Hydrometer

[Jameschen6]

Hello everyone,

A couple of times my boss mentioned a simplified hydrometer method. He said the method I use is very old and costly. But I am sure the way is still in the standard. He can not remember the exact name (may have phrase overnight). I search internet and have nothing clue for such thing. Any idea?

 

[emmgjld]

Are you referring to the new ASTM Standard or the old, D422?
The older hydrometer test, as part of D422 is fairly simple and straight forward. Just requires a lot of attention to proper laboratory procedure. I have it performed for most classification tests. The test is being modified and may be a standard by now. The use of charts & simple calcs is a thing of the past. We are going to run the new & old methods w/calcs to compare what has really changed.

 

[Jameschen6]

I follow the Standard MTO LS 702 which I believe to be based on D422. Generally, (a) the soil need to be air dried, (b) at least 16 hours dispersion, (c) 1, 2, 5, 15,30, 60, 250 and 1440 minutes readings. These 3 steps are time consuming.(a) may be speeded up slightly by putting sample in low temperature oven. (c)250 minutes may be long enough to separate silt and clay for some kind of soil. It all depends. What is about (b)?

Do you mean that D422 have two parts. One is old and one is old. Honestly I have never read D422 thoroughly.