NEVADA C-5 CONCRETE CONTRACTOR EXAM BANK
ACTUAL ACCURATE CURRENTLY TESTING EXAM
QUESTIONS AND ANSWERS EXPERT VERIFIED FOR
GUARANTEED PASS | LATEST UPDATE
Q1.
Before placing concrete, what should be verified about the subgrade?
A. It is slightly wet and properly compacted
B. It is rough and uneven to increase bonding
C. It contains free-standing water
D. It is covered with vapor barrier only
✔ Correct: A
Rationale: A firm, moist (not saturated) subgrade prevents absorption of mix
water and supports uniform slab thickness; uneven or muddy bases cause
settlement cracks.
Q2.
Which material is commonly used to prevent bonding between a new slab and an
existing one?
A. Epoxy resin
B. Grout
C. Plastic sheeting or bond-breaker compound
D. Rebar dowels
✔ Correct: C
Rationale: Bond breakers (e.g., plastic sheeting, curing compounds, or specialized
liquids) prevent adhesion, allowing independent movement of adjacent concrete
placements.
Q3.
What is the minimum compressive strength requirement for most Nevada
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,residential slab-on-grade concrete?
A. 2,000 psi
B. 2,500 psi
C. 3,500 psi
D. 5,000 psi
✔ Correct: B
Rationale: Nevada residential code typically requires minimum 2,500 psi for slabs.
Higher strengths may be needed for driveways or heavy loads.
Q4.
When placing concrete in hot weather (above 90°F), which practice is most
important?
A. Use hot mixing water to accelerate setting
B. Increase slump to 8 inches
C. Use set-retarding admixtures and cool aggregates
D. Place only after sunset
✔ Correct: C
Rationale: Retarders and cooling aggregates/water control rapid setting and
thermal cracking. High slump weakens concrete; hot water worsens problems.
Q5.
What is the maximum allowable slump for a typical Nevada DOT bridge
substructure concrete?
A. 1 inch
B. 3 inches
C. 5 inches
D. No limit
✔ Correct: B
Rationale: NDOT specifications often limit slump to 3 inches (±1 inch) for bridge
substructures to ensure strength and reduce segregation.
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,Q6.
The minimum concrete cover over #4 rebar in a residential foundation wall
exposed to earth is:
A. ½ inch
B. 1 inch
C. 2 inches
D. 3 inches
✔ Correct: D
Rationale: ACI 318 requires 3 inches cover for cast-in-place concrete in contact
with earth, increased to 4 inches for severe exposure.
Q7.
Which test measures the air content of fresh concrete using a pressure method?
A. Slump test
B. Unit weight test
C. Type B pressure meter
D. Penetration resistance
✔ Correct: C
Rationale: The Type B pressure meter (ASTM C231) is standard for determining
air entrainment in normal-weight concrete.
Q8.
What is the primary purpose of a keyway in a concrete slab joint?
A. Allow vertical movement
B. Transfer shear loads while permitting horizontal movement
C. Prevent cracking entirely
D. Act as a vapor barrier
✔ Correct: B
Rationale: Keyways (grooves) in construction joints transfer shear forces across
the joint while allowing some horizontal movement.
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, Q9.
Nevada’s soil conditions often include expansive clay. What foundation
reinforcement is most effective?
A. Wire mesh only
B. Increased vapor barrier
C. Post-tensioned tendons or additional rebar
D. Lightweight aggregate
✔ Correct: C
Rationale: Post-tensioning or increased steel reinforcement resists tensile forces
from expansive soil movement. Standard mesh alone is insufficient.
Q10.
The maximum time allowed between adding mixing water and completing
concrete placement (Nevada hot weather) is typically:
A. 30 minutes
B. 90 minutes
C. 3 hours
D. 6 hours
✔ Correct: B
Rationale: ACI 301 limits transit/placement time to 90 minutes (or sooner in
heat). Extended time reduces strength and workability.
Q11.
What tool is used to create a broom finish on a concrete driveway?
A. Bull float
B. Broom with stiff bristles
C. Power trowel
D. Groover
✔ Correct: B
Rationale: A stiff-bristle broom dragged across fresh concrete creates a slip-
resistant texture. Float and trowel produce smooth surfaces.
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ACTUAL ACCURATE CURRENTLY TESTING EXAM
QUESTIONS AND ANSWERS EXPERT VERIFIED FOR
GUARANTEED PASS | LATEST UPDATE
Q1.
Before placing concrete, what should be verified about the subgrade?
A. It is slightly wet and properly compacted
B. It is rough and uneven to increase bonding
C. It contains free-standing water
D. It is covered with vapor barrier only
✔ Correct: A
Rationale: A firm, moist (not saturated) subgrade prevents absorption of mix
water and supports uniform slab thickness; uneven or muddy bases cause
settlement cracks.
Q2.
Which material is commonly used to prevent bonding between a new slab and an
existing one?
A. Epoxy resin
B. Grout
C. Plastic sheeting or bond-breaker compound
D. Rebar dowels
✔ Correct: C
Rationale: Bond breakers (e.g., plastic sheeting, curing compounds, or specialized
liquids) prevent adhesion, allowing independent movement of adjacent concrete
placements.
Q3.
What is the minimum compressive strength requirement for most Nevada
1|Page
,residential slab-on-grade concrete?
A. 2,000 psi
B. 2,500 psi
C. 3,500 psi
D. 5,000 psi
✔ Correct: B
Rationale: Nevada residential code typically requires minimum 2,500 psi for slabs.
Higher strengths may be needed for driveways or heavy loads.
Q4.
When placing concrete in hot weather (above 90°F), which practice is most
important?
A. Use hot mixing water to accelerate setting
B. Increase slump to 8 inches
C. Use set-retarding admixtures and cool aggregates
D. Place only after sunset
✔ Correct: C
Rationale: Retarders and cooling aggregates/water control rapid setting and
thermal cracking. High slump weakens concrete; hot water worsens problems.
Q5.
What is the maximum allowable slump for a typical Nevada DOT bridge
substructure concrete?
A. 1 inch
B. 3 inches
C. 5 inches
D. No limit
✔ Correct: B
Rationale: NDOT specifications often limit slump to 3 inches (±1 inch) for bridge
substructures to ensure strength and reduce segregation.
2|Page
,Q6.
The minimum concrete cover over #4 rebar in a residential foundation wall
exposed to earth is:
A. ½ inch
B. 1 inch
C. 2 inches
D. 3 inches
✔ Correct: D
Rationale: ACI 318 requires 3 inches cover for cast-in-place concrete in contact
with earth, increased to 4 inches for severe exposure.
Q7.
Which test measures the air content of fresh concrete using a pressure method?
A. Slump test
B. Unit weight test
C. Type B pressure meter
D. Penetration resistance
✔ Correct: C
Rationale: The Type B pressure meter (ASTM C231) is standard for determining
air entrainment in normal-weight concrete.
Q8.
What is the primary purpose of a keyway in a concrete slab joint?
A. Allow vertical movement
B. Transfer shear loads while permitting horizontal movement
C. Prevent cracking entirely
D. Act as a vapor barrier
✔ Correct: B
Rationale: Keyways (grooves) in construction joints transfer shear forces across
the joint while allowing some horizontal movement.
3|Page
, Q9.
Nevada’s soil conditions often include expansive clay. What foundation
reinforcement is most effective?
A. Wire mesh only
B. Increased vapor barrier
C. Post-tensioned tendons or additional rebar
D. Lightweight aggregate
✔ Correct: C
Rationale: Post-tensioning or increased steel reinforcement resists tensile forces
from expansive soil movement. Standard mesh alone is insufficient.
Q10.
The maximum time allowed between adding mixing water and completing
concrete placement (Nevada hot weather) is typically:
A. 30 minutes
B. 90 minutes
C. 3 hours
D. 6 hours
✔ Correct: B
Rationale: ACI 301 limits transit/placement time to 90 minutes (or sooner in
heat). Extended time reduces strength and workability.
Q11.
What tool is used to create a broom finish on a concrete driveway?
A. Bull float
B. Broom with stiff bristles
C. Power trowel
D. Groover
✔ Correct: B
Rationale: A stiff-bristle broom dragged across fresh concrete creates a slip-
resistant texture. Float and trowel produce smooth surfaces.
4|Page
