What type of admixtures does ASTM C494 address?

ASTM C494 is a standard specification that specifically addresses chemical admixtures for use in concrete. The correct answer, which focuses on plasticizers and water reducers, aligns with the primary purpose of ASTM C494. These admixtures are designed to improve the workability of concrete, reduce water content without affecting the workability, and enhance strength and durability.

By utilizing these admixtures, concrete producers can achieve a desired consistency while maintaining or even reducing the overall water-to-cement ratio, which is critical for achieving optimal strength and performance in concrete mixes. This specification also includes requirements for performance, compositional and material properties, and testing methods necessary for effective use.

Options like corrosion-inhibiting admixtures, pigments for integrally colored concrete, and curing compounds do not fall under the scope of ASTM C494, as each of these categories is addressed by other specifications or standards. Thus, ASTM C494 specifically focuses on enhancing the properties of concrete through water reducers and plasticizers, making that choice the most accurate representation of the document's purpose.