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 C117

Answer

ASTM C131

Answer

ASTM C136

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

1 to 4 hours

Answer

48 hours minimum

Answer

12 ± 1 hours

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

By color change

Answer

By measuring density change

Answer

By sieve washing only

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

1.0%

Answer

2.0%

Answer

5.0%

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

No. 8 (2.36 mm)

Answer

No. 16 (1.18 mm)

Answer

3/8 in. (9.5 mm)

Question 6

Which deleterious substance in aggregate is most likely to cause unsightly staining and pop-outs in hardened concrete?

Accepted Answer

Coal and lignite particles

Answer

Rounded quartz particles

Answer

Well-graded limestone fines

Answer

Crushed glass