Honeycombing
CSI Division 03, Concrete
Visible voids and gaps left inside cured concrete, resembling a honeycomb, when the mix isn't properly vibrated during placement and the aggregate doesn't fully consolidate around the rebar and into the corners of the formwork.
Why it matters
Honeycombing isn't just a cosmetic flaw. The voids it leaves weaken the concrete structurally and can expose rebar directly to moisture and air, leading to corrosion that weakens the reinforcement from the inside over time.
On a real project
After stripping the formwork from a column, a crew finds visible honeycombing along one face where the concrete wasn't vibrated thoroughly enough during placement, and the area has to be evaluated and repaired before the column is considered acceptable.
Who this matters most to
A Concrete Worker vibrates concrete thoroughly during placement specifically to prevent honeycombing, working the vibrator methodically rather than rushing through the pour.
Where this goes wrong
A crew under schedule pressure rushes through vibrating a heavily reinforced column, leaving sections where the concrete never fully consolidated around the rebar. The resulting honeycombing isn't caught until formwork is stripped, and the column has to be repaired or, in a severe case, removed and repoured.