Quality with FransWhat it looks like
When the forms are stripped you see rough, stony patches where the coarse aggregate is visible with little or no cement paste between the stones. It often shows at the bottom of walls and columns, along form joints, around openings and boxouts and where reinforcement is congested. It is different from blowholes (small, smooth air voids in the surface skin), which are mainly a finish issue.
Minor or serious?
| Type | What you see | Typical action |
|---|---|---|
| Surface / minor | Shallow, small area, stones visible but tightly packed, no steel showing | Remove loose material, clean, wet, fill with an approved repair mortar to the method statement |
| Moderate | Deeper voids, larger area, loose stones come out when tapped | Break out to sound concrete, record size and depth, repair with approved structural repair mortar |
| Severe | Deep voids, large areas, reinforcement exposed, or in a critical zone (column base, beam-column joint, under a bearing) | Stop and report. Structural engineer to assess before any repair; may need non-destructive testing, cores, grouting or even removal |
Sources agree on the principle (size, depth and exposed steel decide the severity) but do not give one universal depth limit. The acceptance level should come from your project specification and the engineer, so do not use a "rule of thumb" number as a pass/fail.
Why this matters for QA/QC
Honeycombing is not just ugly. Open voids mean less cover and an easy path for water, chlorides and carbon dioxide to reach the steel, and in a column base it can mean less concrete carrying the load. The worst thing I see on site is a quick plaster job the morning after stripping, before QA/QC has seen it. Once it is covered, nobody knows how deep it went.
Treat it like any non-conformance: photograph it, measure it, raise an NCR if your system needs one, and get the repair method approved. Then fix the cause for the next pour: tighter form joints, the right slump or a flowable mix in congested areas, proper vibration and enough access for the poker.
Check on your site tomorrow
- Make a rule: no repair or plastering of stripped concrete until QA/QC has inspected and recorded it.
- Check that an approved concrete repair method statement and repair materials are in place before the next pour.
- Before the next wall or column pour, check form joints and kickers are sealed and the formwork is tight.
- In congested areas, check there is room for the poker and that the mix (slump, aggregate size) suits the job.
- Watch one pour: correct vibration spacing and time, concrete placed in layers, no dropping from height into narrow forms.
The 31-point checklist I use before every pour: bar sizes, spacing, cover and laps against the approved drawing.
Download the checklist
Sources: TxDOT Concrete Repair Manual: Voids due to honeycombing · CCAA Guide to Concrete Construction: Control of surface finishes · ACI University: As-cast concrete finishes, specifications, defects and repairs · Construction World: types of minor concrete defects and remedies · For Construction Pros: tips to minimise consolidation issues. Summary in my own words; your project specification and the structural engineer decide acceptance and repair.