Shows up when forms are stripped as patches of bare stone with open gaps between, usually at the bottom of walls and columns, around congested rebar and at form joints that leaked paste. Causes include poor consolidation, segregation, harsh mixes and placing too fast. Shallow honeycomb is chipped out and patched; deep honeycomb near reinforcement goes to the engineer for a structural repair.
Stripped the column and it's honeycomb at the base where the stinger never got down past the ties.
Also heard as
- honeycombing
- rock pocket
- voids
Do not mix it up with
- Bugholes: Bugholes are small isolated air voids in the surface; honeycomb is a larger zone with mortar missing between stones.
Related terms
Consolidation
Working fresh concrete, usually by vibration, so it fills the form completely and releases trapped air.
Segregation
Separation of coarse aggregate from the mortar in fresh concrete, leaving rock-heavy and paste-heavy zones.
Stinger
An internal concrete vibrator, or specifically the vibrating head on the end of its flexible shaft.
Bugholes
Small surface pits on vertical formed concrete left by air bubbles trapped against the form face.