Non-nuclear density testing

[mikeofBelAir]

If there is a thread on this, I apologize, but I couldn't find it.

I see there are a number of non-nuclear moisture-density devices now on the market. Does anyone have any hands-on experience they'd like to share? ( I am not talking Sand cones.....)
Most of the sales brochures stress the lack of nuclear regulatory oversight and the reduced cost because all that compliance with nuclear authorities is gone. OK, but I don't see where they trumpet the accuracy of their gauges. IMO, if the accuracy is suspicious, its a bad gauge/ procedure.

Yes, I'd like to do away with complying with nuclear regulators and all that cost, and employee training, but not at the cost of using a gauge that gives unreliable results.

Anyone have any experience?

 

[oldestguy]

You probably will get some comments from us real old guys. We started way before the nucs became popular. There may or may not be an ASTM test designation for these, but here goes.

The rubber balloon method has been around, but not very popular. However, the size of the balloon limited its usefulness. It was attached to a calibrated clear cylinder in which there is water. Calibrate it by setting it on a flat surface and reading the level. Dig a hole and then determine the volume of the hole by allowing the balloon to fill the hole and watch the readng of water level in the cylinder. Due to the limiting volume that can be measured, there was accuracy limitations. I think Soil Test in Chicago sold them.

The same thing can be done with other water measuring devices, such as a scale measuring weight differences.

In places where the "standard" ways won't work, such as coarse, gravelly soils, a large volume of hole is needed. Dig the hole and leave the sides undisturbed. Line the hole with a thin sheet of plastic, rubber, etc. Fill the depression with measured by weight or volume water, up flush with the original surface. This also can be done with calibrated sand where the hole volume required is far beyond the capability of the sand cone.

There used to be a method where a cylinder abut the size of a Proctor mold was driven into the soil and the weight collected in there was determine. Not sure how they allowed for the volume ofthe metal in the mold.

In clays the Shelby tube sampling technique could be a similar technique.

Anyhow, for years the sand-cone method was pretty standard until the nucs came along. Don't make the mistake of using too small a hole volume or errors will be large. The quart size jar and 4" cone is useless for most jobs.

 

[oldestguy]

A Google search brings up the rubber balloon method ASTM D-216. However, the hole size is 4 " and that is open to more errors than the larger holes as for Sand cone methods.

https://www.youtube.com/watch?v=IlF3m4OLFwc

 

[mikeofBelAir]

oldest guy,
Thanks for the response, but I am old enough to remember the balloon method--as well nukes that had to be hand calculated....
Trying to find a FAST, method that is non-nuclear.

 

[oldestguy]

Mike:

See if you can find a spec for a rapid test that the US Bureau of Reclamation used to have published in their Earth manual as method E-25. I never tried it,but using data from a compaction test you come up with a percent impaction right away. At least that saves some time.

While it may not have a "standard" by ASTM, a 1/2 inch rod about 30 inches long with a "T" handle works well for those experienced in the work of compaction control. It serves to do a number of things, such as mapping out where your test should be run to show averages or maybe worst areas. I've used it instead of density tests on simple jobs, by experience saying the bearing is OK for what is designed, etc.

 

[fattdad]

humbolt makes a resistivity device for such use. You have to develop the, "soil model" in the laboratory in advance of the field testing. Consider the "soil model" as a surrogate for a Proctor. Problem is when basing the density requirements on Proctor you can at least run a one-point confirmation if the materials change. The Humbolt device would be a challenge as on-the-fly soil models are not yet in general practice. Now if you are looking for non-nuclear methods and its for a manufactured subgrade material (dense-graded aggregate), one soil model may be appropriate. There is an ASTM (may be provisional) on this.

f-d

ípapß gordo ainÆt no madre flaca!

 

[BUGGAR]

I spent many hours in front of a camp stove in the Oakland hills waiting for soil samples to dry during field compaction tests. How can you not use this method?

 

[oldestguy]

OK one more. In the foundry industries they used a method to rapidly determine moisture content of foundry sand. That method along with the sand cone or rubber balloon is rather fast. The device may still be found out there. I used to have one but passed it on to those I mentored. It was called "Speedy Moisture Meter" , and it was an aluminum bottle shaped device with a pressure meter on its base. You dropped in a given weight of soil and then, from the cap a given weight of calcium carbide (as used in the old miner's lamps), plus two ball bearings. Clamp the lid on to seal it then and shook it up, running the ball bearings around to mix it up. Read the dial as the pressure builds up with the acetylene gas being created. Go to a chart and convert the pressure gauge to moisture content on a percent of dry density. The pressure gauge reads in moisture content on a wet weight basis. This could be done in abut a minute or two.

 

[oldestguy]

Do a search for it. I found one but was unable to copy and paste here for some reason.

 

[oldestguy]

This what it looks like.

https://www.google.com/search?q=spe...F5M%3A%3BRbP9uqQJTptTmM%3Bhttp%253A%252F%252F

http://www.labequipmentsmanufacture...ml;250;327&usg=__w8y0s38uloEKvbzLOWtEixR-buw=

 

[mikeofBelAir]

I appreciate the "old" methods, and have used most of them.
However, what i am looking for is some "high-tech" modern "gadget" alternatives to nuclear testing of moisture and density.

 

[BigH]

And, of course, we "all" believe in black boxes!

 

[mikeofBelAir]

Of course we do!
If it costs a lot of $$$ and LOOKS impressive, it must be right.
This is the one the salesman really liked!

 

[Ron]

Mike....several companies have tried resistivity methods over the years, but they haven't seemed to have caught on like the volumetric or nuclear methods. As F-D noted, Humboldt has one. I would imagine that it could be calibrate to the Proctor by taking measurements of the resistivity in the Proctor mold after compaction. They probably have a simple correlation method to use since if their correlation method were cumbersome, no one would use it.

Here's a link to Humboldt's device.....

http://www.humboldtmfg.com/edg/