Practice Test Geeks(ATT) ACI Aggregate Testing Technician Practice Test
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Bulk Density, Voids & Organic Impurities Flashcards

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

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  1. What does bulk density of aggregate refer to?

    Answer: Mass per unit volume including voids

    Bulk density is the mass of aggregate required to fill a container of a specified unit volume and includes the volume of the particles and the voids between them.

  2. Which ASTM standard covers the determination of bulk density of aggregates?

    Answer: ASTM C29

    ASTM C29 is the recognized method for measuring the bulk density and void content of aggregates.

  3. Why is determining void content in aggregates important?

    Answer: To estimate cement requirements

    Void content helps assess the space between aggregate particles, influencing concrete workability and mix proportions.

  4. What is the visual indication of organic impurities in fine aggregates?

    Answer: Dark-colored solution compared to the standard

    A darker color in the solution during the ASTM C40 test indicates the possible presence of organic impurities that can affect concrete strength.

  5. Which of the following can result from excessive organic impurities in aggregates?

    Answer: Reduced concrete strength

    Excessive organic matter can interfere with cement hydration and significantly reduce the strength of hardened concrete.

  6. What is the correct procedure when testing bulk density?

    Answer: Fill using specified method such as rodding or shoveling

    The container must be filled in a standard manner—loose, rodded, or compacted—depending on the type of aggregate and test requirement.

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