ACI- Concrete Field-Testing
Technician Exam with Complete
Solutions
Q1. Start molding specimens for strength tests within 30 minutes after fabricating the
composite sample.
A. True
B. False - ANS-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 - ANS-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 - ANS-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 - ANS-A. True
ASTM C172- Para (6.1)
Q5. The composite sample should not be remixed before beginning any tests.
,A. True
B. False - ANS-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 - ANS-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 - ANS-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 - ANS-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 - ANS-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 - ANS-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 - ANS-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
D. None of the above - ANS-B.
Passing a receptacle completely through the discharge steam or by completely diverting
the discharge into the sample container.
ASTM C172- Para (5.2.3).
Technician Exam with Complete
Solutions
Q1. Start molding specimens for strength tests within 30 minutes after fabricating the
composite sample.
A. True
B. False - ANS-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 - ANS-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 - ANS-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 - ANS-A. True
ASTM C172- Para (6.1)
Q5. The composite sample should not be remixed before beginning any tests.
,A. True
B. False - ANS-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 - ANS-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 - ANS-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 - ANS-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 - ANS-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 - ANS-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 - ANS-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
D. None of the above - ANS-B.
Passing a receptacle completely through the discharge steam or by completely diverting
the discharge into the sample container.
ASTM C172- Para (5.2.3).
