What is the standard practice for sampling freshly mixed concrete according to ASTM C172/C172M?

The correct response identifies the specific standard dedicated to the process of collecting samples of freshly mixed concrete, which is essential for ensuring the quality and consistency of the mix. ASTM C172/C172M explicitly outlines the procedures, techniques, and requirements necessary to obtain samples that accurately represent the bulk of the concrete being produced.

This standard is critical in various applications, ensuring that results from subsequent tests—such as assessing the concrete's strength, workability, and other performance characteristics—are based on reliable and representative samples. The intention behind this practice is to minimize variability and ensure high standards in concrete quality assessment.

The other options, while related to concrete practices, do not focus on the sampling process itself. They pertain to other aspects of concrete quality or management, making them irrelevant when the specific context of sampling procedures is required.