Spalling
Concrete breaking away from a surface in flakes or chunks, exposing the aggregate or reinforcement beneath. Common at edges, joints, and over corroding steel.
What does spalling mean?
Spalling has several distinct causes that require different repairs: corroding reinforcement expanding and pushing off the cover, freeze-thaw damage, impact, or fire. Corrosion-driven spalling is progressive and worsens once steel is exposed, because the protection is gone. On flatwork, spalling at joints and edges often reflects saw timing, poor consolidation, or deicing salt exposure.
In practice
Chunks breaking off a parking garage ceiling with rusted bar visible is corrosion spalling, and it is a structural maintenance issue rather than cosmetic.