NETTCP Lab Testing Procedures 3

Question 1

The Modified Proctor compaction test (AASHTO T 180) differs from the Standard Proctor primarily in its:

Accepted Answer

Number of soil layers and hammer energy

Answer

AASHTO T 180 uses 5 layers and a 10-lb hammer dropped 18 inches, resulting in about 4.5 times the compaction energy of the Standard Proctor.

Question 2

When testing aggregate for flat and elongated particles per ASTM D 4791, a particle is considered elongated if its longest dimension exceeds its shortest dimension by a ratio of:

Accepted Answer

3:1

Answer

ASTM D 4791 defines elongated particles as those with a length-to-thickness ratio exceeding 3:1 at the specified ratio being tested.

Question 3

Which equipment is used to measure the air content of freshly mixed concrete by the pressure method per AASHTO T 152?

Accepted Answer

Air entrainment meter (Type B pressure meter)

Answer

The Type B pressure meter (air meter) applies a known pressure to the concrete sample and measures the volume change to calculate air content.

Question 4

A soil sample has a wet mass of 450 g and a dry mass of 380 g. What is the moisture content?

Accepted Answer

18.4%

Answer

Moisture content = (wet mass − dry mass) / dry mass × 100 = (450 − 380) / 380 × 100 = 18.4%.

Question 5

During a Marshall stability test on compacted asphalt specimens, the loading rate specified by AASHTO T 245 is:

Accepted Answer

2 in/min

Answer

AASHTO T 245 requires a constant deformation rate of 2 inches per minute (50 mm/min) when determining Marshall stability and flow.

(NETTCP) New England Transportation Technician Certification Program Practice Test

(NETTCP) New England Transportation Technician Certification Program Practice Test

NETTCP Lab Testing Procedures 3