What is this ... action to find ME not persuasive!?!
There's all kinds of excitement in the ASTM subcommittee on Pervious Concrete! Here it is: ASTM C 09 ballot 12-01 item 18 is "Action on Negative To Find Matthew Offenberg's Negative Not Persuasive on the C09 (05-11), Item 46, New Standard (WK29212) WK29212".
Please understand, I'm a huge supporter of this test method -- it's something the industry needs -- and Walt Flood IV has done a great job leading this task group up to this point. Specifications today reference ASTM C 140 which gives "density" but not voids. And I say "density" instead of calling it just density because it gives us a number that looks kind of like a density, but, we all agree, isn't the true mathematical density of the material. We need a test that measures the true density of pervious concrete, and this standard that was drafted is close to where we need to be.
For those of you following along in the text, it reads:
New Standard Test Method For Density and Void Content of Hardened Pervious Concrete (WK29212) on Ballot Ballot C09 (05-11) Item 046 {1}
blah blah blah{2}
Negative Voter: (Matthew Offenberg, W R Grace)
Negative Comment:The precision and bias statement was drafted based on insufficient data. The task group did a good job in testing different aggregates and placement techniques, but the P&B is only based on three tests. For this standard to be used for acceptance testing, there should be at least 3-5 more tests.
Non Persuasive Rationale:A motion was made and seconded to find it non-persuasive because the data generated by the task group exceeds the minimum ASTM requirement for precision statements which is one lab. The task group intends to run a full ILS within 5 years. During discussions it was mentioned that 2 round robins were conducted by the task group in the development of this test method. The first was based on cylinders made in the lab and included 6 labs. The second was based on cores cut from 3 different field placements. In addition the reference mentioned in the balloted draft standard includes cores cut from 2 placements and 1 set of cylinders placed in the laboratory.
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However, to clarify what this ballot means, the subcommittee needs to find me not persuasive so that the new test for hardened density and voids of pervious concrete field cores can be published. This is a BAD idea. On the previous ballot, I voted negative because with only 3 tests, we don't have a good feel for how accurate the test is and thus what kind of specification limits we can tie to it (for something like ACI 522.1). My goal was to have the task group provide us with a better feel for how tightly a designer can specify limits for density and voids and not cause either a dispute (because the limits are too tight and thus not achievable) or a project failure (because the specification limits are too loose and thus allow substandard material to remain in place). Even if this test isn't included in 522.1, or the UFGS for another 4 years, it will find its way into other project specifications and will cause problems if architects and engineers aren't provided with good guidance on setting acceptable ranges (like +/- 5 pcf or +/- 5% voids). Until we know what those ranges should be, and provide such guidance, it is irresponsible to publish this standard which is clearly written as an acceptance test.
This whole situation is a little weird. I've been in the position to have people voting for me, but never against me. So in this situation, a negative vote is a good thing, that's what I'm asking for. It's like a biopsy, a negative result is good. If you are an ASTM voter, please vote negative on C09(12-01) Item 18.
Flood IV, I encourage your response below.
{1} Editor's Note: The "Ballot Ballot" is the official wording, not mine.
{2} Editor's Note: The "blah blah blah" is my wording, not the official text. I've removed some web instructions.
