Why concrete spalls
Common contributors include reinforcement corrosion, impact, fire, freeze–thaw in relevant climates, poor compaction, insufficient cover, chemical exposure and previous incompatible repairs.
The exact response should be defined from verified site conditions, relevant design information and the performance objective. Where evidence is incomplete, further investigation is safer than assuming the visible symptom tells the whole story.
Start beyond the visible edge
Delamination often extends beyond the fallen area. Sounding, mapping and investigation help define repair boundaries and reveal reinforcement condition.
The exact response should be defined from verified site conditions, relevant design information and the performance objective. Where evidence is incomplete, further investigation is safer than assuming the visible symptom tells the whole story.
Treat the cause
If corrosion is active, simply covering exposed steel may trap the problem. Moisture, chlorides, carbonation, leakage and electrical continuity can influence the broader strategy.
The exact response should be defined from verified site conditions, relevant design information and the performance objective. Where evidence is incomplete, further investigation is safer than assuming the visible symptom tells the whole story.
Repair sequence
Typical work includes safe breakout, clean edges, reinforcement cleaning and assessment, bar replacement or supplementation where designed, substrate preparation, repair placement, curing and protection.
The exact response should be defined from verified site conditions, relevant design information and the performance objective. Where evidence is incomplete, further investigation is safer than assuming the visible symptom tells the whole story.
Compatibility matters
Repair material strength alone is not enough. Shrinkage, stiffness, thermal behavior, thickness, orientation, application method and exposure affect long-term performance.
The exact response should be defined from verified site conditions, relevant design information and the performance objective. Where evidence is incomplete, further investigation is safer than assuming the visible symptom tells the whole story.
Frequently asked questions
Concrete spalling is the loss or detachment of surface concrete. A durable repair removes unsound material, addresses the deterioration mechanism and rebuilds the section with compatible materials.
Yes. General guidance cannot determine the cause, capacity, material compatibility or safe repair scope for a specific structure.