Nevada C-5 Concrete Contractor Exam
Practice Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. Which of the following is the most important factor in determining the
workability of concrete?
A. Aggregate size
B. Water-cement ratio
C. Type of cement
D. Ambient temperature
B. Water-cement ratio
The water-cement ratio controls the workability, strength, and durability
of concrete. Too much water reduces strength, while too little affects
placement.
2. What is the recommended maximum slump for structural concrete
that is placed using forms and compacted by vibration?
A. 8 inches
B. 6 inches
C. 4 inches
D. 2 inches
C. 4 inches
A slump of 4 inches is considered ideal for vibrated structural concrete,
ensuring workability without excessive bleeding.
3. During curing, which condition is most critical for concrete strength
development?
A. High wind
, B. Moisture retention
C. Direct sunlight
D. Rapid finishing
B. Moisture retention
Concrete gains strength through hydration, which requires adequate
moisture; drying too quickly reduces final strength.
4. Which type of cement is commonly used for mass concrete structures
to reduce heat of hydration?
A. Type I
B. Type II
C. Type III
D. Type V
B. Type II
Type II cement is designed for moderate heat of hydration and is
commonly used in large pours to minimize thermal cracking.
5. What is the primary purpose of reinforcing steel in concrete?
A. Increase fire resistance
B. Increase tensile strength
C. Improve workability
D. Reduce weight
B. Increase tensile strength
Concrete is strong in compression but weak in tension; reinforcing steel
provides the necessary tensile strength.
6. Which method is best for checking the uniformity of concrete mix on-
site?
A. Slump test
B. Flow test
C. Compressive strength test
D. Air content test
, A. Slump test
The slump test is a quick and effective field method to assess concrete
consistency and uniformity.
7. What is the minimum concrete cover for steel reinforcement in
exterior concrete exposed to weather?
A. 1 inch
B. 2 inches
C. 3 inches
D. 4 inches
A. 1 inch
Exterior reinforced concrete requires at least 1 inch cover to protect steel
from corrosion.
8. In hot weather, which action helps prevent premature concrete
setting?
A. Use Type III cement
B. Increase water content significantly
C. Use chilled mixing water
D. Reduce aggregate size
C. Use chilled mixing water
Lowering the temperature of concrete components slows hydration,
reducing the risk of premature setting in hot weather.
9. What is the typical compressive strength of structural concrete after
28 days?
A. 1,000–2,000 psi
B. 2,500–3,500 psi
C. 4,000–5,000 psi
D. 6,000–7,000 psi
C. 4,000–5,000 psi
Most structural concrete is designed to achieve 4,000–5,000 psi at 28 days,
ensuring adequate load-bearing capacity.
Practice Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. Which of the following is the most important factor in determining the
workability of concrete?
A. Aggregate size
B. Water-cement ratio
C. Type of cement
D. Ambient temperature
B. Water-cement ratio
The water-cement ratio controls the workability, strength, and durability
of concrete. Too much water reduces strength, while too little affects
placement.
2. What is the recommended maximum slump for structural concrete
that is placed using forms and compacted by vibration?
A. 8 inches
B. 6 inches
C. 4 inches
D. 2 inches
C. 4 inches
A slump of 4 inches is considered ideal for vibrated structural concrete,
ensuring workability without excessive bleeding.
3. During curing, which condition is most critical for concrete strength
development?
A. High wind
, B. Moisture retention
C. Direct sunlight
D. Rapid finishing
B. Moisture retention
Concrete gains strength through hydration, which requires adequate
moisture; drying too quickly reduces final strength.
4. Which type of cement is commonly used for mass concrete structures
to reduce heat of hydration?
A. Type I
B. Type II
C. Type III
D. Type V
B. Type II
Type II cement is designed for moderate heat of hydration and is
commonly used in large pours to minimize thermal cracking.
5. What is the primary purpose of reinforcing steel in concrete?
A. Increase fire resistance
B. Increase tensile strength
C. Improve workability
D. Reduce weight
B. Increase tensile strength
Concrete is strong in compression but weak in tension; reinforcing steel
provides the necessary tensile strength.
6. Which method is best for checking the uniformity of concrete mix on-
site?
A. Slump test
B. Flow test
C. Compressive strength test
D. Air content test
, A. Slump test
The slump test is a quick and effective field method to assess concrete
consistency and uniformity.
7. What is the minimum concrete cover for steel reinforcement in
exterior concrete exposed to weather?
A. 1 inch
B. 2 inches
C. 3 inches
D. 4 inches
A. 1 inch
Exterior reinforced concrete requires at least 1 inch cover to protect steel
from corrosion.
8. In hot weather, which action helps prevent premature concrete
setting?
A. Use Type III cement
B. Increase water content significantly
C. Use chilled mixing water
D. Reduce aggregate size
C. Use chilled mixing water
Lowering the temperature of concrete components slows hydration,
reducing the risk of premature setting in hot weather.
9. What is the typical compressive strength of structural concrete after
28 days?
A. 1,000–2,000 psi
B. 2,500–3,500 psi
C. 4,000–5,000 psi
D. 6,000–7,000 psi
C. 4,000–5,000 psi
Most structural concrete is designed to achieve 4,000–5,000 psi at 28 days,
ensuring adequate load-bearing capacity.
