Nuclear Densometers analysing results? 2

[Cashwah]

A soil sample is tested using a Nuclear Densometer Test;
I have a Moisture standard of 650 and a Density standard of 3130.
I also have Test Results(in backscatter position)of Moisture content 130 and Density count 900.
How is the dry density and moisture content derived from this information?

 

[BigH]

Well, apparently you have an old machine(??) or don't have it set up for the on-board computer to do the calculations for you.

In the old days (quite old), we had tables - you would look up 130 on the moisture table and it told you the pcf of water you "have". Then you look up 900 on the backscatter table (there was a different table for backscatter, 2" probe depth, 4" probe depth, 6" probe depth and 8" probe depth). From the backscatter table you get the wet weight of the soil (pcf). Subtract the water pcf from the wet pcf to get dry unit weight. Compare to your Proctor value.

Oh, those were the days . . . . . . . . . . not.

 

[looksatstars]

Close BigH.
I must be really out of the times as those old densometer are the only kind i used.

You would take your moisture reading and divide it with your moisture standard of 650 and get the corresponding moisture ratio from the tables.
Then take your density reading and divide that from your density standard to get your density ratio.
dividing your moisture ratio from your density ratio will give you your moisture content.
Each set of tables are made for each model. I think these models are 15 years old. Troxler was a main manufacturer

 

[BigH]

You might have me there - I haven't used a nuke in a practicing sense since 1977 so, . . . If I am not mistaken, the tables I had were based on the "calibration" of the machine which was done every year so you read pcf of water and wet pcf of soil directly. But, as I get older, more fuzzy logic gets in the way.