Fusion Bonded Epoxy Coating Study for Anchor Reinforcement-PPT Presentation

PPT Presentation

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The study compared green ASTM A775 and purple ASTM A934 fusion-bonded epoxy coatings used to protect reinforcing steel. Both are powder-applied dielectric barriers with similar surface-preparation and testing requirements. A775 permits field bending and has stricter impact requirements; A934 requires fabrication before coating.<br /><br />Initial independent laboratory tests produced mixed results. A934 passed elevated-temperature cathodic disbondment testing, while A775 did not, but all samples failed the ambient-temperature test. All samples passed abrasion testing. Impact results were poor for both coatings, with more A934 samples failing. Some chemical- and salt-spray results could not be interpreted because A775 samples had improper substrate preparation.<br /><br />A second testing program used carefully prepared plate samples and more demanding tests. A775 performed better in abrasion and impact resistance, while A934 performed better in salt-spray resistance and electrical impedance spectroscopy. Both coatings passed the flexibility test at a 3-degree bend, but A934 failed at 5.5 degrees. The researchers cautioned that these laboratory samples and preparation methods do not represent production material delivered to a job site.<br /><br />Overall, both coatings can provide durable, effective corrosion protection when the steel is properly prepared, the coating is correctly applied, and handling damage is repaired. The study found no evidence that either coating performs significantly better overall when applied properly. Applicator process was identified as the most important factor. Epoxy may not be suitable for ground anchors or soil nails in aggressive environments, where encapsulation is preferred.

Keywords

ASTM A775

ASTM A934

fusion-bonded epoxy

reinforcing steel

corrosion protection

cathodic disbondment

abrasion resistance

impact resistance

salt-spray testing

applicator process