CCIL Aggregate Gradation and Properties 3

Question 1

What does 'bulk specific gravity (SSD)' mean in the context of aggregate testing?

Accepted Answer

The ratio of the SSD mass to the mass of an equal volume of water including permeable pores

Answer

Bulk specific gravity (SSD) is the ratio of the saturated surface-dry mass of aggregate to the mass of an equal volume of water, including the volume of permeable pores.

Question 2

What is the flat and elongated particle ratio used to assess?

Accepted Answer

Aggregate particle shape and potential for crushing under load

Answer

Flat and elongated particles are more susceptible to breaking under compaction loads, and their ratio is measured to assess aggregate durability and compactability in pavement construction.

Question 3

Which ASTM test method is used to determine the unit weight and voids in aggregate?

Accepted Answer

ASTM C29

Answer

ASTM C29 covers the standard test method for bulk density (unit weight) and voids in aggregate using rodding, jigging, or shoveling procedures.

Question 4

What is the purpose of the aggregate soundness test (ASTM C88)?

Accepted Answer

To evaluate the resistance of aggregate to weathering by freeze-thaw or wetting-drying cycles

Answer

The soundness test uses sodium or magnesium sulfate solution to simulate weathering and assess whether aggregate will deteriorate when exposed to freeze-thaw cycling in service.

Question 5

Which aggregate property most directly affects the workability and water demand of a concrete mix?

Accepted Answer

Aggregate gradation and particle shape

Answer

Aggregate gradation and particle shape directly influence void content in the mix; gap-graded or angular aggregates increase void content and water demand, reducing workability.

CCIL - Canadian Council of Independent Laboratories Practice Test

CCIL - Canadian Council of Independent Laboratories Practice Test

CCIL Aggregate Gradation and Properties 3