The National Academies

NCHRP IDEA 20-30/IDEA 176 [Completed (IDEA)]

Contactless Electrode for Fast Survey of Concrete Reinforcement Corrosion
[ NCHRP 20-30 (NCHRP-IDEA) ]

  Project Data
Funds: $100,000
Staff Responsibility: Inam Jawed
Research Agency: University of South Florida
Principal Investigator: Alberto A. Sagues
Fiscal Year: 2013

This project developed and demonstrated a Kelvin Probe (KP) electrode device for rapid and stable electrode potential mapping for early corrosion detection in concrete steel reinforcement in highway structures. An existing stationary miniature proof-of-concept version of a KP electrode device was scaled up to a mobile and practical large size unit suitable for realistic field conditions. Operation of the scaled-up contactless vibrating probe on a mobile platform was demonstrated on an outdoor reinforced concrete slab. The acquired probe data created a potential map of the slab surface that successfully identified the position of the anodic spot.  The rapid probe operation was validated against data obtained on the same surface using the traditional and slower contact electrode method.  Performance parameters needed to acquire useful data under various vehicle speeds were analyzed, and a conceptual approach using an alternative non-vibrating translating disk to operate at even greater scan speeds was analyzed. A duplicate vibrating unit for testing the coordinated operation was constructed, incorporating an advanced distance transducer and consolidation of the digital processing units into a powerful signal acquisition unit. A post-scanning deconvolution of the KP output was implemented to sharpen the resulting surface potential map to allow for faster travel speeds. Evaluation of the mobile units was conducted in two field tests in cooperation with the Florida Department of Transportation on a pier deck that had previously served as the Sunshine Skyway Bridge access. The field tests demonstrated the practical feasibility of the concept of using a rapidly scanning contactless surface probe to conduct potential mapping of a highway bridge surface for corrosion detection. Additional work needed for further improvement of the KP device and its implementation and commercialization is suggested.
The final report is available.

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