D75 - Aggregate Sampling from Roadway

[DDBPE]

I had previously posted in the Civil/Environmental Forum an issue in regards to P-209 gradation after compaction. At the plant the average #200 was 6.8% and the after compaction tests were 12.5%

Now the supplier of the material is disputing the penalty along with us imposed by the owner (the #200 sieve was out of gradation on average 1.7% - finer) based on the sampling method.

The test method is ASTM D-75 (Sampling Aggregates from Roadway).
In the ASTM, it says to random sample (D3665), from these random areas take 3 equal samples and combine to form a field sample.
What was done in the field was not as the ASTM indicates. The area was divided into 12 equal sections, from each section - a backhoe was used to dig out a sample (this was P-209 compacted to 100% density). The sample was then pulled out of the pile.

We think we have a pretty good case in regards to the sampling method which should invalidate the test, therefore, the owner has no valid test data to impart a penalty.

I am looking for any thoughts or suggested back-up information I can use to show this, other than the ASTM (studies or something else).
Also, any articles on dense graded aggregates breaking down during compaction would also help.

Thanks in advance.

 

[fattdad]

was D75 the specified sampling method in the contract?

I hate this sort of defense. Is the material out of specification? I mean is it truely out of spec? From the original post, it may or may not be. . . The test results are disputed by virtue of the sampling method. It seems to me if you have 12 plots, 12 samples and 12 results all showing some level of concern, there's a materials problem. Would your confidence at this point be increased if the confirmation program returned to the field and took these composite samples?

f-d

¡papá gordo ain’t no madre flaca!

 

[DDBPE]

yes D75 was specified.

The plant results indicated all within the aggregate mix design (25 tests) and on the lower end of the range on the #200. The QA test was after placement and compaction (12 test), 11 of 12 test failed #200.

Also, no chance to go back and take samples. This penalty has come back to us after almost a year. A month after the placement, the runway was opened with 14 inches of asphalt on top. We were initially told everything was acceptable.

 

[EITGeotechnical]

The material passing the #200 will always be more if you taking the material after compaction. The plant and QA should take the sample at the same time and same location. The material need to meet the conveyor belt and if so it does not mean that material will meet the spec. after transportation. Usually the 5 rolling average should not be more than 5% higher/lower than the limit.

What will be the performance effect with the material higher than the limit on #200? what is the limits on #200?

 

[DDBPE]

EIT, the range for the #200 is 5-11. Our average was 12.7%.

 

[dik]

Not a geotekkie... but, some rambling thoughts...

I would think that the fines after compaction would not be significantly higher than the original material... else the material is too friable.

Is the material placed from the same as supplied to the site. It's possible to have large variations at a plant depending on where the material comes from the 'heap', unless the material is 'blended'.

12% passing 200 is too much and may lead to frost heave depending on the local.

Dik