| Abstract: | Protecting concrete bridge substructures against deterioration over time is an important aspect of bridge preservation, and it is routinely conducted by state departments of transportation. The application of coatings and sealers to protect bridge substructure concrete from corrosion is a common practice. However, a laboratory-based performance evaluation of potential sealers and coatings on a representative concrete substrate is crucial for selecting suitable coating/sealer products that meet project requirements. In the present research project, a systematic laboratory-based performance evaluation test protocol was developed to evaluate the effectiveness of representative coating/sealer products (three water-based coatings, three solvent-based coatings, and two sealers) on resisting moisture and chloride ingress through substructure concrete and achieving adequate adhesion performance (for coatings) under both normal and accelerated weathering conditions. Water absorption (ASTM D6489) and sorptivity (ASTM C1585) tests were conducted to evaluate moisture resistance, and rapid chloride permeability (ASTM C1202), chloride ponding (ASTM C1556), and innovative direct corrosion measuring tests (steady-state and accelerated methods) were conducted to evaluate chloride-induced corrosion resistance of the tested sealers and coatings. Monitoring through the measurement of dry film thickness for coating and depth of penetration for sealers was found to be effective in confirming a proper application. The solvent-based coating and sealers better resisted moisture and chloride ingress into the concrete substrate than the water-based coatings. Similarly, the solvent-based coatings showed higher pull-off adhesion strength than the water-based coatings. Ranking through comparative assessment of the tested products based on their performance in the selected tests under both normal and weathered conditions was considered a measure of corrosion protection effectiveness and useful to select suitable products for field applications. |
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