Practice Test Geeks(ATT) ACI Aggregate Testing Technician Practice Test
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Moisture Content 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.

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  1. The 'free moisture' (surface moisture) of aggregate is calculated as:

    Answer: Total moisture content minus absorption capacity

    Free moisture = total moisture content − absorption capacity; it represents the water that will add to the mix water in a concrete batch.

  2. Which ASTM standard governs the test method for total evaporable moisture content of aggregate by drying?

    Answer: ASTM C566

    ASTM C566 is the standard test method specifically for total evaporable moisture content of aggregate by drying.

  3. A stockpile of coarse aggregate is sampled at three locations: top, middle, and side. Why are multiple locations sampled?

    Answer: Because moisture content can vary significantly at different points in a stockpile

    Moisture tends to drain downward, making lower or interior portions of a stockpile wetter than the top or sides.

  4. When calculating the batch water for a concrete mix, the free moisture in the aggregate must be:

    Answer: Subtracted from the design water content

    Free moisture in aggregates will contribute water to the mix, so it must be subtracted from the design (added) water to maintain the correct water-cement ratio.

  5. An oven used for moisture content testing of aggregate must be checked for temperature uniformity. What tool is used to verify oven temperature?

    Answer: A calibrated thermometer or thermocouple

    A calibrated thermometer or thermocouple is placed inside the oven to verify it maintains 110 ± 5°C throughout the drying cycle.

  6. When is aggregate considered 'oven-dry' during a moisture content test?

    Answer: When successive weighings at 1-hour intervals show less than 0.1% change in mass

    ASTM C566 requires drying until successive weighings (after additional drying intervals) differ by less than 0.1% of the specimen mass, confirming constant mass.

  7. What effect does high aggregate moisture content have on concrete workability if no adjustment is made to the batch water?

    Answer: Workability increases because total water content is higher than designed

    Unadjusted high aggregate moisture adds excess water to the mix, increasing the water-cement ratio and workability but reducing strength.