ACI TEST C138 QUESTIONS WITH CORRECT
ANSWERS 2025/2026
The diameter of the tamping rod used in the test method is _____. - CORRECT ANSWER -5/8"
±1/16"
What is the required shape of the tamping end of the rod - CORRECT ANSWER -hemispherical
tip
What is the minimum required frequency of the vibrator used in this method? - CORRECT
ANSWER -150 Hz
The OD of the vibrating element must be _____ to _____ - CORRECT ANSWER -0.75", 1.5"
A plastic container can be used for the measure in this method. (T/F) - CORRECT ANSWER -F
The minimum thickness of a metal strike-off plate is _____ and the minimum thickness of a
glass or acrylic strike-off plate is _____. The width must be _____ greater than the diameter of
the measure. - CORRECT ANSWER -1/4", 1/2", 2"
Mallet size for measures ≤ 0.5 cf = _____
Mallet size for measures > 0.5 cf = _____ - CORRECT ANSWER -1.25± 0.5 pounds,
2.25 ± 0.5 pounds
Measures other than air meter bowls used for this test must conform to ASTM _____. -
CORRECT ANSWER -C29
ANSWERS 2025/2026
The diameter of the tamping rod used in the test method is _____. - CORRECT ANSWER -5/8"
±1/16"
What is the required shape of the tamping end of the rod - CORRECT ANSWER -hemispherical
tip
What is the minimum required frequency of the vibrator used in this method? - CORRECT
ANSWER -150 Hz
The OD of the vibrating element must be _____ to _____ - CORRECT ANSWER -0.75", 1.5"
A plastic container can be used for the measure in this method. (T/F) - CORRECT ANSWER -F
The minimum thickness of a metal strike-off plate is _____ and the minimum thickness of a
glass or acrylic strike-off plate is _____. The width must be _____ greater than the diameter of
the measure. - CORRECT ANSWER -1/4", 1/2", 2"
Mallet size for measures ≤ 0.5 cf = _____
Mallet size for measures > 0.5 cf = _____ - CORRECT ANSWER -1.25± 0.5 pounds,
2.25 ± 0.5 pounds
Measures other than air meter bowls used for this test must conform to ASTM _____. -
CORRECT ANSWER -C29
