ATT Sampling Aggregates 4

Question 1

What does 'nominal maximum size' of an aggregate refer to in the context of sampling?

Accepted Answer

The smallest sieve that retains more than 10% of the material

Answer

Nominal maximum size is the smallest sieve opening through which the entire amount of aggregate is permitted to pass, retaining no more than 10% on that sieve.

Question 2

Why must sampling equipment be clean and free of residue before collecting an aggregate sample?

Accepted Answer

Residue from previous samples can contaminate and alter gradation or test results

Answer

Contamination from previous samples can alter the particle size distribution, chemical composition, or moisture content of the new sample.

Question 3

What action should be taken if a field sample arrives at the laboratory with obvious segregation in the container?

Accepted Answer

Re-mix the entire container thoroughly before reducing the sample

Answer

ASTM C702 requires thorough remixing before reduction to reintegrate any segregated particles and restore the sample's representativeness.

Question 4

The riffle splitter (mechanical sample splitter) divides a sample by:

Accepted Answer

Directing alternating chutes of material into two equal pans

Answer

A riffle splitter has an even number of chutes that alternate direction, splitting the stream into two roughly equal halves by mass.

Question 5

When quartering aggregate by hand, after dividing the sample into four equal parts, which portions are retained for the test sample?

Accepted Answer

Two opposite quadrants

Answer

Quartering retains two diagonally opposite quadrants, which together represent the original sample, while discarding the other two opposite quadrants.

(ATT) ACI Aggregate Testing Technician Practice Test

(ATT) ACI Aggregate Testing Technician Practice Test

ATT Sampling Aggregates 4