ATT Moisture Content Testing 2

Question 1

When drying aggregate in an oven for moisture content determination, what is the required drying temperature per ASTM C566?

Accepted Answer

110 ± 5°C (230 ± 9°F)

Answer

ASTM C566 specifies a drying temperature of 110 ± 5°C (230 ± 9°F) to evaporate free moisture without decomposing the aggregate.

Question 2

Total moisture content of aggregate is defined as:

Accepted Answer

The sum of absorbed moisture and surface moisture

Answer

Total moisture content includes both the absorbed moisture within pores and the free (surface) moisture on the outside of particles.

Question 3

A coarse aggregate sample has a wet mass of 2,050 g and an oven-dry mass of 2,000 g. What is the moisture content?

Accepted Answer

2.5%

Answer

Moisture content = (2,050 − 2,000) / 2,000 × 100 = 50 / 2,000 × 100 = 2.5%.

Question 4

Which of the following conditions describes aggregate that has no surface moisture but has absorbed water filling its permeable pores?

Accepted Answer

Saturated surface-dry (SSD)

Answer

Saturated surface-dry (SSD) aggregate has all internal pores filled with water but no free water on the surface.

Question 5

Why is it important to seal or cover the aggregate sample tightly immediately after sampling for moisture content?

Accepted Answer

To prevent evaporation of moisture before testing

Answer

Moisture can evaporate quickly from a sample, causing erroneously low moisture content readings if the sample is not sealed promptly.

(ATT) ACI Aggregate Testing Technician Practice Test