Soils classification

[msharief]

I would like to know whether we need to run
D1140 (200 wash) when we are already doing
200 wash while we run the hydrometer(D422)
while we do soils classification.

Mohammed A Sharief

 

[Focht3]

Not as far as I'm concerned. I see no point in running a -200 on a separate sample; this could lead to confusion (due to sample variability.) Seems like an unnecessary step.

 

[Ashayeri]

select a repreasentive sample approximately 300 gr from your soil dry it in oven for 24 hour then weight it, then wash it from #200 put the remained in the oven for 24 hour and passed also. then seive the remained after 24 hour and use 50 gr of passed for hydrometer analysis. hydrometer analysis on the passed 200 is more trustable.

 

[Ron]

The purpose of ASTM D1140 is to quantify the fines, but not characterize them. It is a quick and inexpensive test as compared to the hydrometer portion of ASTM D422, which both quantifies and characterizes the soil specimen with respect to its particle size. If you are already doing D422, no reason to add D1140, but for multiple "check" tests, D1140 would be more expedient.

 

[msharief]

This is in response to Asheyari response
Whatever u suggested is against ASTM
procedures.The way u suggested is not
correct.D1140 uses hot oven and D422 air dry samples. Mohammed A Sharief

 

[Ashayeri]

dear msharief

D422 uses material passed #10 for hydrometer analysis and i am in the idea that hydrometer analysis in material passed #200 after doing D1140 is more repreasentive for the clay fraction(<0.002mm) of soil.

regards

 

[Focht3]

Run D422. The last step is to oven dry the soil in the hydrometer and weigh it - so you have an exact soil dry weight to use in calculating the hydrometer results.

Then run D1140 on the oven-dried &quot;remains&quot; of the D422; the results will be used on the same grain size curve (well, they should be, anyway.) This will give you a &quot;good&quot; point on your curve for comparison to the calculated hydrometer results. Remember that D422 has a lot of potential sources of error...

 

[bb29510]

The method we use is. Dry sample, 50-100 grams hyd, then wash 200 after hyd, dry sample, then mechanical gradation. all test was ran with same orignal sample of 50 -100 grams. Heavy clays close to 50, heavy sands close to 100 grams