NETTCP Soils and Aggregates 2

Question 1

According to AASHTO classification, a soil with a group index of 0 indicates:

Accepted Answer

Good subgrade material

Answer

A group index of 0 indicates a good subgrade material with minimal potential for poor performance.

Question 2

Which sieve size is used to separate fine aggregate from coarse aggregate in AASHTO testing?

Accepted Answer

No. 4 (4.75 mm)

Answer

The No. 4 sieve (4.75 mm) is the standard dividing line between fine and coarse aggregate.

Question 3

What does a high Los Angeles abrasion loss percentage indicate about aggregate quality?

Accepted Answer

Low resistance to wear and degradation

Answer

A high LA abrasion loss percentage means the aggregate breaks down easily under impact and abrasion, indicating poor durability.

Question 4

The shrinkage limit of a soil is defined as the water content at which:

Accepted Answer

Further drying causes no additional volume change

Answer

The shrinkage limit is the water content below which no further volume change occurs as the soil dries.

Question 5

In a sieve analysis, if 15% of aggregate passes the No. 200 sieve, this material is classified as:

Accepted Answer

Aggregate likely exceeding fines limits for base course

Answer

Most NETTCP base course specifications limit minus No. 200 material to around 8–12%, so 15% likely exceeds allowable fines.

(NETTCP) New England Transportation Technician Certification Program Practice Test