Rebar Inspection Procedures for Epoxy-Coated Reinforcing Steel: A Field Guide
By David McDonald, Epoxy Interest Group | Adapted from ASPIRE, Fall 2011
Epoxy-coated reinforcing bars have been protecting bridges, parking structures, and marine concrete from chloride-induced corrosion since 1973. But that protection only works if the coating arrives at the pour intact. That is why rebar inspection—specifically, careful inspection of epoxy-coated reinforcing steel before and during concrete placement—is one of the most important quality-control steps on any corrosion-sensitive project.
This guide walks through the rebar inspection procedures every contractor, inspector, and resident engineer should follow to keep coated bars in service for the full design life of the structure.
Key Takeaways
- Rebar inspection of epoxy-coated reinforcing steel before concrete placement is the single most important step for ensuring long-term corrosion protection.
- Coated bars require careful handling—use spreader bars, padded slings, timber cribbing, and coated tie wire to avoid damaging the epoxy.
- Inspectors should verify bar size, spacing, clear cover, lap lengths, and bend integrity, and reject any bar with more than 2% damage in a 1-foot section.
- Concrete placement practices—S-bend pump lines, plastic-headed vibrators, and protected runways—prevent coating damage during the pour.
- Bars exposed for more than 30 days must be covered with opaque material to protect against UV, salts, and condensation.
Why Rebar Inspection Matters for Epoxy-Coated Steel
The most common epoxy-coated bars are green and meet AASHTO M 284 (ASTM A775). Some agencies specify purple or gray bars meeting ASTM A934 for prefabricated assemblies. Both products remain the most widely specified and researched corrosion-resistant reinforcement in North America.
A thorough rebar inspection before the concrete truck arrives is the last opportunity to catch and repair coating defects after the pour; the cost of correction is orders of magnitude higher.
Rebar Inspection Procedures for Epoxy-Coated Reinforcing Steel
Use the following procedures to minimize damage and verify acceptance before concrete placement.
1. Lifting and Handling
- Lift coated bars with a spreader bar or at multiple pickup points to minimize sag.
- Never drag bars across the ground or other bundles.
- Do not lift with bare chains or cables—use padded or nylon slings.
- Store bars on timber cribbing, off the ground, and out of standing water.
2. Forms, Supports, and Tie Wire
- Oil the forms before placing reinforcement so coated bars never sit directly on oiled surfaces.
- Support coated bars on epoxy-coated or nylon chairs—never on bare steel supports.
- Tie bars only with coated tie wire to prevent abrasion at every intersection.
3. Cutting, Bending, and Splicing
- Flame cutting is prohibited.
- Field bending is allowed only with the engineer’s permission, and only on bars that meet AASHTO M 284 (ASTM A775). Prefabricated bars under ASTM A934 must not be bent after coating.
- Mechanical splices must be epoxy-coated. Welding requires the engineer’s explicit approval, and any heat-affected zone must be cleaned and patched with approved repair material.
4. Pre-Pour Rebar Inspection Checklist
Immediately before concrete placement, the inspector should verify:
- Bar size, type, and spacing match the drawings.
- Clear cover meets the specified minimum at every face.
- Lap lengths are correct and bars are tied tightly at laps.
- Bends are inspected for cracking or fractures—any unrepaired damage is rejected.
- Total coating damage does not exceed 2% in any 1-foot section (sheared or cut ends are excluded from the calculation).
- All visible damage, including welds and abraded areas, is cleaned and patched with the manufacturer’s approved repair material.
5. Protecting the Coating During Concrete Placement
- Avoid resting concrete hoses directly on the mat. Couplers can gouge the coating as the line is repositioned. A protected runway is recommended.
- Fit pump lines with an “S” bend so concrete does not free-fall directly onto coated bars.
- Use plastic-headed vibrators for consolidation—steel vibrator heads will scar the coating.
6. Long-Exposure and Storage Requirements
Bars that are partially cast and then left exposed for extended periods need additional protection from UV, salts, and condensation. If exposure exceeds 30 days, cover the bars with an opaque material that minimizes condensation. This single step prevents the most common cause of premature coating degradation on long-duration projects.
Frequently Asked Questions: Rebar Inspection for Epoxy-Coated Steel
How much coating damage is acceptable on epoxy-coated rebar?
Bars exhibiting more than 1% coating damage in any 1-foot section may be rejected. Sheared or cut ends are excluded from this limit, but all other visible damage must be repaired with the manufacturer’s approved patch material before concrete placement.
Can epoxy-coated rebar be bent in the field?
Field bending is permitted only with the engineer’s permission, and only on bars meeting AASHTO M 284 (ASTM A775). Prefabricated bars meeting ASTM A934 are bent before coating and cannot be re-bent on site.
Is flame cutting allowed on epoxy-coated reinforcing steel?
No. Flame cutting is prohibited because the heat destroys the surrounding coating and undermines corrosion protection. Use mechanical cutting, and patch any exposed steel before placement.
What tie wire should be used with epoxy-coated rebar?
Always use coated (typically epoxy- or nylon-coated) tie wire. Bare wire abrades the coating at every tie point, creating thousands of small corrosion initiation sites.
How long can epoxy-coated rebar be stored outside before placement?
There is no fixed shelf life, but bars exposed to sunlight, salts, or moisture for more than 30 days should be covered with an opaque tarp or sheeting that minimizes condensation. Storage on timber cribbing, off the ground, is also required.
What standards govern epoxy-coated reinforcing steel?
Two standards cover the most common products: AASHTO M 284 / ASTM A775 for bars coated after fabrication, and ASTM A934 for prefabricated bars coated after bending. Both are referenced throughout federal, state, and DOT specifications.
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Standards Referenced
- AASHTO M 284 — Standard Specification for Epoxy-Coated Reinforcing Bars: Materials and Coating Requirements
- ASTM A934 — Standard Specification for Epoxy-Coated Prefabricated Steel Reinforcing Bars