Definition - What does Bug Hole mean?
This is a regular or irregular cavity that occurs on the surface of a concrete as a result of trapped air bubbles during the placement and consolidation of concrete—commonly on vertical surfaces where concrete is cast in place. Their effect on corrosion is determined by the size and depth of the cavity.
Corrosionpedia explains Bug Hole
In the matrix of the concrete, the air void and excess water tend to bleed out of the mixture due to a difference in density. The only way equilibrium is achieved is by taking the nearest route to the top.
It is caused by high-amplitude vibrators, the use of the machine effectively, the application thickness and the concrete mix workability property. The mix design is determined by the aggregate grading, size and type.
Apart from affecting the aesthetic value of the concrete, a bug hole creates room for failure and corrosion. To prevent this defect from happening, it is advisable to use permeable forms, workable and flowing mixtures, and maintaining a proper vibration for unification. These forms assist in removing the air and water easily onto the top of the surface, thus preventing corrosion within the matrix of the concrete.