Which ASTM standard evaluates SCC's ability to pass through a simulated reinforcing cage?

The correct choice evaluates the ability of self-consolidating concrete (SCC) to flow and pass through congested reinforcement, which is a critical property for its performance in reinforced structures. ASTM C1621 specifically addresses the test method for observing the passing ability of SCC through a simulated reinforcing cage while ensuring that the concrete maintains its workability and does not segregate.

This standard includes assessment techniques that measure not only the flow characteristics of the concrete but also its capability to navigate around obstacles typically found in reinforced structures, ensuring that the concrete effectively fills the mold or space without leaving voids. This ability is essential for the integrity and strength of concrete structures, as any inability to pass through reinforcement can lead to weak spots and increased risk of structural failure.

The other options listed pertain to different aspects or types of testing related to concrete but do not specifically address the passing ability through reinforcement. For instance, ASTM C494 relates to chemical admixtures for concrete, ASTM C171 deals with the measurement of temperature in fresh concrete, and ASTM C979 is focused on the use of color in concrete. Therefore, these standards do not assess the critical performance characteristic of SCC evaluated by ASTM C1621.