ATT Aggregate Sampling & Reduction 4

Question 1

According to ASTM C702, when performing mechanical splitting, what action should be taken if material bridges across the chutes of the splitter?

Accepted Answer

Stop the process, clear the bridge, and re-run the material through

Answer

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.

Question 2

The 'increment' in ASTM D75 sampling terminology is defined as:

Accepted Answer

A single portion of material collected in one sampling operation

Answer

An increment is a single portion of material collected at one time from one location; multiple increments are combined to form the composite sample.

Question 3

For aggregate sampled from flowing streams (chutes or discharge points), the preferred device to collect the full width of material flow is:

Accepted Answer

A full-width sampling frame or pan that intercepts the entire stream

Answer

A sampling device that spans the full width of the flowing stream ensures all particle sizes are captured without size-biased collection.

Question 4

When reducing a coarse aggregate field sample by quartering, what should be done to the pile before dividing it into quarters?

Accepted Answer

Mix the material thoroughly and flatten it into a uniform circular pile

Answer

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.

Question 5

What is the significance of the 'nominal maximum size' of aggregate when determining the required field sample mass per ASTM D75?

Accepted Answer

Larger nominal maximum size requires a larger minimum field sample mass

Answer

ASTM D75 requires larger minimum sample masses for aggregates with larger nominal maximum sizes to ensure statistical representativeness of coarse particles.

(ATT) ACI Aggregate Testing Technician Practice Test

(ATT) ACI Aggregate Testing Technician Practice Test

ATT Aggregate Sampling & Reduction 4