Freshly placed concrete holds entrapped air and leaves voids against forms and rebar until it is vibrated or rodded. Internal vibrators run at roughly 8,000 to 12,000 vibrations per minute, inserted vertically at regular spacing and held a few seconds until the surface turns glossy and large bubbles stop rising. Under-consolidation leaves honeycomb and bugholes; overdoing it in a wet mix drives the stone down and the paste up.
Inspector wants proper consolidation in those corners, so stinger every 18 inches and down into the last lift.
Also heard as
- vibration
- vibrating
- rodding
Related terms
Stinger
An internal concrete vibrator, or specifically the vibrating head on the end of its flexible shaft.
Honeycomb
Patches of bare, loosely bound stone with open gaps, left where paste never worked in around the coarse rock.
Bugholes
Small surface pits on vertical formed concrete left by air bubbles trapped against the form face.
Lift
One layer of concrete placed in a wall, column or mass pour, or the height cast between horizontal joints.
Segregation
Separation of coarse aggregate from the mortar in fresh concrete, leaving rock-heavy and paste-heavy zones.