Reinforcement Corrosion

Inspection Requirements

• Map rust staining, cracking and delamination across all affected elements.
• Hammer tap test to identify drummy or delaminated concrete cover.
• Measure concrete cover depth with a cover meter across the element.
• Break out locally to expose reinforcement and assess corrosion extent and section loss.
• Test carbonation depth using phenolphthalein indicator on freshly broken surfaces.
• Test chloride content at reinforcement depth where marine or salt exposure is suspected.
• Assess concrete permeability, quality and likelihood of further ingress.

Typical Repair Methodology

The final repair scope must be confirmed by the project engineer and selected repair system. The sequence below outlines a typical methodology for reinforcement corrosion repairs.

1. 01.Confirm repair scope with the project engineer prior to commencing breakout.
2. 02.Break out concrete around corroded reinforcement until clean steel and sound concrete are exposed on all sides.
3. 03.Continue breakout to a minimum of 25mm behind the reinforcement bar.
4. 04.Assess reinforcement section loss and confirm acceptability with the engineer before proceeding.
5. 05.Replace or supplement reinforcement only where directed by the engineer.
6. 06.Clean reinforcement to remove all corrosion, scale and loose material to an approved cleanliness standard.
7. 07.Remove all dust, laitance and deleterious material from repair surfaces.
8. 08.Prime exposed reinforcement with an approved corrosion-inhibiting primer and allow to cure.
9. 09.Pre-wet the prepared concrete substrate and remove standing water before repair.
10. 10.Apply an approved bonding slurry or primer compatible with the selected repair mortar.
11. 11.Apply repair mortar in layers within approved thickness limits and compact firmly around reinforcement.
12. 12.Finish the repair flush with surrounding concrete to the required profile and tolerance.
13. 13.Cure repaired areas immediately using approved curing methods and protect from early drying.
14. 14.Apply anti-carbonation or protective coating to the repaired and surrounding surfaces where required.
15. 15.Record QA photos, repair locations, products used, batch numbers and completed hold points.