ACI CERTIFICATION EXAMINATION TEST
2026 COMPREHENSIVE Q&A STUDY GUIDE
◉How deep should the tamping rod penetrate into each layer?
C143/C143M-15a. Answer: Rod each layer throughout its depth; on
the second and final layers, the rod should penetrate into the
previous layer approximately 1 in. [25 mm].
C143/C143M-15a
◉When rodding the bottom layer, the tamping rod must be _____ to
uniformly distribute the strokes.
C143/C143M-15a. Answer: Slightly inclined
C143/C143M-15a
◉What must be done if the concrete drops below the top of the
slump mold while the top layer is being rodded?
,C143/C143M-15a. Answer: Add additional concrete to keep an
excess of concrete above the top of the mold at all times
C143/C143M-15a
◉Prior to lifting the mold, concrete must be removed from _____.
C143/C143M-15a. Answer: The area surrounding the base of the
mold
C143/C143M-15a
◉After the final rodding, the sides of the slump mold should be
tapped lightly with the tamping rod. True or False?
C143/C143M-15a. Answer: False.
C143/C143M-15a
◉When raising the slump mold, it should not be rotated or twisted,
True or False?
C143/C143M-15a. Answer: True.
,C143/C143M-15a
◉How much time is allowed for lifting the slump mold?
C143/C143M-15a. Answer: 5 ± 2 seconds
C143/C143M-15a
◉The measurement for slump is made from the top of the mold to
what point of the concrete specimen?
C143/C143M-15a. Answer: The displaced original center of the top
surface of the specimen.
C143/C143M-15a
◉The slump of the concrete is measured and reported to the nearest
_____.
C143/C143M-15a. Answer: 1/4 in. [5 mm].
, C143/C143M-15a
◉How much time is allowed to conduct the slump test from
beginning to completion?
C143/C143M-15a. Answer: 2 1/2 minutes
C143/C143M-15a
◉The diameter of the tamping rod used in this test method is______.
C138/C138M-17a. Answer: 16 mm 5/8 in. ± 2 mm 1/16 in.
C138/C138M-17a
◉What is the required shape of the tamping end of the rod?
C138/C138M-17a. Answer: Rounded to a hemispherical tip
C138/C138M-17a
2026 COMPREHENSIVE Q&A STUDY GUIDE
◉How deep should the tamping rod penetrate into each layer?
C143/C143M-15a. Answer: Rod each layer throughout its depth; on
the second and final layers, the rod should penetrate into the
previous layer approximately 1 in. [25 mm].
C143/C143M-15a
◉When rodding the bottom layer, the tamping rod must be _____ to
uniformly distribute the strokes.
C143/C143M-15a. Answer: Slightly inclined
C143/C143M-15a
◉What must be done if the concrete drops below the top of the
slump mold while the top layer is being rodded?
,C143/C143M-15a. Answer: Add additional concrete to keep an
excess of concrete above the top of the mold at all times
C143/C143M-15a
◉Prior to lifting the mold, concrete must be removed from _____.
C143/C143M-15a. Answer: The area surrounding the base of the
mold
C143/C143M-15a
◉After the final rodding, the sides of the slump mold should be
tapped lightly with the tamping rod. True or False?
C143/C143M-15a. Answer: False.
C143/C143M-15a
◉When raising the slump mold, it should not be rotated or twisted,
True or False?
C143/C143M-15a. Answer: True.
,C143/C143M-15a
◉How much time is allowed for lifting the slump mold?
C143/C143M-15a. Answer: 5 ± 2 seconds
C143/C143M-15a
◉The measurement for slump is made from the top of the mold to
what point of the concrete specimen?
C143/C143M-15a. Answer: The displaced original center of the top
surface of the specimen.
C143/C143M-15a
◉The slump of the concrete is measured and reported to the nearest
_____.
C143/C143M-15a. Answer: 1/4 in. [5 mm].
, C143/C143M-15a
◉How much time is allowed to conduct the slump test from
beginning to completion?
C143/C143M-15a. Answer: 2 1/2 minutes
C143/C143M-15a
◉The diameter of the tamping rod used in this test method is______.
C138/C138M-17a. Answer: 16 mm 5/8 in. ± 2 mm 1/16 in.
C138/C138M-17a
◉What is the required shape of the tamping end of the rod?
C138/C138M-17a. Answer: Rounded to a hemispherical tip
C138/C138M-17a
