Base coarse layer

[Mohammad Mashal]

Hello
I need to know if i take a Qc sample of base coarse layer after compacted to do tests on it ( sieve analysis, proctor, cbr, plastic index, losangeles,....etc).
The question
Is the gradation of the sample will change after compacted ?? Or just passing sieve 200 will increase??
Can i make full gradation to the sample or just passing sieve 200 ??

 

[MTNClimber]

It would depend on the strength of the individual particles. If the compaction equipment is able to pulverize the sample, breaking down the sand and gravel into smaller pieces, then the gradation will change. That's why a geotechnical engineer should approve the material prior to use.

 

[oldestguy]

Routinely in my experience all these tests are done before the stockpile is oK'd for use. Taking a sample after it is compacted and doing the tests is not common. If it is broken down some and fails some tests, I'd expect an argument from a contractor about this delay in testing until after the job is done.

 

[EireChch]

Ideally you would take a sample from the material in its loose condition. However, only the other day we took samples from a compacted fill as part of a forensic assessment.

 

[fattdad]

If it's some igneous rock source for the aggregate, I doubt there'd be much to worry about.

I'm working on a project where we'll be using foamed glass aggregate (settlement issue - need to reduce the embankment load). That stuff does break down - it's a part of its use!

f-d

ípapß gordo ainÆt no madre flaca!

 

[Mohammad Mashal]

Material is already approved from the consultant, they made all tests on it before it use.
I am a third party in the project, i am doing an inspection on construction materials, so i got a sample of base coarse after compacted.
Note: you can take a sample after compacted but you have to increase the passing sieve 200 percentage +3% , it noted in special specifications astm D75 .
I think (Los angles abrasion test) less than 40% it’s an indication that the breakage factor is few after compacted in my opinion.
So when we make full gradation, the percentage will not difference too much and will stays in the range.