What size are the test cylinders for testing the strength of concrete?

What size are the test cylinders for testing the strength of concrete?

• A. 6 inches in diameter and 12 inches high
• B. 4 inches in diameter and 8 inches high
• C. 8 inches in diameter and 16 inches high
• D. 12 inches in diameter and 24 inches high

Answer: (A)

Concrete strength testing uses cylinders sized 6 inches in diameter and 12 inches tall. This size, with a height-to-diameter ratio of 2:1, provides stable, repeatable failure behavior and minimizes end effects, which helps the test reflect the material’s true compressive strength. When the cylinder is loaded to failure, the strength is calculated by dividing the load at failure by the cross-sectional area (pi times the radius squared). While smaller cylinders like 4x8 inches can be used in some quick checks, the standard specification in codes and practice for 28-day compressive strength is the 6x12 inch cylinder.

Concrete strength testing uses cylinders sized 6 inches in diameter and 12 inches tall. This size, with a height-to-diameter ratio of 2:1, provides stable, repeatable failure behavior and minimizes end effects, which helps the test reflect the material’s true compressive strength. When the cylinder is loaded to failure, the strength is calculated by dividing the load at failure by the cross-sectional area (pi times the radius squared). While smaller cylinders like 4x8 inches can be used in some quick checks, the standard specification in codes and practice for 28-day compressive strength is the 6x12 inch cylinder.