ASTM A615 reinforcement is required to be marked with what designation?

• A. A
• B. B
• C. C
• D. S

Answer: (D)

Marking on reinforcing bars identifies the material and the standard it must meet. For ASTM A615 reinforcing bars, the designation that is stamped is the letter S, which signifies reinforcing steel per this standard. This simple mark helps inspectors and crews confirm they’re using the correct reinforcing material, ensuring it complies with A615. In practice you’ll also see the grade and the manufacturer’s mark, but the required designation that identifies the bar as reinforcing steel under this standard is S.