Subgrade Stabilization with Lime/Cement Checklist

Definition: Subgrade Stabilization with Lime/Cement is a field-ready checklist for inspectors and foremen verifying mix design, spread rate, moisture, mixing, compaction, and curing to achieve specified strength outcomes.

Confirms binder type, spread rate, and uniform mixing depth.
Controls moisture to OMC range and documents density achievement.
Validates curing and laboratory strength against approved targets.
Interactive, commentable, export-ready checklist with QR code authentication.

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Checklist

Subgrade Stabilization with Lime/Cement sets a clear, auditable process for verifying lime-treated and cement-stabilized subgrades from batching through compaction and curing. This checklist focuses on binder verification, spread rate control, moisture conditioning, thorough mixing, compaction to density, and confirmation of target unconfined compressive strength—without addressing pavement design. By aligning field activity with the approved mix design and practical acceptance tolerances, you reduce variability, avoid soft spots, mitigate shrink-swell soils, and achieve durable support for overlying layers. It covers pozzolanic reactions in lime treatment, cement stabilization behavior, optimum moisture content management, pulverization criteria, density testing, and curing protection. Use it to capture photos, readings, COAs, nuclear gauge outputs, and lab results while maintaining traceable approvals per approved project specifications and authority requirements. Start in interactive mode to tick items, add comments for non-conformances, and export records to PDF/Excel with a QR code for authentication.

Control binder selection, spread calibration, and mixing depth to ensure uniform treatment. Moisture is conditioned to the optimum range, pulverization is verified, and compaction achieves the required density, delivering consistent bearing support and reduced post-construction movement.
Quality assurance emphasizes measurable checks: calibrated application trials, moisture tests, pH confirmation for lime, density verification, and lab strength testing. Evidence includes photos, signatures, lot numbers, gauge readings, and survey shots attached directly to each task.
Interactive online checklist with tick, comment, and export features secured by QR code.
The workflow minimizes rework and delays by sequencing documentation, placement, testing, and curing protection. Clear tolerances guide acceptance on spread uniformity, moisture ranges, pulverization, straightedge, and density, keeping crews aligned with approved project specifications.

Pre-Work Documentation

1. Confirm approved stabilization mix design; record binder (quicklime/hydrated lime/cement), target binder percentage by dry soil mass, treatment depth, and target UCS age; attach signed approval.
2. Verify latest modified Proctor (MDD and OMC) for the treated soil; record lab ID, MDD (kg/m³), OMC (%), and test date; attach report.
3. Set out treatment limits and depth controls; stake edges, paint offsets, and mark depth on reclaimer; capture layout photos and foreman sign-off.
4. Check weather window: air temperature 5–38 °C, no heavy rain forecast within 24 h; upload forecast screenshot and site wind observations.

Materials Verification

5. Inspect delivered binder; confirm type matches submittal; record supplier, delivery ticket, lot numbers, and Certificate of Analysis; attach COA and delivery photos.
6. Verify dry, protected storage: pallets off ground, covers secured, no caking or moisture intrusion; photograph storage and note corrective actions if needed.
7. Calibrate spreader using a test strip and weighbridge (before/after); compute application rate (kg/m²) or % by dry soil mass; acceptance: within ±5% of target.
8. Confirm water source suitability and flow measurement; record meter serial, initial/ending readings, and verify no visible sediment or salinity; photo evidence.

Spreading and Mixing

9. Pre-pulverize subgrade to design depth with reclaimer; measure depth at test pits using ruler/painted probe; acceptance: depth within ±10 mm of design.
10. Spread binder uniformly with calibrated spreader; collect three pan catches per lane; acceptance: pan-to-pan variation within ±10% and no visible streaks; attach photos.
11. Perform first mixing pass to full depth; record machine model, pass speed, and drum settings; acceptance: no untreated zones, binder lumps ≤ 25 mm; photos of cut face.
12. For lime treatment, implement mellowing as per approved plan; keep surface moist and track start/finish times; acceptance: dust suppressed and uniform reaction; log entries.

Moisture Conditioning

13. Measure moisture after mixing using oven or speedy tester; acceptance: OMC −1% to +2% before compaction; record readings, location, and tester ID.
14. Apply water via controlled spray bars to correct moisture; avoid runoff and ponding; re-mix and re-test; acceptance: no standing water; upload photos and readings.
15. Verify pulverization: sample mixed soil; acceptance: 100% passing 25 mm and ≥60% passing 4.75 mm sieve; photo of field sieve results.
16. Confirm pre-compaction surface shape; check crossfall with level and straightedge; acceptance: ≤10 mm deviation under a 3 m straightedge; photos uploaded.

Compaction and Finishing

17. Compact with specified rollers (padfoot then smooth drum); record roller IDs, ballast, and pass count; acceptance: ≥95% of MDD achieved; attach nuclear gauge photos.
18. Perform density testing at ≥1 test per 400 m² per lift; document wet density, moisture, dry density, and %MDD; rework and re-test failing areas.
19. Trim and finish surface to line and grade; acceptance: final grade within ±15 mm and crossfall within design ±0.5%; attach survey shots.
20. Apply curing protection (light water spray or approved seal) to prevent drying/carbonation; acceptance: continuous coverage without dusting; record method and rate.

Quality Control Testing

21. Field pH check for lime-treated mix using calibrated pH meter; acceptance: slurry pH ≥ 12 indicating adequate lime presence; photo of meter display.
22. Sample mixed material for laboratory UCS at specified ages (e.g., 7 days); complete chain-of-custody; acceptance: results meet target strength per approved specifications.
23. Monitor quicklime reaction exotherm with infrared thermometer within first hour; acceptance: stabilized layer temperature at least 5 °C above ambient; log readings.
24. Restrict traffic during cure; install barriers and signage; acceptance: no rutting or surface disturbance >10 mm; daily photos and superintendent sign-off.

Mix Design Control and Binder Application

Successful stabilization begins with a verified mix design and tight control of binder placement. Confirm the lime or cement type, the target percentage by dry soil mass, treatment depth, and the target strength age per approved project specifications and authority requirements. Ensure the reclaimer can consistently achieve full-depth mixing without leaving untreated seams. Calibrate the spreader using a weighbridge and pan catches so the application rate stays within ±5% of the target. For lime, a planned mellowing interval promotes the pozzolanic reaction and improves workability, but surface drying must be prevented. Use the latest modified Proctor data to anchor all moisture and density decisions. Well-documented lot numbers, COAs, and equipment calibration records safeguard traceability and reduce disputes. Uniformity is the goal: consistent dosage and depth are the foundation for reliable strength gain and stiffness development across the entire treated platform.

Use weighbridge and pan catches to calibrate spread.
Record binder lots, tickets, and COAs with photos.
Target uniform mixing depth across the treatment width.
Plan and manage mellowing for lime treatments.
Tie field targets to current Proctor data.

Moisture, Pulverization, and Compaction to Density

Moisture management drives both reactivity and compaction success. After mixing, test moisture with an oven or speedy tester; aim for OMC −1% to +2% before compaction. Correct with controlled spray bars, then re-mix and re-test. Confirm pulverization so binder can react and coat fines: use a field sieve to verify 100% passing 25 mm and at least 60% passing 4.75 mm. Compact with the specified rollers, tracking passes, ballast, and vibration settings. Confirm density with nuclear gauge testing at least once per 400 m² per lift to achieve ≥95% of MDD, reworking weak zones immediately. Maintain surface planarity before and after compaction; straightedge and level checks prevent thin pavement risks later. Document all readings and upload photos of gauges and test pits to create an auditable record.

Moisture within OMC range before compaction.
Verify pulverization with field sieve checks.
Achieve ≥95% MDD across each test lot.
Rework and re-test failing areas promptly.
Maintain straightedge tolerances throughout.

Curing, Protection, and Strength Verification

After compaction, protect the treated layer from drying and carbonation. Apply light water sprays or an approved curing seal to maintain moisture. Limit traffic until curing is complete and the surface shows no rutting or disturbance. For lime-treated soils, a quick field pH check (≥12) indicates adequate lime availability; for both binders, submit laboratory unconfined compressive strength results at the specified age to confirm performance. When quicklime is used, monitor the exothermic reaction with an infrared thermometer to verify active hydration. Keep all evidence linked: curing logs, traffic control photos, lab reports, and sign-offs. This disciplined close-out prevents early surface degradation and ensures the stabilized subgrade delivers the target stiffness and bearing capacity for subsequent layers, without venturing into pavement design decisions.

Maintain moisture with spray or curing seal.
Control traffic to prevent rutting during cure.
Verify pH for lime and UCS in the lab.
Log infrared temperature for quicklime reaction.
Archive reports with traceable sign-offs.

How to Use This Interactive Checklist

Preparation: Gather approved mix design, Proctor data, COAs, calibrated scale records, nuclear gauge, moisture tester, pH meter, infrared thermometer, sieve kit, straightedge, survey gear, cameras, PPE, and traffic control materials.
Create a project session: enter location, lot boundaries, design depth, target binder percentage, and required density/strength; assign inspectors and contractors with notification permissions.
Using the Interactive Checklist: start interactive mode, tick items as completed, attach photos, readings, and files; @mention responsible parties to resolve comments in real time.
Capture evidence in context: log spreader calibration, pan catches, moisture tests, density results, pH readings, and curing logs; use time-stamped photos and GPS-tagged entries.
Monitor progress: filter by group (documentation, materials, mixing, moisture, compaction, testing) and track status to close open non-conformances before work advances.
Export and share: generate commentable reports and export as PDF/Excel; the QR code on each export links back to the authenticated record set.
Sign-Off: collect digital signatures from contractor, inspector, and owner’s representative; lock the record and archive with version control for future audits.

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Subgrade Stabilization with Lime/Cement

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Noah Schneider RenewableNoah

Dec 17, 2025

151

FAQ

Question: How do I choose between lime and cement for subgrade stabilization?

Choose based on soil plasticity, sulfates, and moisture. Lime is effective for high-plasticity clays and reduces swell via cation exchange and pozzolanic reactions. Cement suits granular or low-plasticity soils and provides rapid early strength. Verify with laboratory mix design trials and adopt the binder and dosage that meet target strength and durability per approved project specifications.

Question: What weather limits apply when stabilizing with lime or cement?

Avoid freezing conditions, heavy rain, and strong winds that cause dusting or wash-off. Aim for air temperatures between about 5–38 °C and a dry weather window covering application, mixing, and initial cure. If unexpected rain occurs, suspend work, protect the area, and re-test moisture, pulverization, and density before proceeding.

Question: Why is moisture so critical, and what range should I target?

Moisture controls both chemical reactions and compaction efficiency. Too dry limits reaction and density; too wet softens and delays strength gain. Use the latest modified Proctor to guide field targets. A practical acceptance is OMC −1% to +2% before compaction, confirmed with reliable moisture tests and supported by density verification.

Question: What field checks confirm lime treatment is reacting as intended?

Look for uniform mixing and suppressed dust, take a pH reading of a slurry sample (≥12 suggests adequate lime), and observe a temperature rise when using quicklime. Maintain moisture during mellowing. These checks complement laboratory strength tests to confirm that the pozzolanic reaction proceeds effectively across the treated zone.

Question: How soon can I allow traffic on the stabilized layer?

Limit traffic until compaction is verified and initial curing stabilizes the surface. Keep construction vehicles off if rutting or surface disturbance exceeds about 10 mm. Follow the curing duration and opening criteria stated in the approved project specifications, and document any early access with additional density and condition checks.