ACI Concrete Field Testing Technician
Grade I Certification Practice Exam 100
Questions And Correct Answers
(Verified Answers) Plus Rationales
2026 Q&A Instant Download Pdf
1. According to ASTM C172, which sampling method produces a
representative composite sample from a truck mixer?
A. Collecting one scoop from the beginning of discharge only
B. Collecting two or more portions at regularly spaced intervals during
discharge, avoiding the first and last portions
C. Collecting a single portion from the middle of the discharge
D. Collecting from the drum before discharge begins
Correct Answer: B. Collecting two or more portions at regularly spaced
intervals during discharge, avoiding the first and last portions
ASTM C172 requires composite sampling by collecting two or more portions
at regularly spaced intervals throughout the discharge. The first and last
portions are avoided because they tend to be less representative of the entire
load due to segregation and variation.
2. What is the maximum time allowed between obtaining a concrete sample
and completing the slump test when the sample is protected from
evaporation?
A. 5 minutes
B. 15 minutes
C. 30 minutes
D. 45 minutes
Correct Answer: A. 5 minutes
,ASTM C143 specifies that the slump test must be completed within 5 minutes
after obtaining the sample when the sample is protected from evaporation.
This ensures the concrete has not begun to set or lose workability.
3. How many layers is concrete placed into the slump cone during testing per
ASTM C143?
A. One
B. Two
C. Three
D. Four
Correct Answer: C. Three
ASTM C143 requires filling the slump cone in three equal layers, with each
layer rodded 25 times using a bullet-pointed tamping rod.
4. What is the required shape of the slump cone according to ASTM C143?
A. Cylinder
B. Frustum of a cone
C. Cube
D. Prism
Correct Answer: B. Frustum of a cone
ASTM C143 specifies the slump cone as a frustum of a cone with a bottom
diameter of 8 inches (200 mm), top diameter of 4 inches (100 mm), and
height of 12 inches (300 mm).
5. What is the maximum time allowed to raise the slump cone after rodding
the final layer?
A. 1 to 3 seconds
B. 3 to 7 seconds
C. 10 to 15 seconds
D. 15 to 20 seconds
Correct Answer: B. 3 to 7 seconds
ASTM C143 states the mold must be lifted vertically in 3 to 7 seconds without
lateral or torsional motion to obtain a valid slump measurement.
,6. Which ASTM standard governs air content testing by the pressure method?
A. ASTM C173
B. ASTM C231
C. ASTM C138
D. ASTM C1064
Correct Answer: B. ASTM C231
ASTM C231 covers the pressure method for determining air content of freshly
mixed concrete. ASTM C173 is the volumetric method, C138 is density/yield,
and C1064 is temperature.
7. According to ASTM C1064, what is the minimum immersion depth for a
temperature sensor in fresh concrete?
A. 1 inch (25 mm)
B. 2 inches (50 mm)
C. 3 inches (75 mm)
D. 4 inches (100 mm)
Correct Answer: C. 3 inches (75 mm)
ASTM C1064 requires the temperature sensor to be immersed at least 3
inches (75 mm) into the concrete and left in place for a minimum of 2 minutes
before reading.
8. What is the minimum time the temperature sensor must remain in the
concrete before reading per ASTM C1064?
A. 30 seconds
B. 1 minute
C. 2 minutes
D. 5 minutes
Correct Answer: C. 2 minutes
ASTM C1064 specifies that the temperature measuring device must remain in
the concrete for at least 2 minutes or until the temperature reading stabilizes,
whichever is longer.
9. Which ASTM standard covers the volumetric method for determining air
content of fresh concrete?
, A. ASTM C231
B. ASTM C173
C. ASTM C138
D. ASTM C143
Correct Answer: B. ASTM C173
ASTM C173 is the standard test method for air content of freshly mixed
concrete by the volumetric method, commonly known as the Roll-A-Meter
test.
10. What is the primary purpose of ASTM C138?
A. Determining slump of concrete
B. Determining air content by pressure
C. Determining density (unit weight), yield, and air content (gravimetric)
D. Determining temperature of concrete
Correct Answer: C. Determining density (unit weight), yield, and air content
(gravimetric)
ASTM C138 provides procedures for determining the density (unit weight) of
freshly mixed concrete and gives formulas for calculating yield, cement
content, and gravimetric air content.
11. How many lifts are required when consolidating concrete in a cylinder
mold per ASTM C31?
A. One lift
B. Two lifts
C. Three lifts
D. Four lifts
Correct Answer: C. Three lifts
ASTM C31 requires concrete to be placed in cylinder molds in three
approximately equal layers, with each layer rodded a specified number of
times based on mold diameter.
12. For a 4-inch diameter cylinder, how many rodding blows are required per
layer per ASTM C31?
A. 10
Grade I Certification Practice Exam 100
Questions And Correct Answers
(Verified Answers) Plus Rationales
2026 Q&A Instant Download Pdf
1. According to ASTM C172, which sampling method produces a
representative composite sample from a truck mixer?
A. Collecting one scoop from the beginning of discharge only
B. Collecting two or more portions at regularly spaced intervals during
discharge, avoiding the first and last portions
C. Collecting a single portion from the middle of the discharge
D. Collecting from the drum before discharge begins
Correct Answer: B. Collecting two or more portions at regularly spaced
intervals during discharge, avoiding the first and last portions
ASTM C172 requires composite sampling by collecting two or more portions
at regularly spaced intervals throughout the discharge. The first and last
portions are avoided because they tend to be less representative of the entire
load due to segregation and variation.
2. What is the maximum time allowed between obtaining a concrete sample
and completing the slump test when the sample is protected from
evaporation?
A. 5 minutes
B. 15 minutes
C. 30 minutes
D. 45 minutes
Correct Answer: A. 5 minutes
,ASTM C143 specifies that the slump test must be completed within 5 minutes
after obtaining the sample when the sample is protected from evaporation.
This ensures the concrete has not begun to set or lose workability.
3. How many layers is concrete placed into the slump cone during testing per
ASTM C143?
A. One
B. Two
C. Three
D. Four
Correct Answer: C. Three
ASTM C143 requires filling the slump cone in three equal layers, with each
layer rodded 25 times using a bullet-pointed tamping rod.
4. What is the required shape of the slump cone according to ASTM C143?
A. Cylinder
B. Frustum of a cone
C. Cube
D. Prism
Correct Answer: B. Frustum of a cone
ASTM C143 specifies the slump cone as a frustum of a cone with a bottom
diameter of 8 inches (200 mm), top diameter of 4 inches (100 mm), and
height of 12 inches (300 mm).
5. What is the maximum time allowed to raise the slump cone after rodding
the final layer?
A. 1 to 3 seconds
B. 3 to 7 seconds
C. 10 to 15 seconds
D. 15 to 20 seconds
Correct Answer: B. 3 to 7 seconds
ASTM C143 states the mold must be lifted vertically in 3 to 7 seconds without
lateral or torsional motion to obtain a valid slump measurement.
,6. Which ASTM standard governs air content testing by the pressure method?
A. ASTM C173
B. ASTM C231
C. ASTM C138
D. ASTM C1064
Correct Answer: B. ASTM C231
ASTM C231 covers the pressure method for determining air content of freshly
mixed concrete. ASTM C173 is the volumetric method, C138 is density/yield,
and C1064 is temperature.
7. According to ASTM C1064, what is the minimum immersion depth for a
temperature sensor in fresh concrete?
A. 1 inch (25 mm)
B. 2 inches (50 mm)
C. 3 inches (75 mm)
D. 4 inches (100 mm)
Correct Answer: C. 3 inches (75 mm)
ASTM C1064 requires the temperature sensor to be immersed at least 3
inches (75 mm) into the concrete and left in place for a minimum of 2 minutes
before reading.
8. What is the minimum time the temperature sensor must remain in the
concrete before reading per ASTM C1064?
A. 30 seconds
B. 1 minute
C. 2 minutes
D. 5 minutes
Correct Answer: C. 2 minutes
ASTM C1064 specifies that the temperature measuring device must remain in
the concrete for at least 2 minutes or until the temperature reading stabilizes,
whichever is longer.
9. Which ASTM standard covers the volumetric method for determining air
content of fresh concrete?
, A. ASTM C231
B. ASTM C173
C. ASTM C138
D. ASTM C143
Correct Answer: B. ASTM C173
ASTM C173 is the standard test method for air content of freshly mixed
concrete by the volumetric method, commonly known as the Roll-A-Meter
test.
10. What is the primary purpose of ASTM C138?
A. Determining slump of concrete
B. Determining air content by pressure
C. Determining density (unit weight), yield, and air content (gravimetric)
D. Determining temperature of concrete
Correct Answer: C. Determining density (unit weight), yield, and air content
(gravimetric)
ASTM C138 provides procedures for determining the density (unit weight) of
freshly mixed concrete and gives formulas for calculating yield, cement
content, and gravimetric air content.
11. How many lifts are required when consolidating concrete in a cylinder
mold per ASTM C31?
A. One lift
B. Two lifts
C. Three lifts
D. Four lifts
Correct Answer: C. Three lifts
ASTM C31 requires concrete to be placed in cylinder molds in three
approximately equal layers, with each layer rodded a specified number of
times based on mold diameter.
12. For a 4-inch diameter cylinder, how many rodding blows are required per
layer per ASTM C31?
A. 10
