ACI Concrete Field Testing Technician
Grade II Certification Practice Exam
100 Questions And Correct Answers
(Verified Answers) Plus Rationales
2026 Q&A Instant Download Pdf
1. What is the primary purpose of representative sampling of freshly mixed
concrete?
A. To obtain the largest possible sample
B. To obtain a sample that accurately represents the concrete being delivered
C. To reduce the amount of concrete tested
D. To increase the measured slump
B. To obtain a sample that accurately represents the concrete being delivered
Rationale: A representative sample is essential because test results are only
meaningful when the material tested reflects the concrete actually being
placed. Sampling must be performed at the proper point in the delivery
process without intentionally selecting unusually wet, dry, coarse, or fine
portions of the load.
2. When sampling concrete from a revolving-drum mixer, where should
portions of the composite sample generally be obtained?
A. Only from the first concrete discharged
B. Only from the last concrete discharged
C. From at least two portions taken during discharge
D. From concrete remaining inside the drum
C. From at least two portions taken during discharge
Rationale: Multiple portions taken at suitable intervals during discharge
provide a more representative composite sample than a single grab sample.
This accounts for normal variations within the load.
,3. What should be done to a composite sample before performing most
fresh-concrete tests?
A. Allow it to sit until bleeding begins
B. Protect it from contamination and remix it sufficiently
C. Add water to restore its original slump
D. Separate the coarse aggregate
B. Protect it from contamination and remix it sufficiently
Rationale: A composite sample should be protected from contamination and
evaporation. Before testing, it is generally remixed to ensure uniformity.
Adding water would change the concrete and invalidate test results.
4. Why is excessive delay between sampling and testing undesirable?
A. It increases aggregate size
B. Concrete properties can change with time
C. Cement stops hydrating immediately
D. The sample becomes chemically inert
B. Concrete properties can change with time
Rationale: Fresh concrete begins changing as soon as cement and water
interact. Slump may decrease, temperature may change, and setting may
begin. Tests should be performed promptly.
5. Which action is most likely to contaminate a concrete sample?
A. Covering the sample to protect it
B. Remixing the sample before testing
C. Allowing soil or debris to enter the sample
D. Testing the sample promptly
C. Allowing soil or debris to enter the sample
Rationale: Foreign material can alter the physical composition of the sample
and affect test results. Clean equipment and a clean, nonabsorbent sampling
surface should be used.
6. What is the principal purpose of the slump test?
A. To directly measure compressive strength
B. To determine cement content
, C. To measure consistency of freshly mixed concrete
D. To determine aggregate absorption
C. To measure consistency of freshly mixed concrete
Rationale: The slump test provides an indication of the consistency or relative
workability of freshly mixed concrete. It does not directly measure strength,
water-cement ratio, or durability.
7. What should the slump cone be placed on during the slump test?
A. An absorbent wooden surface
B. A clean, rigid, level, nonabsorbent surface
C. Loose aggregate
D. Freshly compacted soil
B. A clean, rigid, level, nonabsorbent surface
Rationale: The base must provide stable support and prevent loss of water
from the sample. An uneven, flexible, or absorbent surface can interfere with
the test.
8. How should the slump cone generally be filled?
A. In one large lift
B. In two equal lifts
C. In three specified layers
D. Only halfway
C. In three specified layers
Rationale: The slump procedure uses three layers so that the concrete can be
properly consolidated throughout the cone. Each layer receives the specified
number of rodding strokes.
9. Which ASTM standard governs the slump test?
A. ASTM C31
B. ASTM C143
C. ASTM C39
D. ASTM C231
B. ASTM C143
Rationale: ASTM C143 outlines the procedure for slump testing of hydraulic-
cement concrete.
Grade II Certification Practice Exam
100 Questions And Correct Answers
(Verified Answers) Plus Rationales
2026 Q&A Instant Download Pdf
1. What is the primary purpose of representative sampling of freshly mixed
concrete?
A. To obtain the largest possible sample
B. To obtain a sample that accurately represents the concrete being delivered
C. To reduce the amount of concrete tested
D. To increase the measured slump
B. To obtain a sample that accurately represents the concrete being delivered
Rationale: A representative sample is essential because test results are only
meaningful when the material tested reflects the concrete actually being
placed. Sampling must be performed at the proper point in the delivery
process without intentionally selecting unusually wet, dry, coarse, or fine
portions of the load.
2. When sampling concrete from a revolving-drum mixer, where should
portions of the composite sample generally be obtained?
A. Only from the first concrete discharged
B. Only from the last concrete discharged
C. From at least two portions taken during discharge
D. From concrete remaining inside the drum
C. From at least two portions taken during discharge
Rationale: Multiple portions taken at suitable intervals during discharge
provide a more representative composite sample than a single grab sample.
This accounts for normal variations within the load.
,3. What should be done to a composite sample before performing most
fresh-concrete tests?
A. Allow it to sit until bleeding begins
B. Protect it from contamination and remix it sufficiently
C. Add water to restore its original slump
D. Separate the coarse aggregate
B. Protect it from contamination and remix it sufficiently
Rationale: A composite sample should be protected from contamination and
evaporation. Before testing, it is generally remixed to ensure uniformity.
Adding water would change the concrete and invalidate test results.
4. Why is excessive delay between sampling and testing undesirable?
A. It increases aggregate size
B. Concrete properties can change with time
C. Cement stops hydrating immediately
D. The sample becomes chemically inert
B. Concrete properties can change with time
Rationale: Fresh concrete begins changing as soon as cement and water
interact. Slump may decrease, temperature may change, and setting may
begin. Tests should be performed promptly.
5. Which action is most likely to contaminate a concrete sample?
A. Covering the sample to protect it
B. Remixing the sample before testing
C. Allowing soil or debris to enter the sample
D. Testing the sample promptly
C. Allowing soil or debris to enter the sample
Rationale: Foreign material can alter the physical composition of the sample
and affect test results. Clean equipment and a clean, nonabsorbent sampling
surface should be used.
6. What is the principal purpose of the slump test?
A. To directly measure compressive strength
B. To determine cement content
, C. To measure consistency of freshly mixed concrete
D. To determine aggregate absorption
C. To measure consistency of freshly mixed concrete
Rationale: The slump test provides an indication of the consistency or relative
workability of freshly mixed concrete. It does not directly measure strength,
water-cement ratio, or durability.
7. What should the slump cone be placed on during the slump test?
A. An absorbent wooden surface
B. A clean, rigid, level, nonabsorbent surface
C. Loose aggregate
D. Freshly compacted soil
B. A clean, rigid, level, nonabsorbent surface
Rationale: The base must provide stable support and prevent loss of water
from the sample. An uneven, flexible, or absorbent surface can interfere with
the test.
8. How should the slump cone generally be filled?
A. In one large lift
B. In two equal lifts
C. In three specified layers
D. Only halfway
C. In three specified layers
Rationale: The slump procedure uses three layers so that the concrete can be
properly consolidated throughout the cone. Each layer receives the specified
number of rodding strokes.
9. Which ASTM standard governs the slump test?
A. ASTM C31
B. ASTM C143
C. ASTM C39
D. ASTM C231
B. ASTM C143
Rationale: ASTM C143 outlines the procedure for slump testing of hydraulic-
cement concrete.
