Nevada C-5 Concrete Contractor
Exam Practice Test Questions And
Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A | Instant
Download Pdf
1. Which of the following is the primary function of Portland cement in
concrete?
a) Reduce water demand
b) Provide strength and binding
c) Increase workability
d) Act as a filler
b) Provide strength and binding
Portland cement reacts with water to form a hardened matrix that
binds aggregates together, giving concrete its strength.
2. What is the typical water-cement ratio range for normal concrete?
a) 0.10–0.20
b) 0.30–0.60
c) 0.70–0.90
d) 1.00–1.20
b) 0.30–0.60
Water-cement ratio controls strength and durability. Lower ratios
increase strength but reduce workability.
3. Which aggregate size is usually preferred for reinforced concrete slabs?
a) 3/8 inch
b) 1/2 inch
c) 3/4 inch
d) 2 inches
c) 3/4 inch
Maximum aggregate size should not exceed one-third of slab
thickness; 3/4 inch is common for slabs.
,4. What is the main purpose of air-entraining agents in concrete?
a) Increase compressive strength
b) Improve workability
c) Enhance resistance to freeze-thaw cycles
d) Reduce setting time
c) Enhance resistance to freeze-thaw cycles
Air-entraining agents create microscopic air bubbles that relieve
internal pressure during freezing and thawing.
5. Which type of cement is commonly used for high-early-strength
concrete?
a) Type I
b) Type II
c) Type III
d) Type IV
c) Type III
Type III cement is finely ground to accelerate hydration and achieve
high early strength.
6. What slump value indicates very stiff concrete?
a) 1–2 inches
b) 3–4 inches
c) 5–6 inches
d) 7–8 inches
a) 1–2 inches
Lower slump values indicate lower workability and stiffer concrete.
7. What is the minimum curing period recommended for concrete exposed
to normal conditions?
a) 1 day
b) 3 days
c) 7 days
d) 28 days
c) 7 days
Curing maintains moisture and temperature to ensure adequate
strength development; 7 days is minimum, though 28 days is standard
for full strength.
8. Which test measures the compressive strength of concrete?
a) Slump test
b) Cylinder test
, c) Air content test
d) Flexural test
b) Cylinder test
Concrete cylinders are cast, cured, and tested under compression to
determine strength.
9. What is the recommended maximum slump for concrete placed in
heavily reinforced beams?
a) 1 inch
b) 2 inches
c) 4 inches
d) 6 inches
c) 4 inches
Moderate slump improves flow around reinforcement without
excessive segregation.
10. Which of the following admixtures is used to delay the setting
time of concrete in hot weather?
a) Accelerator
b) Retarder
c) Plasticizer
d) Air-entrainer
b) Retarder
Retarders slow the hydration process, allowing more time for
placement and finishing in high temperatures.
11. What is the primary purpose of reinforcement in concrete?
a) Reduce shrinkage
b) Provide tensile strength
c) Improve workability
d) Increase water retention
b) Provide tensile strength
Concrete is strong in compression but weak in tension; reinforcement
resists tensile forces.
12. What is the typical thickness range for a residential concrete slab
on grade?
a) 2–3 inches
b) 3–4 inches
c) 4–6 inches
d) 6–8 inches
Exam Practice Test Questions And
Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A | Instant
Download Pdf
1. Which of the following is the primary function of Portland cement in
concrete?
a) Reduce water demand
b) Provide strength and binding
c) Increase workability
d) Act as a filler
b) Provide strength and binding
Portland cement reacts with water to form a hardened matrix that
binds aggregates together, giving concrete its strength.
2. What is the typical water-cement ratio range for normal concrete?
a) 0.10–0.20
b) 0.30–0.60
c) 0.70–0.90
d) 1.00–1.20
b) 0.30–0.60
Water-cement ratio controls strength and durability. Lower ratios
increase strength but reduce workability.
3. Which aggregate size is usually preferred for reinforced concrete slabs?
a) 3/8 inch
b) 1/2 inch
c) 3/4 inch
d) 2 inches
c) 3/4 inch
Maximum aggregate size should not exceed one-third of slab
thickness; 3/4 inch is common for slabs.
,4. What is the main purpose of air-entraining agents in concrete?
a) Increase compressive strength
b) Improve workability
c) Enhance resistance to freeze-thaw cycles
d) Reduce setting time
c) Enhance resistance to freeze-thaw cycles
Air-entraining agents create microscopic air bubbles that relieve
internal pressure during freezing and thawing.
5. Which type of cement is commonly used for high-early-strength
concrete?
a) Type I
b) Type II
c) Type III
d) Type IV
c) Type III
Type III cement is finely ground to accelerate hydration and achieve
high early strength.
6. What slump value indicates very stiff concrete?
a) 1–2 inches
b) 3–4 inches
c) 5–6 inches
d) 7–8 inches
a) 1–2 inches
Lower slump values indicate lower workability and stiffer concrete.
7. What is the minimum curing period recommended for concrete exposed
to normal conditions?
a) 1 day
b) 3 days
c) 7 days
d) 28 days
c) 7 days
Curing maintains moisture and temperature to ensure adequate
strength development; 7 days is minimum, though 28 days is standard
for full strength.
8. Which test measures the compressive strength of concrete?
a) Slump test
b) Cylinder test
, c) Air content test
d) Flexural test
b) Cylinder test
Concrete cylinders are cast, cured, and tested under compression to
determine strength.
9. What is the recommended maximum slump for concrete placed in
heavily reinforced beams?
a) 1 inch
b) 2 inches
c) 4 inches
d) 6 inches
c) 4 inches
Moderate slump improves flow around reinforcement without
excessive segregation.
10. Which of the following admixtures is used to delay the setting
time of concrete in hot weather?
a) Accelerator
b) Retarder
c) Plasticizer
d) Air-entrainer
b) Retarder
Retarders slow the hydration process, allowing more time for
placement and finishing in high temperatures.
11. What is the primary purpose of reinforcement in concrete?
a) Reduce shrinkage
b) Provide tensile strength
c) Improve workability
d) Increase water retention
b) Provide tensile strength
Concrete is strong in compression but weak in tension; reinforcement
resists tensile forces.
12. What is the typical thickness range for a residential concrete slab
on grade?
a) 2–3 inches
b) 3–4 inches
c) 4–6 inches
d) 6–8 inches
