Optically active pigments (OAPs) fluoresce under light exposures with wavelengths (nm) producing emissions in the visible spectra (380 to 740 nm). They are used as paint pigments to aid visual inspection of applied coatings for defects such as pin-holing and incomplete coverage. OAP coatings are widely used in various industries outside of bridge maintenance painting.

This study addressed the laboratory evaluation and field trial of an OAP coating for KYTC bridges. OAP coatings were evaluated for inspectability and accelerated weathering performance in a laboratory test program. After successful laboratory performance, OAP coatings were specified for a KYTC bridge painting project incorporating two deck-girder bridges. One bridge was coated with an OAP zinc urethane primer/non-OAP epoxy mid-coat/OAP urethane top-coat system. The second bridge was coated with a non-OAP zinc urethane primer/OPA epoxy mid-coat/non-OAP urethane top-coat. Field observations revealed that OAP coatings improved inspectability by making uncoated and thinly coated areas more readily identifiable.

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Prepared in cooperation with the Kentucky Transportation Cabinet, Federal Highway Administration, and U.S. Department of Transportation.

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© 2013 University of Kentucky, Kentucky Transportation Center

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