ATT ATT Flat, Elongated Particles & Sand Equivalent

Question 1

Which ASTM standard covers the test method for flat particles, elongated particles, or flat and elongated particles in coarse aggregate?

Accepted Answer

ASTM D4791

Answer

ASTM C131

Answer

ASTM C142

Answer

ASTM C29

Question 2

In ASTM D4791, a particle is classified as 'flat' when the ratio of its width to thickness exceeds:

Accepted Answer

3:1

Answer

2:1

Answer

5:1

Answer

10:1

Question 3

Why are flat and elongated particles undesirable in concrete aggregate?

Accepted Answer

They tend to orient horizontally and create planes of weakness, increasing water demand

Answer

They reduce water demand significantly

Answer

They improve workability of fresh concrete

Answer

They have higher specific gravity

Question 4

The proportional caliper device used in ASTM D4791 testing measures:

Accepted Answer

The ratio between two dimensions of a particle

Answer

The mass of individual particles

Answer

The surface area of particles

Answer

The volume of particles

Question 5

In ASTM D4791, what is the minimum number of particles required for a valid flat and elongated test?

Accepted Answer

100 particles

Answer

50 particles

Answer

200 particles

Answer

500 particles

Question 6

A particle classified as 'flat and elongated' in ASTM D4791 has a ratio of its maximum dimension to its minimum dimension exceeding:

Accepted Answer

5:1

Answer

2:1

Answer

3:1

Answer

1.5:1