ACI Certification Exam
According to ASTM C 138 what is the air content (in percent) of the following concrete batch?
Theoretical Density = 168 lb/cuft Density = 158 lb/cuft - ANS-6.0% = [(168-158)/168] x 100
According to ASTM C 138 what is the density of the following concrete batch?
Mass of Measure 7.4 lbs
Mass of Measure w/ Concrete 44.5 lbs
Volume of Measure .254 CF - ANS-146.06 lb/cf = (44.5-7.4)/0.254
According to ASTM C 138 what is the relative yield of the following 5 cubic yard concrete batch?
Mass of all materials batched 19,775 lbs
Density of Concrete 146 lbs/cuft - ANS-1.003 = (19775/(146 x 27))/5
According to ASTM C 138 what is the yield of the following concrete batch in cubic yards? Mass
of Materials Batched = 12645 lbs Density of concrete = 156 lbs/cuft - ANS-3.00 CY =
(12,645/(156 x 27))
After consolidation of the final layer, the concrete is ½ inch above the top of the measure, what
should be done? - ANS-remove excess concrete with a scoop or trowel
After strike off of the measure used to determine density, a small quantity of concrete may be
added to correct a deficiency? - ANS-False
ASTM 173 is appropriate for testing concretes containing lightweight aggregates. - ANS-True
ASTM 173 specifies a minimum time requirement for inverting and agitating the meter to free
concrete from the base. - ANS-True
ASTM 173 specifies that at the very end of the test the tester must make sure that there are
portions undisturbed in the bottom of the bowl, if so the test is valid. - ANS-False
ASTM 173 specifies that the bowl is filled in 3 lifts. - ANS-False
ASTM C 1064 - ANS-Temperature of freshly mixed concrete
ASTM C 1064 defines the maximum recommended temperature for concrete. - ANS-False
ASTM C 138 - ANS-Density, Unit Weight, Yield, and Air Content (Gravimetric) of Concrete
, ASTM C 143 - ANS-Slump of hydraulic cement
ASTM C-172 - ANS-Sampling
ASTM C172 covers sampling from stationary, paving and truck mixers, and from agitating and
non-agitating equipment used to transport central-mixed concrete. - ANS-True
ASTM C173 - ANS-Standard Test Method for Air Content of Freshly Mixed Concrete by the
Volumetric Method
ASTM C231 - ANS-Air Content of Freshly Mixed Concrete by the Pressure Method
ASTM C31 - ANS-Standard Practice for Making and Curing Concrete Test Specimens in the
Field
At the end of the pressure method procedure, how is the pressure released from the Type B air
meter? - ANS-Opening both petcocks
Each temperature-measuring device should be calibrated ________, or whenever there is a
question of _________. - ANS-Annually, Accuracy
Field cured specimens can be used to determine whether a structure is capable of being put
into service, and can take the place of standard cured specimens. - ANS-False
For concrete mixtures with a specified strength greater than 6000 psi the initial curing
temperature should be - ANS-68-78 degrees F
How do you regulate the rate of discharge of the batch from the revolving truck drum mixer or
agitator? - ANS-By the rate of revolution of the drum
If rodding is the method of consolidation being used in C138, the measure must be filled in how
many layers? - ANS-3
If the aggregate correction factor for a given source of fine and coarse aggregate is found to be
0.2% in a pressure air meter, and an air content value of 5.0% is read on the gauge of the same
air meter containing concrete with the same aggregate, what is the correct air content? -
ANS-4.8% (5.0-.2)
If the aggregate is too large, it must be ________________. - ANS-Wet sieved over the 1 1/2"
sieve
If the sample is vibrated the duration of vibration should last ___________. - ANS-Until the
surface concrete is smooth
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