The National Academies

NCHRP IDEA 20-30/IDEA 164 [Completed (IDEA)]

Laser Spectroscopy for Rapid Profiling of Steel Bridge Coatings, Corrosion, and Heavy Metals
[ NCHRP 20-30 (NCHRP-IDEA) ]

  Project Data
Funds: $137,238
Staff Responsibility: Inam Jawed
Research Agency: Chesner Engineering, PC
Principal Investigator: Warren Chesner
Fiscal Year: 2012

The project was designed to develop and demonstrate the application of a laser scanning technology to rapidly identify and profile the presence of heavy metals (Pb, Cd, and Cr) and titanium (Ti) in paint coatings. In addition, the potential for using laser scanning to identify the type of coating used and the presence and the severity of corrosion under layers of coatings on steel structures was investigated. Finally, special testing was undertaken to evaluate the use of laser equipment to drill through and depth-profile coating layers.   Findings have shown that laser spectroscopy readily distinguishes coatings with high levels of Pb, Cd, and Cr from coatings with minimal levels. The presence and concentration of titanium in coatings is readily identifiable. Zinc-rich coatings are easily distinguishable from other coatings and epoxies. Study findings also showed that it is possible to distinguish between degrees of corrosion. The research team developed and successfully tested a combined drilling and laser ablation tool to achieve a high resolution depth profile of coating layers.  Such a tool has applicability as a research tool as well as a field inspection tool to assess the presence of coatings containing high levels of heavy metals, the thickness of the coatings, the type of coating, and level of corrosion at the surface and under the coating layers, The depth profiling technology featured in this research has the potential for use as a diagnostic tool in a variety of structures including concrete, asphalt, and steel surfaces.
The final report is available.

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