ACI CONCRETE FIELD TESTING
TECHNICIAN GRADE I: (LATEST 2026/2027
UPDATE) QUESTIONS WITH ANSWERS |
GRADE A | 100% CORRECT
ACI CONCRETE FIELD TESTING TECHNICIAN
GRADE I
1. The sensor of the temperature measuring device shall be
submerged a minimum of how many inches [mm] into freshly mixed
concrete?
A. 1 in. [25 mm]
B. 2 in. [50 mm]
C. 3 in. [75 mm]
D. 4 in. [100 mm]
Answer: C. 3 in. [75 mm]
Rationale: The sensor must be submerged sufficiently to ensure it accurately
measures the internal temperature of the concrete rather than the surface
temperature, which can vary due to environmental conditions. A depth of 3 inches
ensures proper immersion in the mass of concrete.
2. The temperature measuring device shall have a capacity of
measuring the temperature of freshly mixed concrete to ± how
many degrees Fahrenheit [°C], throughout what range?
A. ±1°F [0.5°C], 30°F to 120°F [0°C to 50°C]
B. ±2°F [1°C], 32°F to 122°F [0°C to 50°C]
C. ±1°F [0.5°C], 40°F to 140°F [4°C to 60°C]
D. ±5°F [2.5°C], 30°F to 120°F [0°C to 50°C]
Answer: A. ±1°F [0.5°C], 30°F to 120°F [0°C to 50°C]
,Rationale: Accuracy of ±1°F [0.5°C] is required to reliably track concrete
temperature changes. The range 30°F to 120°F [0°C to 50°C] covers the temperatures
commonly encountered in freshly mixed concrete under typical field conditions.
3. How often should the temperature measuring device be
calibrated, or when should it be calibrated?
A. Every 6 months or whenever accuracy is in question
B. Annually or whenever accuracy is in question
C. Every 2 years only
D. Only when first purchased
Answer: B. Annually or whenever accuracy is in question
Rationale: Regular calibration ensures the device maintains accuracy and reliability.
Calibration whenever accuracy is uncertain prevents errors in temperature
measurement, which is critical for concrete performance and curing.
4. True or False: The temperature of concrete may be measured in a
wheelbarrow.
A. True
B. False
Answer: A. True
Rationale: Concrete can be sampled and tested for temperature in a wheelbarrow
because it is convenient and allows the sensor to be properly immersed. Care should
be taken to avoid contamination or heat loss during measurement.
5. True or False: The temperature of concrete may be measured in a
wall form.
A. True
B. False
Answer: A. True
Rationale: Measuring in a wall form is acceptable if the sensor is properly positioned
in the mass of concrete. This ensures the temperature reading represents the bulk
concrete rather than only the exposed surface.
,6. True or False: A composite sample of concrete is required even if
the only purpose for obtaining the sample is to determine
temperature.
A. True
B. False
Answer: B. False
Rationale: Composite samples are only required when multiple tests (like slump, air
content, or strength) are being performed. Temperature measurement requires only a
single representative portion, so a composite sample is unnecessary.
7. What must be done to the sample container prior to sampling
concrete?
A. Leave it dry
B. Line it with plastic
C. Dampen it with water
D. Fill it with sand
Answer: C. Dampen it with water
Rationale: Damping the container prevents premature hydration of the concrete at
the container surface. This ensures the sample accurately represents the fresh
concrete’s temperature and properties.
8. After the temperature measuring device is submerged in freshly
mixed concrete, what must be done to the surrounding concrete?
A. Leave it undisturbed
B. Gently consolidate around the sensor
C. Mix the concrete around it
D. Cover it immediately with plastic
Answer: B. Gently consolidate around the sensor
Rationale: Consolidating the concrete around the sensor eliminates air pockets and
ensures full contact with the concrete mass, giving an accurate temperature reading.
Improper placement can result in misleading readings.
, 9. When measuring the temperature of freshly mixed concrete, at
what location in a large batch should the sample ideally be taken?
A. Near the surface of the concrete
B. Near the edges of the formwork
C. From the middle of the batch or mass
D. Randomly from any location
Answer: C. From the middle of the batch or mass
Rationale: The middle of the concrete mass represents the average temperature of
the batch. Measuring near the surface or edges may give readings affected by
environmental conditions like sun or wind.
10. The slump test is performed to determine which property of
freshly mixed concrete?
A. Air content
B. Workability or consistency
C. Temperature
D. Compressive strength
Answer: B. Workability or consistency
Rationale: The slump test evaluates how easily concrete flows, which is essential for
proper placement and consolidation. A higher slump indicates more workable
concrete, while a lower slump indicates stiffer concrete.
11. Which type of slump is observed when the concrete subsides
evenly, with no shear or collapse?
A. True slump
B. Shear slump
C. Collapse slump
D. False slump
Answer: A. True slump
Rationale: A true slump occurs when the concrete settles uniformly without breaking
apart, indicating good consistency. Shear or collapse slumps indicate instability or
overly wet concrete.
TECHNICIAN GRADE I: (LATEST 2026/2027
UPDATE) QUESTIONS WITH ANSWERS |
GRADE A | 100% CORRECT
ACI CONCRETE FIELD TESTING TECHNICIAN
GRADE I
1. The sensor of the temperature measuring device shall be
submerged a minimum of how many inches [mm] into freshly mixed
concrete?
A. 1 in. [25 mm]
B. 2 in. [50 mm]
C. 3 in. [75 mm]
D. 4 in. [100 mm]
Answer: C. 3 in. [75 mm]
Rationale: The sensor must be submerged sufficiently to ensure it accurately
measures the internal temperature of the concrete rather than the surface
temperature, which can vary due to environmental conditions. A depth of 3 inches
ensures proper immersion in the mass of concrete.
2. The temperature measuring device shall have a capacity of
measuring the temperature of freshly mixed concrete to ± how
many degrees Fahrenheit [°C], throughout what range?
A. ±1°F [0.5°C], 30°F to 120°F [0°C to 50°C]
B. ±2°F [1°C], 32°F to 122°F [0°C to 50°C]
C. ±1°F [0.5°C], 40°F to 140°F [4°C to 60°C]
D. ±5°F [2.5°C], 30°F to 120°F [0°C to 50°C]
Answer: A. ±1°F [0.5°C], 30°F to 120°F [0°C to 50°C]
,Rationale: Accuracy of ±1°F [0.5°C] is required to reliably track concrete
temperature changes. The range 30°F to 120°F [0°C to 50°C] covers the temperatures
commonly encountered in freshly mixed concrete under typical field conditions.
3. How often should the temperature measuring device be
calibrated, or when should it be calibrated?
A. Every 6 months or whenever accuracy is in question
B. Annually or whenever accuracy is in question
C. Every 2 years only
D. Only when first purchased
Answer: B. Annually or whenever accuracy is in question
Rationale: Regular calibration ensures the device maintains accuracy and reliability.
Calibration whenever accuracy is uncertain prevents errors in temperature
measurement, which is critical for concrete performance and curing.
4. True or False: The temperature of concrete may be measured in a
wheelbarrow.
A. True
B. False
Answer: A. True
Rationale: Concrete can be sampled and tested for temperature in a wheelbarrow
because it is convenient and allows the sensor to be properly immersed. Care should
be taken to avoid contamination or heat loss during measurement.
5. True or False: The temperature of concrete may be measured in a
wall form.
A. True
B. False
Answer: A. True
Rationale: Measuring in a wall form is acceptable if the sensor is properly positioned
in the mass of concrete. This ensures the temperature reading represents the bulk
concrete rather than only the exposed surface.
,6. True or False: A composite sample of concrete is required even if
the only purpose for obtaining the sample is to determine
temperature.
A. True
B. False
Answer: B. False
Rationale: Composite samples are only required when multiple tests (like slump, air
content, or strength) are being performed. Temperature measurement requires only a
single representative portion, so a composite sample is unnecessary.
7. What must be done to the sample container prior to sampling
concrete?
A. Leave it dry
B. Line it with plastic
C. Dampen it with water
D. Fill it with sand
Answer: C. Dampen it with water
Rationale: Damping the container prevents premature hydration of the concrete at
the container surface. This ensures the sample accurately represents the fresh
concrete’s temperature and properties.
8. After the temperature measuring device is submerged in freshly
mixed concrete, what must be done to the surrounding concrete?
A. Leave it undisturbed
B. Gently consolidate around the sensor
C. Mix the concrete around it
D. Cover it immediately with plastic
Answer: B. Gently consolidate around the sensor
Rationale: Consolidating the concrete around the sensor eliminates air pockets and
ensures full contact with the concrete mass, giving an accurate temperature reading.
Improper placement can result in misleading readings.
, 9. When measuring the temperature of freshly mixed concrete, at
what location in a large batch should the sample ideally be taken?
A. Near the surface of the concrete
B. Near the edges of the formwork
C. From the middle of the batch or mass
D. Randomly from any location
Answer: C. From the middle of the batch or mass
Rationale: The middle of the concrete mass represents the average temperature of
the batch. Measuring near the surface or edges may give readings affected by
environmental conditions like sun or wind.
10. The slump test is performed to determine which property of
freshly mixed concrete?
A. Air content
B. Workability or consistency
C. Temperature
D. Compressive strength
Answer: B. Workability or consistency
Rationale: The slump test evaluates how easily concrete flows, which is essential for
proper placement and consolidation. A higher slump indicates more workable
concrete, while a lower slump indicates stiffer concrete.
11. Which type of slump is observed when the concrete subsides
evenly, with no shear or collapse?
A. True slump
B. Shear slump
C. Collapse slump
D. False slump
Answer: A. True slump
Rationale: A true slump occurs when the concrete settles uniformly without breaking
apart, indicating good consistency. Shear or collapse slumps indicate instability or
overly wet concrete.
