauge cantilever is measured using a Wheatstone bridge circuit. The voltage output correlates directly with the degree of corrosion.
PVC-coated samples were also tested, and results confirm that insulation does not significantly affect detection accuracy — demonstrating applicability to in-situ corrosion monitoring of insulated pipelines.
Key Findings
- Magnetic-force–based measurement shows clear sensitivity to the degree of corrosion in steel rebars.
- Bridge voltage decreases systematically with increased corrosion due to loss of ferromagnetic material.
- Results are consistent for both bare and PVC-insulated rebars, confirming insulation does not hinder detection.
- The approach provides a simple, low-cost, and calibration-free method suitable for in-situ monitoring of reinforced concrete structures.
Recommended citation: Tamhane D., Banerjee S., Tallur S. Non-invasive Detection of Extent of Corrosion in Steel Reinforcing Bars by Magnetic Force Measurement. In: Mukhopadhyay C.K., Mulaveesala R. (eds) Advances in Non-destructive Evaluation. Lecture Notes in Mechanical Engineering. Springer, 2021.
Download Paper