astm d6938 nuclear density testing

[BigH]

I do not have access to ASTM D6938. Years ago, I remember that if one is using the troxler in a coarse soil (I am talking about 70% greater than #200 sieve, that one would take three readings with the nuclear guage but rotating the machine around the inserted rod by 120 deg - so that 3 readings are taken. This was to check if coarse material was causing some issues.

Can someone confirm or advise?

Cheers

 

[geotechguy1]

Sorry I'm not familiar with the ASTM standard. But when I was trained on a Troxler the two main things they wanted me to do were rotate 120 degrees and take 3 readings, and also pay alot of attention to how level the surface was and level the surface with sand if necessary.

 

[emmgjld]

The only mention in D6938 for rotating the gauge over an area is in the Oversize correction section, 10.6.1 .
I tend to remember this rotation around the probe hole was in the Troxler directions, although so much of my testing concentrated on just getting a good surface for 1 test, which can be quite a chore in itself.
As I am an old Campbell Guy, I am not that familiar with the Troxler of days past.

Now, in my dotage, I have gotten rid of my nuc. license (good riddance), my almost as old partner & I have purchased the Model 4590 Density Gauge from Troxler. The rotating the gauge 120 degrees is in the directions however, the preparation of a test surface that big is daunting, especially if dealing with oversized.

 

[BigH]

Thanks mates . . . as emmgjld said, it was my understanding on oversize to rotate 3 times . . . agree that ASTM says only 180 degrees.

Appreciate your thoughts.