ACI Concrete Field-Testing Technician -
Grade 1 Exam Review | 100% Correct
Answers | Verified | Latest 2024 Version
Q1. Start molding specimens for strength tests within 30 minutes after fabricating the composite sample.
A. True
B. False - ✔✔B. False
ASTM C172 -Para (4.1.2) - Start molding.
specimens for strength tests within 15 min after fabricating the
composite sample.
Q2. The maximum allowable time between obtaining the first and last portions of the composite sample
may not exceed 5 minutes.
A. True
B. False - ✔✔B. False
ASTM C172 - Para (4.1)- The elapsed time shall not exceed 15 min. between obtaining the first and final
portions of the composite sample.
Q3. The composite concrete sample must be protected from sun, wind, contamination and rapid
evaporation.
A. True
B. False - ✔✔A. True
ASTM C172 - Para (4.1.2)
,Q4. If the concrete contains aggregates larger than those that are appropriate for a size of mold or
equipment used, the sample should be wet sieved before making the test.
A. True
B. False - ✔✔A. True
ASTM C172- Para (6.1)
Q5. The composite sample should not be remixed before beginning any tests.
A. True
B. False - ✔✔B. False
ASTM C172-Para (4.1.1) -The sample shall be combined and remixed with a shovel the minimum amount
necessary to ensure uniformity and compliance with the maximum time limits
Q6. Sampling should normally be performed, as the concrete is discharged from the mixer.
A. True
B. False - ✔✔B. False
ASTM C172-Para (5). NOTE 2—Sampling should normally be performed as the concrete is delivered from
the mixer.
To the conveying vehicle used to transport the
concrete to the forms; however, specifications may require other points of sampling, such as the
discharge of a concrete pump.
,Q7. ASTM Method C172 includes sampling from stationary mixers, paving mixers, truck mixers, agitators,
and non-agitating equipment.
A. True
B. False - ✔✔A. True
ASTM C172- Para (1.1)
Q8. After sampling is completed, start the tests for slump and air content within:
A. 2 ½ minutes
B. 10 minutes
C. 15 minutes
D. None of the above - ✔✔D. None of the above
ASTM C172- Para (4.1.2) Start tests for slump, temperature, and air content within 5 min after obtaining
the final portion of the composite sample.
Q9. In any case, do not obtain samples until:
A. All the water and admixtures have been added to the concrete
B. 200 revolutions of the drum have been obtained
C. ½ of the water has been added
D. None of the above - ✔✔A. All the water and admixtures have been added to the concrete.
ASTM C172- Para (5.2.3). In any case do not obtain samples until after all of the water has been added to
the mixer.
Q10. No samples shall be taken before_________ or after_________ of the batch has been discharged.
, A. 10% or after 90%
B. 20% or after 90%
C. 20% or after 80%
D. None of the above - ✔✔A. 10% or after 90%
ASTM C172- Para (5.2.1).
NOTE 3—No samples should be taken before 10 % or after 90 % of the batch has been discharged.
Due to the difficulty of determining the actual quantity of concrete discharged, the intent is to provide
samples that are representative of widely separated portions, but not the beginning and the end of the
load.
Q11. When strength tests are to be made, the minimum size of the composite sample shall be:
A. ¼ cubic foot
B. 1 cubic foot
C. Any convenient size
D. 1 Wheelbarrow - ✔✔B. 1 cubic foot
ASTM C172- Para (5.1).
Make the samples to be used for strength tests a minimum of 28 L (1 ft3).
Q12. Sample the concrete from the chute of a truck mixer by:
A. Raising chute to stop the flow and scoop concrete from there into the slump cone and cylinder molds
B. Passing a receptacle completely through the discharge steam or by completely diverting the discharge
into the sample container
C. Holding a shovel in the flow and direct half into a bucket
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