Abstract： AS 1141.33:2015 pdf download.Methods for sampling and testing aggregates Method 33: Clay and fine silt (settling method). 2 .1 RINCIPLF The test method causes a sample that is a mixture of sand, silt and clay-sized particles to be agitated...

AS 1141.33:2015 pdf download.Methods for sampling and testing aggregates Method 33: Clay and fine silt (settling method).

2 .1 RINCIPLF

The test method causes a sample that is a mixture of sand, silt and clay-sized particles to be agitated in a column of a salt solution. The particles settle in the liquid and the silt and clay particles that require a longer time to settle out of the suspension, usually form a distinct layer above the sand-sized particles. The sodium ions in the salt solution assist in settling the clay particles by causing partial flocculation. The test result is the volume of clay and silt particles in relation to the volume of the

sand particles.

In samples where there is a high volumetric proportion of clay and silt, or where the clay particles are active (i.e. have a high

cationic exchange capacity) clay and silt particles may remain visible, trapped within the sand particles at the end of the test.

In these instances. this standard test is not appropriate for the material in question, although the method provides some

suggestions for dealing with this situation.

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