Who should run this inspection?

The GC's superintendent or earthwork QC tech walking the section with the stabilization crew before compaction begins.

When in the schedule should this walk happen?

After the subgrade is shaped and proof-rolled, once additive is spread and mixed but before the first compaction pass locks it in.

Why do these items ask for a photo?

11 of the 15 items call for photo evidence, 15 photos in all. A checklist answer without the photo is a claim; the photo is what makes the record worth something in a dispute and lets a reviewer approve work without re-walking the job.

What most often fails a soil stabilization rough-in inspection?

Additive spread by the truckload with no bag or ticket count against the design rate, so a light section goes in undetected. Mixer set for a shallow pass that leaves an unstabilized layer under the design depth, only found when the section pumps later. Soil mixed dry of the moisture window because the crew was chasing daylight, so it never reaches density.

Can I use this checklist in RTI?

Yes. Start a free RTI workspace, build this list as a checklist, and the Photo Gate holds the submit button until every mandatory item is answered and its photos are attached. Approved inspections roll into a branded turnover package with a tamper evident audit trail.

Free checklist

Soil stabilization

Soil stabilization rough-in inspection checklist

Soil stabilization rough-in is the last time the work is fully visible. Once the cover inspection passes and the walls, ceilings and slabs close, every defect left behind becomes a demolition bill. This checklist walks the rough-in in the order the work goes in, with the photo each item needs before it gets buried. Work is commonly verified against the project geotechnical report and specifications. Confirm the edition your authority having jurisdiction has adopted.

Start free with this checklist Download as PDF

The checklist

Every item, and the photo evidence it needs

The photo count on each row is what RTI would require before the item can be submitted. Work the list here and watch the gate hold, or load it into RTI and let it enforce the real thing.

Design values and testing setup

Stabilization design values on hand for this section
Current geotechnical report and stabilization design at the field office, with additive percentage, mixing depth, moisture range and density target noted for the day's stations.
No photo
Moisture-density curve for the treated soil on file
Testing lab's curve run on the soil with the design additive in it, not the raw soil, so field density and moisture are compared to the right target.
No photo

Subgrade and proof-roll

Subgrade shaped and proof-rolled before additive
Section proof-rolled and any soft or pumping spots dug out and replaced, grade and cross-slope close to design before spreading starts.
Section limited to what can be mixed and compacted in the window
Spread area sized to the crew's compaction capacity so no mixed soil sits and dries before it's rolled.
Mixer path walked for utilities and structures before cutting
Valve boxes, manholes, shallow lines and irrigation marked and flagged out of the mixer's cut depth, with the super confirming locates are current.
No photo
Geotextile or geogrid, where the design uses one, laid to the plan
Product matches the approved submittal, rolls oriented and overlapped as the stabilization design shows, no wrinkles or tears before fill goes over it.
No photo

Additive and application rate

Additive type matches the mix design
Lime, cement or fly-ash matches what the geotechnical mix design calls for, delivery tickets photographed against the spec.
Spread rate verified against the design
Application rate confirmed by bag count or spreader ticket over the measured area, compared to the pounds per square yard the design requires.
Spread uniformity checked across the spreader width
Pans or tarps of known area laid in the spreader's path and the catch weighed by the testing lab or QC tech, or the distributor's rate check on slurry; streaks or bare lanes re-spread.
Spread additive mixed the same day, not left exposed
Additive on the ground blended in before wind or rain can carry it off; no spread strips left overnight or washed into low spots.
Dust from spreading and mixing held on the section
Observed from upwind and outside the spreading and mixing lanes: no additive drifting onto roads or adjacent work, spreading paused in gusty wind.

Mixing and moisture

Mixing depth checked in the section
Mixer cut probed or dug to confirm the additive is blended to the full design depth, not just the top few inches.
Moisture conditioned into the compaction window
Soil watered or aerated to the moisture range the design calls for before compaction, uniform color with no dry pockets or ponded water.
Pulverization checked after the mixing pass
Mixed soil sampled by the testing lab and screened for clods larger than the specifications allow; extra mixer passes run until it meets the gradation.
Lab moisture reading taken before the first roller pass
Testing lab's field moisture on the mixed soil compared to the range from the treated-soil curve, logged with the station and time.

What usually sends this back

The failures are almost always the evidence, not the work

Additive spread by the truckload with no bag or ticket count against the design rate, so a light section goes in undetected.
Mixer set for a shallow pass that leaves an unstabilized layer under the design depth, only found when the section pumps later.
Soil mixed dry of the moisture window because the crew was chasing daylight, so it never reaches density.

Common questions

6 answers

What does this soil stabilization rough-in checklist cover?: 15 items across 4 sections, covering design values and testing setup, subgrade and proof-roll, additive and application rate, mixing and moisture. Each item spells out what the person walking the job is actually looking for, not just a box to tick.
Who should run this inspection?: The GC's superintendent or earthwork QC tech walking the section with the stabilization crew before compaction begins.
When in the schedule should this walk happen?: After the subgrade is shaped and proof-rolled, once additive is spread and mixed but before the first compaction pass locks it in.
Why do these items ask for a photo?: 11 of the 15 items call for photo evidence, 15 photos in all. A checklist answer without the photo is a claim; the photo is what makes the record worth something in a dispute and lets a reviewer approve work without re-walking the job.
What most often fails a soil stabilization rough-in inspection?: Additive spread by the truckload with no bag or ticket count against the design rate, so a light section goes in undetected. Mixer set for a shallow pass that leaves an unstabilized layer under the design depth, only found when the section pumps later. Soil mixed dry of the moisture window because the crew was chasing daylight, so it never reaches density.
Can I use this checklist in RTI?: Yes. Start a free RTI workspace, build this list as a checklist, and the Photo Gate holds the submit button until every mandatory item is answered and its photos are attached. Approved inspections roll into a branded turnover package with a tamper evident audit trail.

Related checklists

Soil stabilization FinalSoil stabilization final inspection checklistCompaction and density, cure or mellowing period, finished grade and surface tightness confirmed before the next course14 items12 photos Soil stabilization PunchSoil stabilization punch checklistSoft or pumping areas re-worked, curing membrane and dust addressed, grade corrections closed9 items4 photos

Run it with the Photo Gate

A checklist nobody can submit half-finished

Load this list into RTI, stick a QR tag on the area it covers, and the submit button stays locked until every mandatory item is answered and the 15 required photos exist. Approved walks roll into a branded turnover package with a tamper evident record behind every line.