Well-performing bridge coating systems are founded upon proper preparation prior to coating. Most coating systems require a near white metal blast-cleaned finish prior to the primer coat. However, there is a possibility for surface contamination from either not being removed during the blast cleaning operation or contaminated blast media, causing contamination. This project aims to understand what an acceptable level of contamination is prior to coating, identify what cleaning methods are required to achieve the acceptable level, and identify what means are necessary to measure the surface contaminant concentrations.
The key project objectives are to:
(1) Identify effective means of measuring chloride, nitrate, and sulfate contamination on the surface of uncoated steel.
(2) Identify proper techniques for cleaning uncoated steel to a target level of contamination.
(3) Determine what levels of contamination are detrimental to bridge coating performance.