ASTM C33 pertains specifically to which type of aggregate?

ASTM C33 is the standard specification for concrete aggregates, and it specifically addresses normalweight aggregates. Normalweight aggregates are typically sand, gravel, or crushed stone that have a density of approximately 140 to 150 pounds per cubic foot or more. These aggregates are crucial for producing concrete with desirable strength and durability characteristics.

The standard outlines the requirements for the grading, quality, cleanliness, and other properties of normalweight aggregates to ensure they are suitable for use in concrete. This is essential because the type and quality of aggregates can significantly affect the performance of the concrete mix in terms of workability, strength, and long-term durability.

In contrast, water, calcium chloride, and steel fiber reinforcement do not fall under the category defined by ASTM C33, as they serve different functions in the concrete mix or construction process. Water is a vital ingredient in the hydration process, calcium chloride is sometimes used as an accelerator in concrete mixes, and steel fiber reinforcement is utilized to enhance the tensile properties and crack resistance of concrete but is not classified as an aggregate.