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100+ Free C-8 Concrete Practice Questions

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Key Facts: C-8 Concrete Exam

3.5

Hours Time Limit

CSLB

28%

Planning and Estimating

CSLB Outline

28%

Pre-placement Preparation

CSLB Outline

17%

Safety

CSLB Outline

$450

Application Fee

CSLB

The C-8 Concrete exam is a 3.5-hour computer-delivered test administered by PSI. It requires 4 years of qualifying journey-level experience and a $450 application fee. Key topics include Planning and Estimating (28%), Pre-placement Preparation (28%), Placing and Finishing (19%), Post-placement Tasks (8%), and Safety (17%).

Sample C-8 Concrete Practice Questions

Try these sample questions to test your C-8 Concrete exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1A contractor is estimating concrete for a slab-on-grade measuring 40 feet wide by 60 feet long and 6 inches thick. Factoring in an industry-standard 10% waste allowance, how many cubic yards of concrete must be ordered?
A.48.9 cubic yards of concrete
B.44.4 cubic yards of concrete
C.53.3 cubic yards of concrete
D.40.0 cubic yards of concrete
Explanation: To calculate net slab volume: 40 ft x 60 ft x 0.5 ft = 1,200 cubic feet. Divide by 27 to convert to cubic yards: 1,200 / 27 = 44.44 cubic yards. Applying the 10% waste factor: 44.44 x 1.10 = 48.89 cubic yards, which rounds to 48.9 cubic yards.
2A continuous perimeter footing measures 250 linear feet in total length, 18 inches wide, and 12 inches deep. Including a 5% waste allowance, what total volume of concrete should be estimated?
A.16.3 cubic yards of concrete
B.14.6 cubic yards of concrete
C.13.9 cubic yards of concrete
D.18.2 cubic yards of concrete
Explanation: Convert dimensions to feet: width = 1.5 ft, depth = 1.0 ft. Volume = 250 ft x 1.5 ft x 1.0 ft = 375 cubic feet. Convert to cubic yards: 375 / 27 = 13.89 cubic yards. Adding 5% waste: 13.89 x 1.05 = 14.58 cubic yards, which rounds to 14.6 cubic yards.
3A foundation plan calls for 12 cylindrical caissons, each 24 inches in diameter and 8 feet deep. Adding a 5% waste factor, how many cubic yards of concrete are required?
A.14.8 cubic yards of concrete
B.08.9 cubic yards of concrete
C.11.7 cubic yards of concrete
D.15.4 cubic yards of concrete
Explanation: Radius = 1 ft, height = 8 ft. Volume per caisson = pi x r^2 x h = 3.1416 x (1)^2 x 8 = 25.13 cubic feet. Total net volume for 12 caissons = 12 x 25.13 = 301.6 cubic feet. Convert to cubic yards: 301.6 / 27 = 11.17 cubic yards. With 5% waste: 11.17 x 1.05 = 11.73 cubic yards, rounding to 11.7 cubic yards.
4A foundation drawing requires 12 continuous runs of #5 rebar in a 200-foot footing. Each run has 4 lap splices requiring 30 inches of overlap. Knowing #5 rebar weighs 1.043 lbs/ft, what is the total estimated rebar weight?
A.2,503 lbs of reinforcement
B.2,784 lbs of reinforcement
C.3,129 lbs of reinforcement
D.2,628 lbs of reinforcement
Explanation: Each run has 200 ft plus 4 splices at 2.5 ft (30 in) each = 200 + 10 = 210 ft. Total linear feet for 12 runs = 12 x 210 = 2,520 ft. Total weight = 2,520 ft x 1.043 lbs/ft = 2,628.36 lbs, which rounds to 2,628 lbs.
5A concrete mix design contains 564 lbs of Type II Portland cement and 225 lbs of mixing water per cubic yard. What is the calculated water-cement (w/c) ratio of this concrete mix?
A.0.40 water-cement ratio
B.0.45 water-cement ratio
C.0.35 water-cement ratio
D.0.50 water-cement ratio
Explanation: The water-cement ratio is calculated by dividing total water weight by total cement weight: 225 lbs / 564 lbs = 0.3988, which rounds to 0.40. Per ACI 318 and CBC Chapter 19, controlling w/c ratio is critical for strength and durability.
6When estimating formwork for a retaining wall stem measuring 80 feet long by 10 feet high, what is the total Square Feet of Contact Area (SFCA) requiring formwork?
A.0,800 SFCA of formwork
B.1,600 SFCA of formwork
C.2,400 SFCA of formwork
D.3,200 SFCA of formwork
Explanation: Formwork contact area includes both faces of the wall stem. Surface area per face = 80 ft x 10 ft = 800 sq ft. Since both sides require formwork: 800 sq ft x 2 = 1,600 SFCA.
7A slab-on-grade requires a grid of #4 rebar spaced at 12 inches on center in both directions over a 50 ft by 50 ft area. Knowing #4 rebar weighs 0.668 lbs/ft, what is the estimated weight of steel excluding laps?
A.1,703 lbs of steel rebar
B.5,100 lbs of steel rebar
C.3,407 lbs of steel rebar
D.2,550 lbs of steel rebar
Explanation: A 50 ft span with bars at 12 in (1 ft) spacing requires 51 bars in each direction. Total bars = 51 x 2 = 102 bars. Total linear feet = 102 bars x 50 ft = 5,100 linear feet. Total weight = 5,100 ft x 0.668 lbs/ft = 3,406.8 lbs, rounding to 3,407 lbs.
8Per ACI 318-19 and CBC Chapter 19, what is the maximum permitted water-cementitious materials ratio for structural concrete exposed to severe freezing and thawing in a moist condition (Exposure Class F2)?
A.0.50 maximum w/c ratio
B.0.40 maximum w/c ratio
C.0.55 maximum w/c ratio
D.0.45 maximum w/c ratio
Explanation: ACI 318-19 Exposure Class F2 covers concrete with frequent exposure to moisture during freezing-and-thawing cycles, mandating a maximum water-cementitious materials ratio of 0.45 and a minimum compressive strength of 4,500 psi. The low w/cm restricts permeability so that less water can infiltrate the matrix, reducing freeze-thaw damage risk. Note that F3 (which adds deicing chemical exposure) requires an even lower w/cm of 0.40 for reinforced concrete, making 0.45 the correct threshold specifically for F2 conditions.
9According to ACI 347R, what is the estimated maximum lateral pressure on wall forms for concrete placed at a rate of 4 ft/hr at a concrete temperature of 70 degrees Fahrenheit?
A.664 lbs/sq ft pressure
B.850 lbs/sq ft pressure
C.450 lbs/sq ft pressure
D.950 lbs/sq ft pressure
Explanation: Using ACI 347 formula for rate R <= 7 ft/hr: P = 150 + [9,000 x R / T]. Substituting: P = 150 + [9,000 x 4 / 70] = 150 + 514.29 = 664.29 psf, rounding to 664 lbs/sq ft.
10A structural plan specifies #6 reinforcing bars with a required Class B lap splice of 40 bar diameters (40db). What is the minimum lap splice length required?
A.24 inches minimum lap
B.30 inches minimum lap
C.36 inches minimum lap
D.20 inches minimum lap
Explanation: The nominal diameter db of #6 rebar is 6/8 inch = 0.75 inches. Minimum lap length = 40 x 0.75 in = 30 inches. ACI 318 and CBC Chapter 19 govern lap splice lengths based on bar diameter.

About the C-8 Concrete Exam

The C-8 Concrete examination evaluates a candidate's knowledge of planning and estimating, pre-placement preparation, placing and finishing, post-placement tasks, and safety protocols essential for concrete contracting in California.

Assessment

Question count not published by the exam provider

Time Limit

3.5 hours

Passing Score

Disclosed at test site

Exam Fee

$450 application fee (California Contractors State License Board (CSLB))

C-8 Concrete Exam Content Outline

28%

Planning and Estimating

Evaluating plans, specifications, and estimating materials, labor, and equipment for concrete projects.

28%

Pre-placement Preparation

Site preparation, formwork, reinforcement, and pre-pour inspections in accordance with California codes.

19%

Placing and Finishing

Transporting, pouring, consolidating, and finishing concrete surfaces to meet required tolerances.

8%

Post-placement Tasks

Curing, protecting, and evaluating concrete post-pour, including form removal and defect repair.

17%

Safety

Adhering to Cal/OSHA Title 8 safety regulations, including PPE, hazardous materials, and safe equipment operation.

How to Pass the C-8 Concrete Exam

What You Need to Know

  • Passing score: Disclosed at test site
  • Assessment: Question count not published by the exam provider
  • Time limit: 3.5 hours
  • Exam fee: $450 application fee

Keys to Passing

  • Work through all 100 available questions
  • Review every answer and explanation
  • Track weak areas and revisit them
  • Use our AI tutor for tough concepts

C-8 Concrete Study Tips from Top Performers

1Review the official CSLB C-8 Concrete Study Guide thoroughly.
2Familiarize yourself with Cal/OSHA Title 8 safety regulations.
3Practice material takeoff and labor estimation calculations.
4Understand the California Building Code (CBC) provisions related to concrete.
5Study ACI standards for concrete placing, finishing, and curing.

Frequently Asked Questions

How long is the C-8 Concrete exam?

The examination is 3.5 hours long and is delivered on a computer at a PSI testing center.

What are the experience requirements for the C-8 license?

You must have at least 4 years of qualifying journey-level experience in the concrete trade within the last 10 years.

How much does it cost to apply for the C-8 exam?

The application fee for the CSLB exams is $450.

What is the passing score for the C-8 exam?

The passing score is determined by a standard setting process and is disclosed at the test site.