ACI Concrete Strength Testing
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1. What is the primary purpose of compressive strength testing of concrete?
A. To determine color consistency
B. To measure workability
C. To determine load-bearing capacity
D. To evaluate slump
Rationale: Compressive strength testing determines how much load concrete can
withstand before failure.
2. Standard concrete cylinders are typically cured for how long before testing for
28-day strength?
A. 7 days
B. 14 days
C. 28 days
D. 90 days
Rationale: 28 days is the standard curing period for determining design strength.
,3. What is the standard size of a concrete test cylinder?
A. 3 in × 6 in
B. 4 in × 6 in
C. 6 in × 12 in
D. 8 in × 16 in
Rationale: The most commonly used standard cylinder is 6 inches by 12 inches.
4. What ASTM standard governs compressive strength testing of concrete
cylinders?
A. ASTM C31
B. ASTM C138
C. ASTM C39
D. ASTM C94
Rationale: ASTM C39 covers compressive strength testing of cylindrical concrete
specimens.
5. Slump test measures which property of concrete?
A. Strength
B. Density
C. Workability
D. Air content
Rationale: Slump measures the consistency or workability of fresh concrete.
6. Which tool is used to measure slump?
A. Proctor mold
B. Abrams cone
C. Vicat apparatus
D. Pycnometer
, Rationale: The Abrams cone (slump cone) is used for slump testing.
7. What is the purpose of rodding during cylinder preparation?
A. Increase strength
B. Reduce curing time
C. Remove air voids
D. Add moisture
Rationale: Rodding consolidates concrete and removes trapped air.
8. How many layers are used when casting a standard cylinder?
A. 1
B. 2
C. 3
D. 4
Rationale: Cylinders are typically filled in three equal layers.
9. Each layer of a concrete cylinder is rodded how many times?
A. 10
B. 15
C. 25
D. 30
Rationale: ASTM C31 specifies 25 roddings per layer for 6×12 cylinders.
10. What is the maximum time allowed before starting slump test after
sampling?
A. 5 minutes
B. 10 minutes
Technician Exam Practice Test Questions
And Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A Instant
Download Pdf
1. What is the primary purpose of compressive strength testing of concrete?
A. To determine color consistency
B. To measure workability
C. To determine load-bearing capacity
D. To evaluate slump
Rationale: Compressive strength testing determines how much load concrete can
withstand before failure.
2. Standard concrete cylinders are typically cured for how long before testing for
28-day strength?
A. 7 days
B. 14 days
C. 28 days
D. 90 days
Rationale: 28 days is the standard curing period for determining design strength.
,3. What is the standard size of a concrete test cylinder?
A. 3 in × 6 in
B. 4 in × 6 in
C. 6 in × 12 in
D. 8 in × 16 in
Rationale: The most commonly used standard cylinder is 6 inches by 12 inches.
4. What ASTM standard governs compressive strength testing of concrete
cylinders?
A. ASTM C31
B. ASTM C138
C. ASTM C39
D. ASTM C94
Rationale: ASTM C39 covers compressive strength testing of cylindrical concrete
specimens.
5. Slump test measures which property of concrete?
A. Strength
B. Density
C. Workability
D. Air content
Rationale: Slump measures the consistency or workability of fresh concrete.
6. Which tool is used to measure slump?
A. Proctor mold
B. Abrams cone
C. Vicat apparatus
D. Pycnometer
, Rationale: The Abrams cone (slump cone) is used for slump testing.
7. What is the purpose of rodding during cylinder preparation?
A. Increase strength
B. Reduce curing time
C. Remove air voids
D. Add moisture
Rationale: Rodding consolidates concrete and removes trapped air.
8. How many layers are used when casting a standard cylinder?
A. 1
B. 2
C. 3
D. 4
Rationale: Cylinders are typically filled in three equal layers.
9. Each layer of a concrete cylinder is rodded how many times?
A. 10
B. 15
C. 25
D. 30
Rationale: ASTM C31 specifies 25 roddings per layer for 6×12 cylinders.
10. What is the maximum time allowed before starting slump test after
sampling?
A. 5 minutes
B. 10 minutes
