Practice Test Geeks(ACI) American Concrete Institute Concrete Finisher Practice Test
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Flatwork Placement & Leveling Flashcards

7 cards from real ACI practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Flatwork Placement & Leveling flashcards as text

  1. What is the recommended maximum free-fall height when depositing concrete to minimize segregation?

    Answer: 3 feet

    ACI guidelines recommend limiting free-fall to no more than 3 feet to prevent coarse aggregate from separating from the mortar.

  2. When screedng concrete between forms, the screed should be moved with what motion?

    Answer: A sawing side-to-side motion while advancing forward

    A sawing back-and-forth lateral motion while advancing forward fills voids and levels the surface without leaving ridges.

  3. What is 'subgrade drag' and why does it matter during flatwork placement?

    Answer: Friction between the subgrade and concrete slab that can cause cracking as the slab shrinks

    Subgrade drag is the restraint force between the slab and subgrade that resists shrinkage movement, potentially causing cracking if not relieved by joints or proper subgrade preparation.

  4. Which type of screed is best suited for large flatwork areas requiring high flatness tolerances (high FF numbers)?

    Answer: Laser-guided or GPS-controlled vibratory screed

    Laser-guided or GPS-controlled vibratory screeds provide the precision and consistency needed to achieve high FF/FL tolerances on large slab areas.

  5. When pumping concrete for flatwork, the discharge hose should be positioned to deposit concrete:

    Answer: As close to final position as possible to minimize movement

    Depositing near the final position minimizes the need to rake or move concrete, reducing the risk of segregation and maintaining mix uniformity.

  6. What is the purpose of 'strike-off' in concrete flatwork?

    Answer: Removing excess concrete to bring the surface to the level of the forms or screed guides

    Strike-off (screeding) removes excess concrete and brings the surface to the required grade established by the form tops or screed guides.

  7. In cold-weather concreting, what minimum concrete temperature (as delivered) does ACI 306 recommend for sections 12 inches or less?

    Answer: 55°F (13°C)

    ACI 306 requires a minimum delivered concrete temperature of 55°F (13°C) for thin sections up to 12 inches to ensure adequate hydration and strength gain.