Arizona CR-9 Concrete Contractor Exam
Practice Questions And Correct Answers
(Verified Answers) Plus Rationale 2026
Q&A| Instant Download Pdf
1. Which AASHTO specification is most commonly referenced for
concrete mix design in Arizona CR-9 exams?
A. ASTM C94
B. AASHTO M157
C. ACI 301
D. ASTM C150
The AASHTO M157 standard is widely used as the basis for concrete
mix design procedures in many DOT specifications, including Arizona.
2. What is the primary purpose of slump testing concrete on a jobsite?
A. To measure compressive strength potential
B. To determine cement content
C. To assess workability of fresh concrete
D. To check aggregate gradation
Slump testing provides a field measure of concrete workability and
consistency, not strength or material proportions.
3. In concrete terminology, “bleeding” refers to:
A. Loss of cement paste to evaporation
B. Cracking due to shrinkage
, C. Water rising to the surface after placement
D. Corrosion of reinforcing steel
Bleeding is the separation of water that rises to the surface of freshly
placed concrete as heavier particles settle.
4. What is the minimum compressive strength required for structural
concrete in most residential applications?
A. 2,000 psi
B. 3,000 psi
C. 4,500 psi
D. 5,000 psi
A minimum of 3,000 psi at 28 days is a typical requirement for
general residential structural concrete.
5. Which of the following admixtures reduces the water requirement
while increasing the workability of a concrete mix?
A. Retarder
B. Accelerator
C. Air-entraining agent
D. Superplasticizer
Superplasticizers are high-range water reducers that significantly
improve workability without adding water.
6. What is the primary concern addressed by air-entraining admixtures
in concrete?
A. Higher compressive strength
B. Improved freeze-thaw durability
C. Faster set times
D. Reduced bleeding
Air entrainment introduces microscopic air bubbles that improve
resistance to freeze–thaw cycles in environments like Arizona’s high
altitude areas.
, 7. Which test method is used to determine the flexural strength of
concrete?
A. Cylinder compression test
B. Beam test
C. Slump test
D. Sieve analysis
The beam flexural test measures the ability of concrete to resist
bending stresses.
8. What is the correct water-cement ratio range for achieving
high-strength concrete?
A. 0.60–0.70
B. 0.50–0.60
C. 0.30–0.45
D. 0.70–0.80
Lower water-cement ratios in the range of 0.30–0.45 produce
stronger, denser concrete when properly consolidated.
9. Which factor has the greatest influence on the strength of hardened
concrete?
A. Aggregate type
B. Water-cement ratio
C. Mixing time
D. Ambient temperature
Water-cement ratio is the controlling factor for strength development
in concrete.
10. Concrete curing is essential to:
A. Increase slump
B. Lower unit weight
C. Promote hydration and strength gain
D. Reduce aggregate segregation
Practice Questions And Correct Answers
(Verified Answers) Plus Rationale 2026
Q&A| Instant Download Pdf
1. Which AASHTO specification is most commonly referenced for
concrete mix design in Arizona CR-9 exams?
A. ASTM C94
B. AASHTO M157
C. ACI 301
D. ASTM C150
The AASHTO M157 standard is widely used as the basis for concrete
mix design procedures in many DOT specifications, including Arizona.
2. What is the primary purpose of slump testing concrete on a jobsite?
A. To measure compressive strength potential
B. To determine cement content
C. To assess workability of fresh concrete
D. To check aggregate gradation
Slump testing provides a field measure of concrete workability and
consistency, not strength or material proportions.
3. In concrete terminology, “bleeding” refers to:
A. Loss of cement paste to evaporation
B. Cracking due to shrinkage
, C. Water rising to the surface after placement
D. Corrosion of reinforcing steel
Bleeding is the separation of water that rises to the surface of freshly
placed concrete as heavier particles settle.
4. What is the minimum compressive strength required for structural
concrete in most residential applications?
A. 2,000 psi
B. 3,000 psi
C. 4,500 psi
D. 5,000 psi
A minimum of 3,000 psi at 28 days is a typical requirement for
general residential structural concrete.
5. Which of the following admixtures reduces the water requirement
while increasing the workability of a concrete mix?
A. Retarder
B. Accelerator
C. Air-entraining agent
D. Superplasticizer
Superplasticizers are high-range water reducers that significantly
improve workability without adding water.
6. What is the primary concern addressed by air-entraining admixtures
in concrete?
A. Higher compressive strength
B. Improved freeze-thaw durability
C. Faster set times
D. Reduced bleeding
Air entrainment introduces microscopic air bubbles that improve
resistance to freeze–thaw cycles in environments like Arizona’s high
altitude areas.
, 7. Which test method is used to determine the flexural strength of
concrete?
A. Cylinder compression test
B. Beam test
C. Slump test
D. Sieve analysis
The beam flexural test measures the ability of concrete to resist
bending stresses.
8. What is the correct water-cement ratio range for achieving
high-strength concrete?
A. 0.60–0.70
B. 0.50–0.60
C. 0.30–0.45
D. 0.70–0.80
Lower water-cement ratios in the range of 0.30–0.45 produce
stronger, denser concrete when properly consolidated.
9. Which factor has the greatest influence on the strength of hardened
concrete?
A. Aggregate type
B. Water-cement ratio
C. Mixing time
D. Ambient temperature
Water-cement ratio is the controlling factor for strength development
in concrete.
10. Concrete curing is essential to:
A. Increase slump
B. Lower unit weight
C. Promote hydration and strength gain
D. Reduce aggregate segregation
