ATT ATT Deleterious Materials & Clay Content

Question 1

Which ASTM standard covers the test method for clay lumps and friable particles in aggregates?

Accepted Answer

ASTM C142

Answer

ASTM C142 is the standard test method for clay lumps and friable particles in aggregates.

Question 2

In the clay lumps and friable particles test (ASTM C142), the sample is soaked in water for a period of:

Accepted Answer

24 ± 4 hours

Answer

ASTM C142 requires soaking the sample in water for 24 ± 4 hours before attempting to break particles with the fingers.

Question 3

After soaking in ASTM C142, how are clay lumps and friable particles identified?

Accepted Answer

By attempting to crumble them between thumb and forefinger

Answer

Particles that can be broken down by rubbing between the thumb and forefinger after soaking are classified as clay lumps or friable particles.

Question 4

According to ASTM C33, the maximum allowable clay lumps and friable particles in fine aggregate for concrete is:

Accepted Answer

3.0%

Answer

ASTM C33 limits clay lumps and friable particles in fine aggregate to a maximum of 3.0% by mass.

Question 5

What sieve size is used to separate the material retained for the clay lumps test in coarse aggregate per ASTM C142?

Accepted Answer

No. 4 (4.75 mm)

Answer

For coarse aggregate, ASTM C142 testing uses material retained on the No. 4 (4.75 mm) sieve.

(ATT) ACI Aggregate Testing Technician Practice Test