Practice Test Geeks(ATT) ACI Aggregate Testing Technician Practice Test
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Unit Weight & Voids Testing Flashcards

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

Read the first 7 Unit Weight & Voids Testing flashcards as text

  1. In the unit weight test, why is it important to avoid vibrating the measure during filling?

    Answer: Vibration increases packing beyond the standard procedure, giving artificially high results

    External vibration compacts aggregate beyond what the standard procedure intends, producing a unit weight higher than the standardized result.

  2. What is the minimum size of measure required for aggregate with a nominal maximum size of 1.5 inches per ASTM C29?

    Answer: 1 cubic foot

    ASTM C29 requires a 1-cubic-foot measure when the aggregate nominal maximum size is 1.5 inches.

  3. Which of the following conditions would cause the measured unit weight of coarse aggregate to be lower than the true value?

    Answer: Having a dented or deformed measure that increases its volume

    A deformed measure with a larger-than-calibrated volume holds more aggregate, making the calculated unit weight (mass/volume) artificially low.

  4. The voids-in-aggregate formula uses the term 'W' to represent what quantity?

    Answer: Bulk unit weight of the aggregate

    In ASTM C29, W is the bulk unit weight (unit weight) of the aggregate determined by the standard test.

  5. According to ASTM C29, what is the standard number of drops of the measure against the base when using the jigging compaction method?

    Answer: 50 drops per layer

    The jigging method requires the measure to be raised and dropped 50 times per layer as specified in ASTM C29.

  6. If a technician uses the jigging method instead of rodding for fine aggregate, what effect does this typically have?

    Answer: Results may be slightly different but both are acceptable methods under ASTM C29

    ASTM C29 permits both rodding and jigging; either method is acceptable and results may differ slightly but remain valid.

  7. A unit weight measure is calibrated by filling it with water at a known temperature. What property of water is used to calculate the volume of the measure?

    Answer: Unit weight (density)

    The unit weight (density) of water at the test temperature is used along with the mass of water to calculate the volume (V = mass/density).