8.6 Transport, Lab Handoff, Reporting, and Common Failures

Transport and Documentation Complete the Specimen Story

C31 specimens leave the technician's hands with a history. The laboratory sees the mold, label, and report, but it cannot see every field exposure unless the technician documents it. Transport and reporting complete the specimen story by preserving the physical sample and explaining how it was made, cured, moved, and handed off.

Specimens should remain undisturbed during the initial curing period required by the method. When they are transported, they must be protected from jarring, freezing, overheating, drying, and physical damage. Current C31 materials include limits for timing and transport duration, including prompt movement to the laboratory after initial curing and a maximum transport time concept. The exam-level point is that transport is controlled, not casual.

Cylinders should be cushioned and kept upright when required by the project procedure. Beams need even more support because they can crack, twist, or dry. Specimens should not be thrown into a truck bed, left in direct sun, or stacked in a way that deforms molds. If molds are removed before transport as allowed by the procedure, specimens still need moisture and damage protection.

Reporting should include project name, location, concrete supplier or truck information when required, sample location, batch or ticket identifiers, specimen size and type, number of specimens, method of consolidation, curing condition, date and time of molding, and the technician identity. Project forms may require more detail, but missing core information weakens the result.

Deviations should be documented, not hidden. If a curing box went outside the required temperature range, if transport was delayed, if a beam was bumped, or if a specimen label was damaged and corrected, the record should say so. A strength result with a known curing deviation may still be useful, but it must be interpreted with that history. An undocumented deviation can create a dispute later.

Common C31 failure points:

• Specimens made from an unrepresentative or delayed sample.
• Wrong mold size for aggregate or test purpose.
• Poor consolidation, especially at cylinder edges or beam corners.
• No prompt moisture protection after finishing.
• Initial curing outside required temperature limits.
• Rough transport, excessive transport time, or lost labels.
• Reports missing curing category, specimen ID, or molding time.

For the ACI performance exam, speak through the handoff logic. Identify specimens, protect them, state the curing method, and explain that they will be transported and delivered under C31 controls. For the written exam, watch for answers that treat transport as ordinary hauling. C31 transport is part of the test method because it preserves the specimen until final curing and testing.