ASTM Specification on Grain Size Analysis for Gravel and Cobbles

[Robert168]

Dear Members,

Does anyone of you know whether there is a ASTM specification on the grain size analysis for gravel and cobbles with a max. size of up to 200 or 250mm regarding testing procedures.

Thanks in advance.

 

[drfefefe]

Boulders >12"
Cobbles Pass 12" and retained in 3"
Gravel Pass 3" and retained in # 4 sieve (4.74mm)

 

[Robert168]

Thank you very much for your reply. In perticular, I would like to know the size of the sample to be taken for gradation analysis.

 

[iandig]

I think this very much depends on the standard you are testing to, from BS 1377-2: 1990, it requires a sample portion of approk 1000kg!!. I refer to this as you have given the dimensions in mm and not inch's. There are new European standards for gradings out now which EN 933-? from memory, and these may well have different min. masses for testing.
As a simple rule of thumb which I have always found useful, as a rough guide the nominal size in mm = the mass in kg, i.e. 200mm = 200kg, with the nominal size being where more than 10% is retained. This works really well upto nominal sizes of about 100mm, there after you are looking for a sample size in excess of 500kg from the guidance given in the BS.
As a material with a nominal size greater than 63mm, then it should be classed as an aggregate, hence the new EN for the testing of the grading, but like I said I am not sure what the new EN calls for.