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Plasticity Index

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ASHEAR

ASHEAR

Civil/Environmental
Joined
Jan 16, 2002
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5
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US
What is the meaning of a Plasticity Index "NP-4" ?
 
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NP means non-plastic so I would interpret this as PI ranges from 0 - 4
 
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I'd interpret it to mean non plastic for the material smaller than the Number 4 sieve.
 
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I would agree with cvg, as long as they were talking about a range for a few samples.
 
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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!
 
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NP-4 IS HOW THE PLASTICITY INDEX IS REFERENCED IN THE USDA - NRCS ENGINEERING PROPERTIES REPORT FOR VARIOUS SOIL TYPES.
 
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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!
 
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