Concrete & Structural Defects
Concrete Spalling
Concrete spalling is the breaking away, delamination or loss of concrete cover, commonly caused by corrosion of embedded steel reinforcement, moisture ingress, carbonation, chloride exposure, inadequate concrete cover or poor concrete quality.
Common Signs
- Rust staining
- Cracked or drummy concrete
- Delaminated concrete cover
- Exposed reinforcement
- Loose concrete fragments
Common Causes
- Reinforcement corrosion
- Carbonation
- Chloride contamination
- Low concrete cover
- Water ingress
- Poor compaction or honeycombing
Risk of Neglect
- Falling concrete hazard.
- Progressive reinforcement corrosion.
- Loss of reinforcement section.
- Larger breakout areas over time.
- Water ingress into adjacent elements.
- Higher future repair cost.
- Potential structural capacity concerns.
Inspection Requirements
- Map visible cracking, rust staining, delamination and spalled areas.
- Hammer tap or chain drag test to identify drummy or delaminated concrete.
- Expose reinforcement locally where required to confirm corrosion extent.
- Check concrete cover depth and reinforcement condition.
- Assess likely water source, waterproofing failure or façade ingress path.
- Consider carbonation, chloride and concrete condition testing where required.
Start Inspection Checklist
Create a project inspection record, add defect locations, upload photos, and save notes for scope writing.
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 concrete spalling repairs.
- 01.Allow for concrete spalling repairs to be measured on a litreage or volume-based rate where required.
- 02.Remove concrete around exposed or corroded reinforcement until clean steel and sound concrete are exposed.
- 03.Remove or replace reinforcement only where directed by the engineer or superintendent.
- 04.Prepare all concrete surfaces to a roughened profile suitable for repair mortar bonding.
- 05.Clean exposed reinforcement to remove corrosion, scale and loose material to an approved steel cleanliness standard.
- 06.Remove dust, loose particles, laitance and deleterious material from all repair interfaces.
- 07.Prime exposed reinforcement with an approved corrosion protection primer.
- 08.Pre-wet the prepared concrete substrate where required and remove standing water before repair.
- 09.Apply an approved bonding slurry or substrate primer compatible with the repair mortar system.
- 10.Apply repair mortar while the bonding coat remains active and within manufacturer requirements.
- 11.Apply repair mortar in layers within approved thickness limits and compact around reinforcement.
- 12.Finish the repair to match the surrounding profile and required surface tolerance.
- 13.Cure repaired concrete using approved curing methods immediately after application.
- 14.Apply protective coating, membrane or anti-carbonation coating where required.
- 15.Record QA photos, repair locations, products used, batch details and completed hold points.
Related Repair Systems
- Polymer-modified repair mortars
- Cementitious repair mortars
- Epoxy repair mortars
- Bonding agents
- Rebar primers and inhibitors
- Curing compounds
- Formwork materials
- Tie wire and fixings
- Cement and aggregates
- Abrasives, blades and tools
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