What are bug holes?
Bug holes are surface voids caused by entrapped air migrating from fresh concrete to the formwork surface.
These are most common in vertically poured concrete where it is difficult for the entrapped air to reach the top surface and escape.
How do bug holes damage concrete structures?
In most cases, bug holes do not cause structural problems but may impair the visual appearance of the concrete.
Where the concrete cover provided to the reinforcement is low, however, this defect may significantly accelerate the initiation of reinforcement corrosion.
What causes bug holes in concrete?
Entrapped air in fresh concrete.
Inadequate compaction equipment or procedures.
Improper formwork.