Nuke Gauge Help

[Terminalshck]

The engineer comp. I am working for told me that my field numbers for in place density are incorrect for density.
My daily standard and moisture are
2300 and 629
12 inch depth
My max Dens is 110.0 @ 12% for the project.

Wet.D 124.9
Water content pcf 13.4
Dry D 111.5
Water content% 12.1
I did the math on the set of numbers and are correct.
My employer told me that third are not the numbers he looks at.
The comp. looks at D. Count, M count and the ratios.

How is the Density count and Moisture count are
Calculated from the set of numbers above?
Thank you for your time.

 

[Ron]

The counts are "gauge specific" and part of the gauge calibration. I think your company is working with bad info on their calculation procedure. I would suggest you do a direct volumetric correlation using either a sand cone or drive sleeve.

You don't give the gauge manufacturer, but it would be a good idea to contact them and let them teach you how the gauge works. It is microprocessor controlled, and is generally not calculable to back into the counts. The counts are just that...they are counts of radioactive emissions from the extended rod back to the counter. The density of the material through which the emissions pass is correlated to how many particles are absorbed, reflected or make it through to the counter.

 

[BigH]

Well, Ron is correct. Maybe your seniors are old foggies like me who had those ancient charts that told them the density count gave so much lb/f3 of wet soil and the moisture count told them how much was water so dry density would then be computed. But that was a long long time ago (1975 for me).

 

[Ron]

BigH....we are not old! Seasoned or experienced maybe........Old? Nope! Only oldestguy will admit that one!

And yes...I remember looking up the counts on a chart! 1977+ for me.

 

[emmgjld]

I never thought I would being able to top Ron or BigH.
I fondly remember the old charts, also trying to correct for not well understood chemical (gypsum was & is always fun). My memories go back to summer 1966, working for my father.
I wonder that anyone would insist on doing all the calcs. Too many opportunities for tech error. If I want to inspire tech error, I just insist on a sandcone. That can be a humbling experience for even the best.

 

[BigH]

@emmgjld - a humbling experience for even the best?? - and I agree! Here in Malaysia and also in India, at least 5 people carry out the sand cone! In Toronto, we used the MTO method - we had a "dip stick" that was calibrated for volume of hole and number of blows required (did you know that ASTM D 698 is calibrated to apply 2.34 kg-m/mm2 on each layer? I found that out today - but I digress. Anyway - we would use a rubber balloon method - dig the hole with the plate, then figure out the volume of the hole by the rubber balloon. then we would weight the material dug out, add a bit of moisture to it if our "experience" indicated it was a bit dry - or let it dry (our experience - as a youngun back then, the experience was a big little) - when just right, we would then compact the soil from the hole into std mould using the dipstick to tell us how many blows per layer based on the holes volume - then, comparing the two volumes to give the relative compaction - would take at least an hour for each test.

 

[Terminalshck]

Sorry it took so long to get back with you gents.
Troxler gauge 3440
Daily DSC 1909
Daily MSC 684
Max Dem. 100 PCF
Max Moist 10.2
12 inch depth

1-Density count 686
2-Moisture count 104
3-WD Pcf 103.8
4-Water Pcf 7.0
5-DD 96.7
6-%M 7.3
The engineer told me that base on the
Numbers in lines 3,4,5 and 6
I could not have got the numbers in lines 1 & 2
Is there a math formula I can do to check this or a form chart? If so please let me know
Thank you.

 

[Ron]

unless I'm completely missing something, you have no capability to manipulate or change the numbers in the gauge readout. Again, call Troxler and tell them your issue and get their take on it. You'll have a correct answer in a minute or two. Worth the call, since based on your description I doubt your boss's explanation.

 

[bb29510]

the way you do it is take the m count and dived by m standard. look that number up on chart, do the same with d count and d standard. subtract each and that dry density. you can do it with a calculator but you need more information that you did not provide