Aggregate Sampling & Reduction Flashcards
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Read the first 7 Aggregate Sampling & Reduction flashcards as text
According to ASTM C702, when performing mechanical splitting, what action should be taken if material bridges across the chutes of the splitter?
Answer: Stop the process, clear the bridge, and re-run the material through
If bridging occurs in the splitter chutes, the material should be retrieved, the bridge cleared, and the increment re-run to ensure the full quantity passes through.
The 'increment' in ASTM D75 sampling terminology is defined as:
Answer: A single portion of material collected in one sampling operation
An increment is a single portion of material collected at one time from one location; multiple increments are combined to form the composite sample.
For aggregate sampled from flowing streams (chutes or discharge points), the preferred device to collect the full width of material flow is:
Answer: A full-width sampling frame or pan that intercepts the entire stream
A sampling device that spans the full width of the flowing stream ensures all particle sizes are captured without size-biased collection.
When reducing a coarse aggregate field sample by quartering, what should be done to the pile before dividing it into quarters?
Answer: Mix the material thoroughly and flatten it into a uniform circular pile
The material must be thoroughly mixed and formed into a flat, uniform circular pile before dividing, to ensure each quarter contains a representative distribution of sizes.
What is the significance of the 'nominal maximum size' of aggregate when determining the required field sample mass per ASTM D75?
Answer: Larger nominal maximum size requires a larger minimum field sample mass
ASTM D75 requires larger minimum sample masses for aggregates with larger nominal maximum sizes to ensure statistical representativeness of coarse particles.
Which ASTM standard specifically governs the practice of reducing field samples of aggregate to testing size in the laboratory?
Answer: ASTM C702
ASTM C702 is the standard practice covering methods for reducing field samples of aggregate to testing size, including mechanical splitting and quartering.
When collecting samples from aggregate bins or hoppers, where within the bin should sampling be avoided?
Answer: The sides and corners where material stagnates and may not be representative
Material at the sides and corners of bins can be stagnant, degraded, or segregated, making it unrepresentative of the material being discharged for use.