4.2 Coated Reinforcement: Epoxy-Coated & Galvanized Handling, Inspection & Repair

4.2 Coated Reinforcement: Handling, Inspection & Repair

Inspect coated bars at receipt, after handling and before they are concealed. The steel grade, bar size and coating are separate requirements. Keep bundle identification and check the coating specification in the approved submittal. Coating damage can expose steel to the surrounding concrete and compromise the specified protection.

Identify the coating system

A factory coating test and a field repair measurement answer different questions. Do not compare a scrape with the factory holiday average. Check bends, cuts, bar contacts and lifting points for visible damage, and identify the part of the bar represented by each measured area.

Protect the coating during handling

ACI 301-20 Section 3.1.3.2 calls for handling and storage equipment and methods that protect the coating. A775-17 Appendix X1 recommends protected contact areas on equipment, lifting arrangements that avoid bundle abrasion and padded or suitable supports above the ground. Keep coated and uncoated bars separated in storage. Under ACI 301-20, use opaque protective material when outdoor storage exceeds two months. A775 Appendix X1 recommends circulation around protected stacks to limit condensation and notes that corrosive environments may require earlier protection.

Inspect coating at support and tie locations. ACI 301-20 Section 3.3.2.4 calls for epoxy- or polymer-coated tie wires on epoxy- or dual-coated reinforcement and compatible coated or composite wall spacers. Check other supports against the project and referenced support specification. ASTM A775 Appendix X1 recommends rubber or nonmetallic vibrator heads where immersion vibrators are used around epoxy-coated bars.

Separate the pre-shipment and field criteria

ASTM A775/A775M-17 Section 11 limits repaired damaged coating before shipment to 1% of the surface area in each one-foot length, excluding patched sheared or cut ends from that limit. It requires repair of fabrication and handling damage to the point of shipment using Annex A2 patching material. Its repaired areas have a minimum coating thickness of 7 mils. Section 11 requires coating cut ends and prohibits flame cutting. Appendix X1 gives separate jobsite guidance of 2% per foot.

When ACI 301-20 Section 3.2.1.2(b) applies, damaged epoxy coating incurred in shipment, storage, handling and placing must be repaired with the applicable material per its manufacturer's instructions. Do not use a bar if damaged coating exceeds 2% of surface area in any linear foot. Include prior repaired damage from before shipment as required by the applicable coating standard. The percentage is local to each one-foot length. A low average over the bar's full length cannot excuse an excessive local area.

Field example. A one-foot segment has a documented surface area of 24.0 in². In that segment, 0.15 in² was repaired before shipment and 0.40 in² of additional damage occurred during placing. Total affected area is 0.55 in². The field limit under the specified ACI 301-20 criterion is $0.02(24.0)=0.48$ in². The segment exceeds the limit, even though the new damage alone is below it. Report the location, product, measured areas and applicable criterion.

Verify repair and disposition

Use the patching material identified by the applicable standard and approved documents. Check preparation, coverage and cure against the manufacturer's written instructions. A775 Appendix X1 calls for removing rust and allowing the material to cure before concrete is placed. Under ACI 301-20 Section 3.3.2.9, field cutting requires acceptance by the Architect/Engineer. Coat cut epoxy bar ends with the applicable repair material and follow the separate requirements for zinc-coated ends.

Record measured areas, prior repaired areas, coating identification, notifications and the reinspection result. Coordinate the approved corrective work before concealment. Use the field limit from the applicable contract and the applicable pre-shipment requirements for supplier certification.