CCIL Aggregate Gradation and Properties 2

Question 1

What does the term 'fineness modulus' represent in aggregate testing?

Accepted Answer

A single number representing the average size of particles in a sand sample

Answer

Fineness modulus is computed by summing cumulative percentages retained on a standard sieve series and dividing by 100, yielding a number that represents the average particle size of a sand sample.

Question 2

According to ASTM C136, sieve analysis of aggregates requires that each sieve be shaken for a minimum of how many minutes?

Accepted Answer

1 minute

Answer

ASTM C136 requires that sieving continue until no more than 1% of the retained material passes the sieve in 1 minute of hand sieving.

Question 3

Which sieve size is used to separate coarse aggregate from fine aggregate in standard practice?

Accepted Answer

No. 4 (4.75 mm)

Answer

The No. 4 (4.75 mm) sieve is the standard dividing line between coarse aggregate and fine aggregate per ASTM definitions.

Question 4

What is the primary purpose of performing a wash sieve analysis before dry sieve analysis?

Accepted Answer

To remove clay, silt, and dust coatings that could blind sieves

Answer

Washing the sample before sieve analysis removes clay, silt, and dust that would otherwise clog or blind the sieve openings and give inaccurate gradation results.

Question 5

Gap-graded aggregate is characterized by which of the following gradation patterns?

Accepted Answer

An absence of intermediate particle sizes, with concentrations at coarse and fine ends

Answer

Gap-graded aggregate lacks particles in one or more intermediate size ranges, resulting in a gradation curve with a near-horizontal (flat) section.

CCIL - Canadian Council of Independent Laboratories Practice Test

CCIL - Canadian Council of Independent Laboratories Practice Test

CCIL Aggregate Gradation and Properties 2