NETTCP Sampling Methods 2

Question 1

When sampling hot mix asphalt (HMA) from a truck, which location in the load is generally AVOIDED to reduce segregation bias?

Accepted Answer

Top surface directly beneath the chute

Answer

Material directly beneath the truck's discharge chute tends to be coarser due to segregation and is avoided when sampling.

Question 2

What AASHTO standard governs the sampling of aggregates for road and bridge construction?

Accepted Answer

AASHTO T 2

Answer

AASHTO T 2 is the standard method of sampling aggregates.

Question 3

A technician needs a 5 kg sample but the field sample yielded 20 kg. What process reduces the sample to the required size?

Accepted Answer

Quartering or splitting

Answer

Mechanical splitting or the quartering method is used to reduce a large field sample to a representative test sample.

Question 4

For soils testing on a highway project, a random sampling plan is preferred over convenience sampling primarily because it:

Accepted Answer

Eliminates operator bias in sample location selection

Answer

Random sampling removes operator bias, ensuring that every location has an equal probability of being selected.

Question 5

Which equipment is used for mechanical sample splitting of fine-grained soils and aggregates to ensure representative reduction?

Accepted Answer

Riffle splitter (sample splitter)

Answer

A riffle splitter divides a sample into two equal halves by directing material alternately into opposite chutes.

(NETTCP) New England Transportation Technician Certification Program Practice Test