ACI Concrete Field-
Testing Technician –
Grade I 150 Advanced
Multiple-Choice Questions
for the September 21–22
Certification Examination
in Columbia, Maryland
Advanced / Hard (Mixed)
Construction professionals, QA/QC technicians, and candidates preparing for
ACI Grade I certification
150 multiple-choice questions with correct answers and detailed rationales
ASTM C1064, C172, C143, C138, C231, C173, and C31
Question
Section Topic ASTM Standard
Numbers
Temperature of Freshly Mixed Hydraulic-
1 C1064/C1064M 1–20
Cement Concrete
, Question
Section Topic ASTM Standard
Numbers
2 Sampling Freshly Mixed Concrete C172/C172M 21–40
3 Slump of Hydraulic-Cement Concrete C143/C143M 41–60
Density (Unit Weight), Yield, and Air Content
4 C138/C138M 61–80
(Gravimetric)
5 Air Content by the Pressure Method C231/C231M 81–100
6 Air Content by the Volumetric Method C173/C173M 101–120
Making and Curing Concrete Test Specimens
7 C31/C31M 121–140
in the Field
8 Integrated Field Scenarios and Calculations Multiple 141–150
What is the minimum submersion depth of the temperature sensing portion of the thermometer
when measuring the temperature of freshly mixed concrete?
A. 2 in. (50 mm)
B. 3 in. (75 mm)
C. 4 in. (100 mm)
D. 6 in. (150 mm)
ASTM C1064 requires the temperature sensing portion of the thermometer to be
submerged a minimum of 3 in. (75 mm) into the concrete to obtain a representative reading.
A field technician places a thermometer into fresh concrete and immediately records the
temperature. Why is this procedurally incorrect?
A. The thermometer must be calibrated before each use.
B. The thermometer must be inserted at a 45-degree angle.
, C. The reading must stabilize before recording, which typically takes 2 to 5 minutes.
D. The thermometer must be placed in the middle of the batch, not the wheelbarrow.
ASTM C1064 requires the technician to wait until the temperature reading stabilizes—
typically 2 to 5 minutes—before recording the temperature.
What is the required temperature reading accuracy for the thermometer used in ASTM C1064?
A. Nearest 2°F (1°C)
B. Nearest 1°F (0.5°C)
C. Nearest 0.5°F (0.25°C)
D. Nearest 5°F (2.5°C)
The temperature measuring device must be capable of reading to the nearest 1°F (0.5°C)
and have a range of at least 30°F to 120°F (0°C to 50°C).
For concrete containing aggregate with a nominal maximum size greater than 3 in. (75 mm), how
long may it take for heat to transfer from the aggregate to the mortar?
A. 5 minutes
B. 10 minutes
C. 15 minutes
D. Up to 20 minutes
For concrete with aggregate larger than 3 in., up to 20 minutes may be needed for heat
to transfer from the aggregate to the mortar to obtain a stable temperature reading.
A technician measures the temperature of concrete in a wheelbarrow. Is this acceptable under
ASTM C1064?
A. No, temperature must always be measured in the transport truck.
B. No, temperature must be measured in a standard cylindrical mold.
C. Yes, the temperature may be measured in a wheelbarrow or other suitable container.
D. Yes, but only if the wheelbarrow is metal.
ASTM C1064 permits temperature measurement in a wheelbarrow or other suitable
container, provided the sensing portion is submerged at least 3 in. into the concrete.
, What is the minimum temperature range that the thermometer must cover according to ASTM
C1064?
A. 20°F to 100°F (0°C to 38°C)
B. 30°F to 120°F (0°C to 50°C)
C. 40°F to 140°F (4°C to 60°C)
D. 50°F to 150°F (10°C to 65°C)
The thermometer must have a range of at least 30°F to 120°F (0°C to 50°C) to cover the
expected temperature range of fresh concrete.
A technician is measuring the temperature of concrete that contains 4 in. (100 mm) nominal
maximum size aggregate. After inserting the thermometer, the reading continues to rise slowly. What
should the technician do?
A. Record the first stable reading immediately.
B. Remove the thermometer and reinsert it in a different location.
C. Wait up to 20 minutes for the reading to stabilize before recording.
D. Add water to the concrete to accelerate temperature equalization.
For concrete with large aggregate (greater than 3 in.), up to 20 minutes may be required
for heat transfer from the aggregate to the mortar to achieve a stable reading.
Which of the following is NOT a requirement for the temperature measuring device used in
ASTM C1064?
A. It must read to the nearest 1°F (0.5°C).
B. It must have a range of at least 30°F to 120°F.
C. It must be calibrated within the last 24 hours.
D. The sensing portion must be submersible.
ASTM C1064 does not require calibration within 24 hours; it specifies accuracy, range,
and submersion requirements. Regular calibration is required but not on a 24-hour schedule.
The temperature of fresh concrete is measured primarily to:
A. Determine the concrete's compressive strength.
B. Calculate the yield of the batch.
C. Verify compliance with specification limits that affect setting, strength development, and
durability.
D. Determine the slump of the concrete.
Testing Technician –
Grade I 150 Advanced
Multiple-Choice Questions
for the September 21–22
Certification Examination
in Columbia, Maryland
Advanced / Hard (Mixed)
Construction professionals, QA/QC technicians, and candidates preparing for
ACI Grade I certification
150 multiple-choice questions with correct answers and detailed rationales
ASTM C1064, C172, C143, C138, C231, C173, and C31
Question
Section Topic ASTM Standard
Numbers
Temperature of Freshly Mixed Hydraulic-
1 C1064/C1064M 1–20
Cement Concrete
, Question
Section Topic ASTM Standard
Numbers
2 Sampling Freshly Mixed Concrete C172/C172M 21–40
3 Slump of Hydraulic-Cement Concrete C143/C143M 41–60
Density (Unit Weight), Yield, and Air Content
4 C138/C138M 61–80
(Gravimetric)
5 Air Content by the Pressure Method C231/C231M 81–100
6 Air Content by the Volumetric Method C173/C173M 101–120
Making and Curing Concrete Test Specimens
7 C31/C31M 121–140
in the Field
8 Integrated Field Scenarios and Calculations Multiple 141–150
What is the minimum submersion depth of the temperature sensing portion of the thermometer
when measuring the temperature of freshly mixed concrete?
A. 2 in. (50 mm)
B. 3 in. (75 mm)
C. 4 in. (100 mm)
D. 6 in. (150 mm)
ASTM C1064 requires the temperature sensing portion of the thermometer to be
submerged a minimum of 3 in. (75 mm) into the concrete to obtain a representative reading.
A field technician places a thermometer into fresh concrete and immediately records the
temperature. Why is this procedurally incorrect?
A. The thermometer must be calibrated before each use.
B. The thermometer must be inserted at a 45-degree angle.
, C. The reading must stabilize before recording, which typically takes 2 to 5 minutes.
D. The thermometer must be placed in the middle of the batch, not the wheelbarrow.
ASTM C1064 requires the technician to wait until the temperature reading stabilizes—
typically 2 to 5 minutes—before recording the temperature.
What is the required temperature reading accuracy for the thermometer used in ASTM C1064?
A. Nearest 2°F (1°C)
B. Nearest 1°F (0.5°C)
C. Nearest 0.5°F (0.25°C)
D. Nearest 5°F (2.5°C)
The temperature measuring device must be capable of reading to the nearest 1°F (0.5°C)
and have a range of at least 30°F to 120°F (0°C to 50°C).
For concrete containing aggregate with a nominal maximum size greater than 3 in. (75 mm), how
long may it take for heat to transfer from the aggregate to the mortar?
A. 5 minutes
B. 10 minutes
C. 15 minutes
D. Up to 20 minutes
For concrete with aggregate larger than 3 in., up to 20 minutes may be needed for heat
to transfer from the aggregate to the mortar to obtain a stable temperature reading.
A technician measures the temperature of concrete in a wheelbarrow. Is this acceptable under
ASTM C1064?
A. No, temperature must always be measured in the transport truck.
B. No, temperature must be measured in a standard cylindrical mold.
C. Yes, the temperature may be measured in a wheelbarrow or other suitable container.
D. Yes, but only if the wheelbarrow is metal.
ASTM C1064 permits temperature measurement in a wheelbarrow or other suitable
container, provided the sensing portion is submerged at least 3 in. into the concrete.
, What is the minimum temperature range that the thermometer must cover according to ASTM
C1064?
A. 20°F to 100°F (0°C to 38°C)
B. 30°F to 120°F (0°C to 50°C)
C. 40°F to 140°F (4°C to 60°C)
D. 50°F to 150°F (10°C to 65°C)
The thermometer must have a range of at least 30°F to 120°F (0°C to 50°C) to cover the
expected temperature range of fresh concrete.
A technician is measuring the temperature of concrete that contains 4 in. (100 mm) nominal
maximum size aggregate. After inserting the thermometer, the reading continues to rise slowly. What
should the technician do?
A. Record the first stable reading immediately.
B. Remove the thermometer and reinsert it in a different location.
C. Wait up to 20 minutes for the reading to stabilize before recording.
D. Add water to the concrete to accelerate temperature equalization.
For concrete with large aggregate (greater than 3 in.), up to 20 minutes may be required
for heat transfer from the aggregate to the mortar to achieve a stable reading.
Which of the following is NOT a requirement for the temperature measuring device used in
ASTM C1064?
A. It must read to the nearest 1°F (0.5°C).
B. It must have a range of at least 30°F to 120°F.
C. It must be calibrated within the last 24 hours.
D. The sensing portion must be submersible.
ASTM C1064 does not require calibration within 24 hours; it specifies accuracy, range,
and submersion requirements. Regular calibration is required but not on a 24-hour schedule.
The temperature of fresh concrete is measured primarily to:
A. Determine the concrete's compressive strength.
B. Calculate the yield of the batch.
C. Verify compliance with specification limits that affect setting, strength development, and
durability.
D. Determine the slump of the concrete.
