How many cylinder specimens are typically produced from a batch to test strength, and how should they be identified?

• A. A minimum of two or more per batch; label cylinders with batch and pour date and assign a unique ID to each cylinder.
• B. A fixed two cylinders per batch, with no labeling.
• C. Ten cylinders per batch, but only the batch ID is required.
• D. One cylinder per batch, labeled by color.

Answer: (C)

The main point is that strength testing uses more than one cylinder from each concrete batch, and every cylinder must be clearly identified so its test results can be traced back to the exact batch and pour date.

In FDOT practice, you generate several cylinders from each batch to get a representative strength result, and you label each cylinder with the batch number, the pour date, and a unique cylinder ID. This combination ensures you can tie the results to the specific batch and curing history, and you can track which cylinder was tested at which age (for example, 7 days and 28 days).

Relying on a single cylinder or not providing unique IDs undermines traceability and the ability to average results across multiple specimens. Producing an adequate number of cylinders (commonly six per batch in many specifications) and giving each cylinder its own identifying information keeps testing reliable and traceable.