9.3 Documentation and Report Accuracy

A Field Report Is a Chain of Evidence

A field report must let someone reconstruct what concrete was sampled, where it came from, when it was tested, which methods were used, what was measured, and who recorded it. The report is the bridge between the truck on site and the strength break in the lab 28 days later. If any link is missing, the result becomes an orphan number that cannot defend or condemn the concrete.

The first anchor is the ASTM C94 delivery (batch) ticket, which the producer must furnish with each load. The technician records its number and cross-checks the mix. Required C94 ticket information includes:

Record Raw Facts, Not Just Conclusions

Good documentation captures the raw observations and the corrections separately so the math can be checked. For air content by C231, that means recording the gauge reading and the aggregate-correction factor, then the corrected air. For density by C138, record the measured mass, the measure's mass and volume, and the calculated density and yield. Recording only the final number hides errors and prevents review.

A complete field report typically captures:

• Identification: project, date, ticket number, truck number, mix ID, placement location, and sample time.
• Fresh results: temperature (°F), slump (in.), air (%), density (lb/ft³), and yield, with the method (C231 vs C173) noted.
• Raw data and corrections: gauge readings, correction factors, container mass and volume, and rod/vibration method.
• Specimens: number molded, mold IDs, consolidation method, and initial-curing conditions.
• Conditions and notes: ambient temperature, weather, any added water, and any invalid or repeated test with its reason.

Writing results while the work is fresh avoids transcription error and memory loss; numbers reconstructed an hour later are not trustworthy.

Specimens and Objectivity

Specimen documentation is not clerical busywork — it is the only thing that makes a 28-day break meaningful. Each cylinder mold is labeled with permanent identity (project, set number, date, and a unique mark) and the report records how many were molded, the consolidation method, and the initial-curing temperature range required by C31 (generally 60–80 °F for standard-strength concrete, 68–78 °F for concrete specified above 6,000 psi). A perfect strength result on an unlabeled cylinder still tells the engineer nothing.

Finally, accurate reports separate measured results from opinion. The technician writes "slump 6.5 in.; specified 4 ± 1 in.; producer notified at 10:42," not "the load was bad." Stating a fact and a notification time is objective and defensible; characterizing the load is an acceptance judgment the Grade I technician is usually not authorized to make. The report shows what happened, when, and to whom it was communicated, without personal blame.

Cross-Checking the Ticket and Closing the Loop

The delivery ticket and the field report are checked against each other. The technician confirms the mix identification on the ticket matches the concrete specified for that placement, notes the time batched so the discharge time limit can be tracked, and records any water added — both at the plant and, critically, any tempering water added on site. Under ASTM C94 there is no default 90-minute discharge limit; the purchaser (or, if silent, the producer) states the limit on the ticket, so the technician must read the actual number rather than assume 90 minutes or 300 revolutions.

Logging batch time and arrival time lets the technician verify discharge is completed in time.

Units, Significant Figures, and Legibility

Reporting precision matters. ASTM methods specify reporting resolution, and the technician should honor it:

Numbers are written legibly and in ink, corrections are struck through with a single line (not erased or overwritten) and initialed, and the technician signs the report. A report that is illegible, over-rounded, or unsigned weakens the chain of evidence even when the underlying tests were valid. Finally, the report is transmitted to the laboratory and the responsible party promptly, so strength specimens can be matched to their fresh-property data and any out-of-spec fresh result is acted on before more concrete is placed. Closing this loop — field to lab to engineer — is what turns a stack of readings into usable quality records.

One more documentation discipline is contemporaneous recording. Each value is written the moment it is read, not reconstructed from memory after the placement; the human memory for numbers degrades quickly under jobsite pressure, and a value recalled an hour later is not defensible. If a technician must testify or defend a result later, the report that was filled in beside the truck — with raw readings, corrections, times, and notifications — carries far more weight than any after-the-fact summary, because it shows the work as it actually happened.