Plasticity Index

[ASHEAR]

What is the meaning of a Plasticity Index "NP-4" ?

 

[cvg]

NP means non-plastic so I would interpret this as PI ranges from 0 - 4

 

[oldestguy]

I'd interpret it to mean non plastic for the material smaller than the Number 4 sieve.

 

[jgailla]

Plus one for cvg's response.

 

[TDAA]

I would agree with cvg, as long as they were talking about a range for a few samples.

 

[fattdad]

plasticity index, by definition is performed on the minus 40 sieve material. The lab is required to report NP if the sample is non-plastic. The ASTM does not acknowledge some range, like non-plastic to 4 as a range. Not saying that wasn't the lab's intent, it's just not a standard reporting method.

I'd ask the lab. You have no idea how few folks actually read the ASTM methods for how to run the tests and what/how to report the test results.

f-d

¡papá gordo ain’t no madre flaca!

 

[ASHEAR]

NP-4 IS HOW THE PLASTICITY INDEX IS REFERENCED IN THE USDA - NRCS ENGINEERING PROPERTIES REPORT FOR VARIOUS SOIL TYPES.

 

[fattdad]

I WAS ASSUMING THE LAB WORK WAS DONE USING ASTM STANDARDS. YOUR ORIGINAL POST WAS NOT CLEAR THAT THE TESTING WAS PERFORMED USING USDA-NRCS STANDARDS, WHICH I HAVE NEVER EVEN SEEN (BEING AN ENGINEER AND SUCH).

F-D

¡papá gordo ain’t no madre flaca!