A field QA/QC program documents that every item of work meets specification before it is covered or accepted. Required documentation includes: inspection checklists for each work type signed by the responsible inspector; compaction test logs with pass/fail for all fill and backfill; grade verification logs; material certifications; and nonconformance reports (NCRs) with documented corrective action for every failing result. All records must be completed at the time of work.
QA vs QC: The Practical Distinction
Quality Control (QC) is what the contractor does to verify their own work — grade checks, compaction tests, joint inspections. You control it and document it.
Quality Assurance (QA) is what the owner, engineer, or agency does to verify that your QC program is working — independent density testing, grade surveys, documentation audits. They assure themselves your QC is real.
On public projects (DOT, municipal sewer), the agency runs their own QA testing alongside your QC. If your tests pass and their independent tests fail, your documentation is part of the investigation. Consistent, honest documentation of both passes and failures builds credibility.
QC Documentation Requirements by Work Type
Earthwork and Compaction
- Proctor compaction tests (one per material per borrow source)
- Field density tests at required frequency with station/offset locations, lift numbers, and pass/fail
- Any NCR for failed tests with corrective action and retest results
Pipe Installation and Grade
- As-built invert elevations at every structure and at 25–50 ft intervals for gravity pipe
- Grade verification table: design vs measured vs deviation vs pass/fail
- Pipe material certifications and ASTM compliance documents
- Pressure test record for water mains (or vacuum test for sewer)
Structural Concrete and Paving
- Concrete mix design submittal and approval
- Batch tickets for every load placed
- Slump and air content test at point of placement (per ACI 305)
- Cylinder breaks at 7 and 28 days
- Concrete subgrade grade verification (ACI 117 tolerance)
The Nonconformance Report (NCR)
When a test or inspection fails, an NCR is the formal record. An NCR must document:
- What failed (specific test, location, and date)
- What the specified requirement was
- What the actual result was
- Root cause (if known)
- Corrective action taken and who authorized it
- Verification test result after correction
- Close-out date and signature
Never close an NCR without a documented passing verification test. Open NCRs at project close-out are red flags for inspectors and owners.
Field Inspection Checklists
For each major work phase, complete a pre-work and post-work inspection checklist. Examples:
- Trench pre-pipe inspection: Trench bottom to design depth ✓, bedding placed ✓, trench protection in place ✓, water pumped out ✓
- Pipe installation: Pipe material correct ✓, joints assembled per spec ✓, laser/level grade check at every joint ✓, as-built shot logged ✓
- Backfill pre-compaction: Lift thickness ≤ 8 in ✓, material approved ✓, no debris in trench ✓
Log all QC documentation in Gradelog alongside grade verification and compaction tests for a single, complete project record. See also: Daily Field Report Best Practices.