ACI Written Exam Questions With Verified
Answers.
Collecting a representative sample of concrete to be tested is as important as executing the test
methods to obtain - answeraccurate results
This practice covers sampling from four types of equipment, which are - answerstationary
mixers, paving...
Collecting a representative sample of concrete to be tested is as important as executing the test
methods to obtain - answer✔accurate results
This practice covers sampling from four types of equipment, which are - answer✔stationary
mixers, paving mixers, revolving mixers, continuous mixers
The elapsed time between obtaining the first and final portions of a composite sample shall not
exceed - answer✔15 minutes
Portions of a composite sample shall be thoroughly remixed before beginning tests on the
sample. T/F - answer✔True
Start tests for slump, temperature, and air content within how many minutes after obtaining the
final portion of the composite sample? - answer✔5 minutes
Start molding specimens for strength tests within how many minutes after fabricating the
composite sample? - answer✔15 minutes
The concrete sample must be protected from contamination and - answer✔rapid evaporation
The minimum size sample for making strength test specimens is - answer✔1 cf
When sampling from a stationary mixer, the batch must be sampled at __ or more regularly
spaced intervals during discharge of the middle portion of the batch. - answer✔2
When sampling from a paving mixer, obtain samples from at least __ different portions of the
pile and combine them into one composite sample for test purposes. - answer✔5
When sampling from a revolving truck mixer, sample the concrete by collecting __ or more
portions taken at regularly spaced intervals during discharge of the middle portion of the batch. -
answer✔2
Concrete samples from a truck mixer must be obtained before any water or admixtures are added
to the mixer at the job site. T/F - answer✔False
When the concrete contains aggregate larger than that permitted for a particular test method, the
sample of concrete must be ___ before making the test. - answer✔wet-screened
When the concrete contains aggregate larger than allowed for the slump test, the large aggregate
must be ___ - answer✔wet screened over 1-½"
The mold for making the slump test is in the shape of - answer✔the frustum of a cone
The height of the slump mold is - answer✔12"
The interior surface of the slump mold is allowed to have minor irregularities. T/F -
answer✔False
For use in the slump test, the tamping end or both ends of the tamping rod must be -
answer✔rounded to a hemispherical tip
The slump mold should be in a dry condition before beginning the test. T/F - answer✔False
The surface on which the slump mold will be placed must be - answer✔flat, level, damp,
nonabsorbent, and rigid
The slump mold is filled in __ layers. - answer✔3
Each layer should fill approximately __ the volume of the mold. - answer✔1/3
Rod each layer __ times uniformly over the cross section with the rounded end of the rod. -
answer✔25
How deep should the tamping rod penetrate into each layer? - answer✔Rod each layer
throughout its depth; on the second and final layers, the rod should penetrate into the previous
layer approximately 1"
What must be done if the concrete drops below the top of the slump mold while the top layer is
being rodded? - answer✔Add additional concrete to keep an excess of concrete above the told of
the mold.
Prior to lifting the mold, concrete must be removed from - answer✔the area surrounding the base
of the mold.
After the final rodding, the sides of the slump mold should be tapped lightly with the tamping
rod. T/F - answer✔False
When raising the slump mold, it should not be rotated or twisted. T/F - answer✔True
How much time is allowed for lifting the slump mold? - answer✔5 +/- 2 seconds
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