2026 UPDATED QUESTIONS DOWNLOAD
Nevada Concrete Contractor (C-5) Contractor Practice
Exam
Prepare for the Nevada C-5 Concrete Contractor license with this comprehensive 350-question study
guide featuring detailed italicized rationales. This bundle covers all critical domains, including Nevada
CMS (Business/Law) and C-5 Technical standards (ACI/IBC), mix design, rebar placement, and
Nevada-specific sulfate-resistant cement requirements. Master the most difficult board concepts
like slump testing, cold weather pouring, and Nevada NRS 624 compliance to ensure a first-time
pass.
1. According to ACI 318, what is the minimum concrete cover for reinforcing steel in a
footing cast against and permanently exposed to earth?
A. 1.5 inches
B. 2 inches
C. 3 inches
D. 4 inches
Rationale: C. 3 inches. High moisture and mineral content in soil require a thicker barrier of
concrete to prevent rebar corrosion.
2. A "Slump Test" measures which property of freshly mixed concrete?
A. Compressive strength
B. Tensile strength
C. Consistency and workability
D. Air content
Rationale: C. Consistency and workability. The test measures how much the concrete
"slumps" under its own weight, indicating its fluidness/wetness.
3. What is the primary purpose of "Air-Entraining" admixtures in concrete?
A. To make the concrete lighter
B. To improve resistance to freeze-thaw cycles
C. To increase the 28-day compressive strength
D. To reduce the setting time
Rationale: B. Freeze-thaw resistance. Microscopic bubbles provide space for water to expand
when it freezes, preventing surface scaling.
4. How many cubic yards of concrete are needed for a slab 30’ long, 20’ wide, and 6”
thick?
A. 11.11 cubic yards
, 2026 UPDATED QUESTIONS DOWNLOAD
B. 13.50 cubic yards
C. 15.25 cubic yards
D. 18.00 cubic yards
Rationale: A. 11.11 cubic yards. Calculation: (30 x 20 x 0.5) / 27 = 11.11. (Note: 6 inches = 0.5
feet).
5. What is the main cause of "Crazing" (fine hair-line cracks) on a concrete surface?
A. Lack of rebar
B. Rapid surface drying due to low humidity or wind
C. Using too much large aggregate
D. Walking on the concrete too early
Rationale: B. Rapid surface drying. When the surface dries significantly faster than the
underlying concrete, these spider-web-like cracks appear.
6. When finishing a slab, "Bleed Water" should be:
A. Worked back into the surface with a power trowel
B. Sopped up with a sponge immediately
C. Allowed to evaporate or be removed before final finishing
D. Mixed with dry cement to thicken the top layer
Rationale: C. Allowed to evaporate. Working bleed water back into the surface weakens the
top layer and causes dusting or scaling.
7. "Honeycombing" in a concrete wall is usually caused by:
A. Too much vibration
B. Inadequate vibration or poor consolidation
C. High water-to-cement ratio
D. Using too much sand
Rationale: B. Inadequate vibration. This prevents the mortar from filling the spaces between
the large aggregates.
8. What is the standard "Curing Time" for concrete to reach its design strength for
testing purposes?
A. 3 days
B. 7 days
C. 28 days
D. 90 days
Rationale: C. 28 days. While concrete continues to gain strength for years, 28 days is the
industry standard for verifying the specified PSI.
9. A "Vapor Barrier" is typically placed:
A. On top of the finished slab
B. Between the subgrade and the concrete slab
C. Inside the formwork for walls
D. Between two layers of rebar
, 2026 UPDATED QUESTIONS DOWNLOAD
Rationale: B. Between the subgrade and the slab. This prevents moisture from the ground
from wicking up through the porous concrete into the building.
10. Which type of cement is "Sulfate-Resistant" and often used in Nevada soils with
high mineral content?
A. Type I
B. Type II or Type V
C. Type III
D. White Cement
Rationale: B. Type II (Moderate) or Type V (High Sulfate Resistance). Nevada's alkaline soils
can chemically attack concrete unless sulfate-resistant cement is used.
11. The process of leveling the top of the concrete with a straightedge immediately after
pouring is called:
A. Troweling
B. Floating
C. Screeding (or Striking off)
D. Edging
Rationale: C. Screeding. This is the first step in finishing, establishing the correct grade and
level.
12. To prevent "Segregation" when pouring concrete from a high height, the maximum
free-fall distance should generally be:
A. 3 to 5 feet
B. 10 feet
C. 15 feet
D. There is no limit
Rationale: A. 3 to 5 feet. Falling from greater heights causes the heavy aggregate to separate
from the mortar.
13. A "Control Joint" (Contraction Joint) should be cut to a depth of at least:
A. 1/8 the slab thickness
B. 1/4 the slab thickness
C. 1/2 the slab thickness
D. The full depth of the slab
Rationale: B. 1/4 the slab thickness. This creates a weakened plane so that when the concrete
shrinks, it cracks in a straight line at the joint.
14. What is the purpose of "Dowel Bars" in a concrete pavement joint?
A. To keep the concrete from drying
B. To transfer loads between slabs while allowing for thermal expansion
C. To replace all mesh reinforcement
D. To mark the edge of the pour
, 2026 UPDATED QUESTIONS DOWNLOAD
Rationale: B. Load transfer. Dowels allow the slabs to move horizontally but prevent vertical
shifting (faulting).
15. "Cold Weather" concreting procedures should be initiated when the air temperature
falls below:
A. 50°F
B. 40°F
C. 32°F
D. 20°F
Rationale: B. 40°F. Hydration slows significantly at low temperatures, and if fresh concrete
freezes, it can lose up to 50% of its potential strength.
16. Which admixture is used to speed up the setting time of concrete?
A. Retarder
B. Superplasticizer
C. Accelerator (e.g., Calcium Chloride)
D. Fly Ash
Rationale: C. Accelerator. These are used in cold weather to reach the initial set faster.
17. Reinforcing steel (rebar) that is "Grade 60" has a yield strength of:
A. 6,000 PSI
B. 60,000 PSI
C. 600,000 PSI
D. 60 PSI
Rationale: B. 60,000 PSI. The grade represents the minimum yield strength in thousands of
pounds per square inch.
18. What is the weight of one cubic foot of standard-weight reinforced concrete?
A. 100 lbs
B. 150 lbs
C. 200 lbs
D. 300 lbs
Rationale: B. 150 lbs. (Unreinforced concrete is roughly 145 lbs; the steel adds weight).
19. When using a "Vibrator" to consolidate concrete, you should:
A. Drag it horizontally through the forms
B. Insert it vertically and withdraw it slowly
C. Leave it in one spot for at least 5 minutes
D. Only vibrate the top 2 inches
Rationale: B. Insert vertically and withdraw slowly. Dragging it causes segregation of materials.
20. "Darbying" or "Bull Floating" is done:
A. After troweling is complete
B. Immediately after screeding to embed large aggregate and remove ridges
C. After the concrete has cured for 7 days
Nevada Concrete Contractor (C-5) Contractor Practice
Exam
Prepare for the Nevada C-5 Concrete Contractor license with this comprehensive 350-question study
guide featuring detailed italicized rationales. This bundle covers all critical domains, including Nevada
CMS (Business/Law) and C-5 Technical standards (ACI/IBC), mix design, rebar placement, and
Nevada-specific sulfate-resistant cement requirements. Master the most difficult board concepts
like slump testing, cold weather pouring, and Nevada NRS 624 compliance to ensure a first-time
pass.
1. According to ACI 318, what is the minimum concrete cover for reinforcing steel in a
footing cast against and permanently exposed to earth?
A. 1.5 inches
B. 2 inches
C. 3 inches
D. 4 inches
Rationale: C. 3 inches. High moisture and mineral content in soil require a thicker barrier of
concrete to prevent rebar corrosion.
2. A "Slump Test" measures which property of freshly mixed concrete?
A. Compressive strength
B. Tensile strength
C. Consistency and workability
D. Air content
Rationale: C. Consistency and workability. The test measures how much the concrete
"slumps" under its own weight, indicating its fluidness/wetness.
3. What is the primary purpose of "Air-Entraining" admixtures in concrete?
A. To make the concrete lighter
B. To improve resistance to freeze-thaw cycles
C. To increase the 28-day compressive strength
D. To reduce the setting time
Rationale: B. Freeze-thaw resistance. Microscopic bubbles provide space for water to expand
when it freezes, preventing surface scaling.
4. How many cubic yards of concrete are needed for a slab 30’ long, 20’ wide, and 6”
thick?
A. 11.11 cubic yards
, 2026 UPDATED QUESTIONS DOWNLOAD
B. 13.50 cubic yards
C. 15.25 cubic yards
D. 18.00 cubic yards
Rationale: A. 11.11 cubic yards. Calculation: (30 x 20 x 0.5) / 27 = 11.11. (Note: 6 inches = 0.5
feet).
5. What is the main cause of "Crazing" (fine hair-line cracks) on a concrete surface?
A. Lack of rebar
B. Rapid surface drying due to low humidity or wind
C. Using too much large aggregate
D. Walking on the concrete too early
Rationale: B. Rapid surface drying. When the surface dries significantly faster than the
underlying concrete, these spider-web-like cracks appear.
6. When finishing a slab, "Bleed Water" should be:
A. Worked back into the surface with a power trowel
B. Sopped up with a sponge immediately
C. Allowed to evaporate or be removed before final finishing
D. Mixed with dry cement to thicken the top layer
Rationale: C. Allowed to evaporate. Working bleed water back into the surface weakens the
top layer and causes dusting or scaling.
7. "Honeycombing" in a concrete wall is usually caused by:
A. Too much vibration
B. Inadequate vibration or poor consolidation
C. High water-to-cement ratio
D. Using too much sand
Rationale: B. Inadequate vibration. This prevents the mortar from filling the spaces between
the large aggregates.
8. What is the standard "Curing Time" for concrete to reach its design strength for
testing purposes?
A. 3 days
B. 7 days
C. 28 days
D. 90 days
Rationale: C. 28 days. While concrete continues to gain strength for years, 28 days is the
industry standard for verifying the specified PSI.
9. A "Vapor Barrier" is typically placed:
A. On top of the finished slab
B. Between the subgrade and the concrete slab
C. Inside the formwork for walls
D. Between two layers of rebar
, 2026 UPDATED QUESTIONS DOWNLOAD
Rationale: B. Between the subgrade and the slab. This prevents moisture from the ground
from wicking up through the porous concrete into the building.
10. Which type of cement is "Sulfate-Resistant" and often used in Nevada soils with
high mineral content?
A. Type I
B. Type II or Type V
C. Type III
D. White Cement
Rationale: B. Type II (Moderate) or Type V (High Sulfate Resistance). Nevada's alkaline soils
can chemically attack concrete unless sulfate-resistant cement is used.
11. The process of leveling the top of the concrete with a straightedge immediately after
pouring is called:
A. Troweling
B. Floating
C. Screeding (or Striking off)
D. Edging
Rationale: C. Screeding. This is the first step in finishing, establishing the correct grade and
level.
12. To prevent "Segregation" when pouring concrete from a high height, the maximum
free-fall distance should generally be:
A. 3 to 5 feet
B. 10 feet
C. 15 feet
D. There is no limit
Rationale: A. 3 to 5 feet. Falling from greater heights causes the heavy aggregate to separate
from the mortar.
13. A "Control Joint" (Contraction Joint) should be cut to a depth of at least:
A. 1/8 the slab thickness
B. 1/4 the slab thickness
C. 1/2 the slab thickness
D. The full depth of the slab
Rationale: B. 1/4 the slab thickness. This creates a weakened plane so that when the concrete
shrinks, it cracks in a straight line at the joint.
14. What is the purpose of "Dowel Bars" in a concrete pavement joint?
A. To keep the concrete from drying
B. To transfer loads between slabs while allowing for thermal expansion
C. To replace all mesh reinforcement
D. To mark the edge of the pour
, 2026 UPDATED QUESTIONS DOWNLOAD
Rationale: B. Load transfer. Dowels allow the slabs to move horizontally but prevent vertical
shifting (faulting).
15. "Cold Weather" concreting procedures should be initiated when the air temperature
falls below:
A. 50°F
B. 40°F
C. 32°F
D. 20°F
Rationale: B. 40°F. Hydration slows significantly at low temperatures, and if fresh concrete
freezes, it can lose up to 50% of its potential strength.
16. Which admixture is used to speed up the setting time of concrete?
A. Retarder
B. Superplasticizer
C. Accelerator (e.g., Calcium Chloride)
D. Fly Ash
Rationale: C. Accelerator. These are used in cold weather to reach the initial set faster.
17. Reinforcing steel (rebar) that is "Grade 60" has a yield strength of:
A. 6,000 PSI
B. 60,000 PSI
C. 600,000 PSI
D. 60 PSI
Rationale: B. 60,000 PSI. The grade represents the minimum yield strength in thousands of
pounds per square inch.
18. What is the weight of one cubic foot of standard-weight reinforced concrete?
A. 100 lbs
B. 150 lbs
C. 200 lbs
D. 300 lbs
Rationale: B. 150 lbs. (Unreinforced concrete is roughly 145 lbs; the steel adds weight).
19. When using a "Vibrator" to consolidate concrete, you should:
A. Drag it horizontally through the forms
B. Insert it vertically and withdraw it slowly
C. Leave it in one spot for at least 5 minutes
D. Only vibrate the top 2 inches
Rationale: B. Insert vertically and withdraw slowly. Dragging it causes segregation of materials.
20. "Darbying" or "Bull Floating" is done:
A. After troweling is complete
B. Immediately after screeding to embed large aggregate and remove ridges
C. After the concrete has cured for 7 days
