Answer :
Final answer:
Portland cement and normal-weight aggregate must adhere to a) ASTM C150 and ASTM C33 standards, respectively, ensuring the quality and suitability of these materials for construction purposes.
Explanation:
In the context of materials used for concrete construction, the correct standards for Portland cement and normal-weight aggregate are critical. Portland cement must conform to ASTM C150, and normal-weight aggregate must conform to ASTM C33 in all concrete applications. ASTM C150 specifies the specification for Portland cement, which includes requirements for chemical composition, physical properties, and other important criteria that ensure the cement's quality and suitability for various construction purposes. On the other hand, ASTM C33 covers the standards for the quality, size, grading, and other aspects of normal-weight aggregates such as sand, gravel, or crushed stone, which play a crucial role in the strength and durability of concrete.
Therefore, the correct answer is: Portland cement must conform to ASTM C150, and normal-weight aggregate must conform to ASTM C33 in all concrete.