SUPERPAVE Digest 362

SUPERPAVE Digest 362

Topics covered in this issue include:

1) Troxler vs. Pine

by Christopher Bacchi <>

2) Re: Troxler vs. Pine

3) Re: Troxler vs. Pine

4) Re: Troxler vs. Pine

by Christopher Bacchi <>

5) Re: Troxler vs. Pine

by Christopher Bacchi <>

6) Re: Troxler vs. Pine

by "Ervin Dukatz" <>

7) Re: Troxler vs. Pine

by Christopher Bacchi <>

9) Re: Troxler vs. Pine

10) Re: Troxler vs. Pine

11) Re: Troxler vs. Pine

by Yetkin Yildirim <>

12) Re: Troxler vs. Pine

by "Ervin Dukatz" <>

To: "" <
Subject: Troxler vs. Pine
From: Christopher Bacchi <
Date: Wed, 07 Jun 2000 08:02:43 -0400

A while back, there was a paper done on a comparison between the

Troxler Gyratory compactor and the Pine Gyratory compactor. I

remember reading this paper, but do not recall who wrote it. Does

anyone know where I can get a copy of this paper?

Thanks

Chris

To:
Subject: Re: Troxler vs. Pine
From:
Date: Wed, 7 Jun 2000 07:40:07 -0500

I'm aware of a couple studies in the past year or two. One by the Missouri

DOT and another by Pine Instruments. I know Missouri DOT were finding

different compactive efforts with different SGC. In NE we are experiencing

the same situation that Missouri had. The only Pine we have in NE is

compacting to a greater density than any of our Troxlers. The other brands

of compactors are comparing very well.

To:
Subject: Re: Troxler vs. Pine
From:
Date: Wed, 7 Jun 2000 07:33:00 -0500

Do you mean the one at

or the one in the AAPT Journal? The AAPT web site is

Kenneth Hobson

Bituminous Branch OK DOT

405-522-4918

405-522-0552 fax

To:
Subject: Re: Troxler vs. Pine
From: Christopher Bacchi <
Date: Wed, 07 Jun 2000 08:53:46 -0400

That is the same problem we are having, the Pine is compacting to a greater

density. We are trying to come up with a kind of correction factor for the two.

Thanks

To:
Subject: Re: Troxler vs. Pine
From: Christopher Bacchi <
Date: Wed, 07 Jun 2000 08:58:50 -0400

I was referring to the Missouri paper.

To: <
Subject: Re: Troxler vs. Pine
From: "Ervin Dukatz" <
Date: Wed, 07 Jun 2000 08:36:18 -0500

How old are your SGCs'? We are using 5 baby Troxlers, 2 baby Pines, 2 big Pines and one Instron in four different states (WI, MN, IA and MI) without problems. The couple of time that we have had a correlation problem, it has been with reheated vs hot samples, ovens at different temperatures or samples with a different gradation.

Erv Dukatz

Mathy Construction Co.

To:
Subject: Re: Troxler vs. Pine
From: Christopher Bacchi <
Date: Wed, 07 Jun 2000 09:55:39 -0400

We have some of the original big 4140 Troxlers that are about 3+ years old. I believe the contractors have the baby Pines where this problem is occurring (3 different location). We are looking at the reheated vs. hot samples right now, and hopefully this will give us some explanation. Do you think the age of the Troxlers could have

something to do with it?

To:
Subject: Re: Troxler vs. Pine
From:
Date: Wed, 7 Jun 2000 09:23:12 -0500

We have been having some long discussions about "correction factors" here

in NE and decided that we don't want to go down that road. If we would set

a correction factor for one model others will soon demand the same whenever

there test results, if corrected, would be to their benefit.

Our position at this time is to require every contractor to meet the

Superpave specifications during their design and their QC on the project

with their gyratory. The contractor who's unit compacts to a greater

density will in turn require the use of higher quality aggregates, and that

relates to $$.

Also, we feel the resulting slight decrease in binder content can be

tolerated.

To:
Subject: Re: Troxler vs. Pine
From:
Date: Wed, 7 Jun 2000 10:23:32 -0500

We use an annual proficiency program to calibrate all of the SGC's. We've been

doing this for some time now with our Texas Gyratory Compactors. Calibration is

critical to get the Contractor Labs and State Labs on the same footing. So, the

differences between compactors are minor.

As discussed many times, there are significant differences between fresh plant

mixtures and reheated mixtures. To my way of thinking, the QC specimens are for

control and the QA specimens are for assurance. One gets into trouble though

when the QC specimens are used for QA if one doesn't understand the reheating

concept.

Kenneth Hobson

Bituminous Branch OK DOT

405-522-4918

405-522-0552 fax

To: "" <
Subject: Re: Troxler vs. Pine
From: Yetkin Yildirim <
Date: Wed, 7 Jun 2000 14:42:48 -0500 (CDT)

We did a very extensive study about comparison of SGCs. This

study was published at TRB 2000. We compared Rainhart, Test Quip, Troxler

Model No. 4141, Pine Model AFG1A, Interlaken, Pine Model AFGC125X and

Troxler Model No. 4140 SGCs. It was found that all seven compactors would

provide the similar results. You should be aware that comparability of

results is considerably influenced by many factors. Operator proficiency,

oven size and quality, compactor operating condition, adherence to

standard test procedures, and of course, material variability are among

the many factors that can influence the comparability of the compactors.

Yetkin Yildirim

512-232-1845

The University of Texas at Austin

To: <
Subject: Re: Troxler vs. Pine
From: "Ervin Dukatz" <
Date: Wed, 07 Jun 2000 14:49:38 -0500

Yes, I believe there some changes made to the devices to take out an intital precompaction that occured with the original devices. Erv

SUPERPAVE Digest 363

Topics covered in this issue include:

3) Re: Troxler vs. Pine

by Christopher Bacchi <>

To:
Subject: Re: Troxler vs. Pine
From: Christopher Bacchi <
Date: Thu, 08 Jun 2000 08:00:14 -0400

I believe that our QMS program helps to eliminate these variables you mention,

but we have tried to eliminate these variables by repeating tests, and

checking procedures and materials, but this does not seem to be solving our

problem. I feel that the 2 compactors perform differently, which is going to

cause very large headaches for the NCDOT, and I do not think I am alone.

SUPERPAVE Digest 364

Topics covered in this issue include:

2) RE: Troxler vs. Pine

by "Blankenship, Phil" <>

To:
Subject: RE: Troxler vs. Pine
From: "Blankenship, Phil" <
Date: Fri, 9 Jun 2000 23:01:27 -0500

Some great discussion on this topic. Yes there have been differences even

when the same operator within one lab is used. The region for error is

usually the angle check. It has always been my understanding since 1994 and

what we learned during the SHRP development that the angle should always be

check under the load. Check with your manufacture on this.

Even then there are differences. First, is everyone using the same type of

mixing? (Bucket mixer or Hobart mixer?) Ask those types of questions.

Keep in mind that the Superpave Gyratory error is still much better than the

Marshall differences in most cases. We could not even calibrate Marshall

Hammers. So we are getting better.

Finally, I always recommend that the design be verified via the DOT using

the same brand compactor that will be used in the design and on jobsite when

possible. This eliminates compactor differences that will affect the pay

factors.