Topics Covered in This Issue Include s5

SUPERPAVE Digest 273

Topics covered in this issue include:

2) pavement density

by "Atenea Salomon" <>

3) Re: pavement density

4) Re: pavement density

5) RE: pavement density

by "McFarland, Sue" <>

6) RE: pavement density

7) RE: pavement density

by Matt Burke <>

8) Re: pavement density

by "Maghsoud Tahmoressi" <>

· To: <>

· Subject: pavement density

· From: "Atenea Salomon" <>

· Date: Mon, 15 Nov 1999 09:02:44 -0600

Hello everyone,

At the Minnesota DOT we are using AASHTO T-166 and T-245 for pavement density determination. Does anyone knows why the 2% moisture absorbed in the specimen is used as the parameter that differentiates both methods? Where should I look to find the creators of these methods?

What methods are your DOTs using for computing densities?

Thank you for all your help

Atenea Salomon

Assistant Bituminous Engineer

Mn/DOT

· To:

· Subject: Re: pavement density

· From:

· Date: Mon, 15 Nov 1999 11:52:57 EST

Dear collegues:

T-166 is simply asking a 2% precision. It says duplicate sp. gravity results

by the same operator should not be considered suspect they differ ny more

than 2%.

Am I on the same track, you have a question.

Chaudhry

· To:

· Subject: Re: pavement density

· From:

· Date: Mon, 15 Nov 1999 11:18:24 -0600

I don't see a relation to AASHTO T 245. We use the Hveem method here so AASHTO

T 245 would not be applicable. We use AASHTO T 166. While we do specify the 2%

limit and go with AASHTO T 275 in those cases, I am researching the use of an

Automatic Vacuum Sealing Apparatus. The parffin method is variable and too much

of a mess.

Kenneth Hobson

Bituminous Branch OKDOT

· To: "''" <>

· Subject: RE: pavement density

· From: "McFarland, Sue" <>

· Date: Mon, 15 Nov 1999 13:26:28 -0600

Ken:

What is an Automatic Vacuum Sealing Apparatus? I would love to get away

from the paraffin method, if possible.

Sue McFarland

Koch Pavement Solutions

Cold Mix Lab Manager

· To:

· Subject: RE: pavement density

· From:

· Date: Mon, 15 Nov 1999 14:17:26 -0600

The AVSA (Automatic Vacuum Sealing Apparatus) by Introtek uses the CoreLok

system for sealing the asphalt cores.

InstroTek, Inc.

3201 Wellington Court, Suite 101

Raleigh, NC 27615

919-875-8371

You can get it through Gilson at:

Gilson Company Inc.

PO Box 200

Lewis Center, OH 43035-0200

I ordered the 100mm and 150mm bags as well. The catalog numbers at Gilson are:

MS-90, MSA-10 and MSA-12.

Prices vary of course but you can expect to pay near $4000. The more bags you

buy the cheaper they are so they say. The InstroTek people do demos.

· To:

· Subject: RE: pavement density

· From: Matt Burke <>

· Date: Mon, 15 Nov 1999 14:17:01 -0800

We in the Las Vegas valley, have been using bulk specific gravities by Zinc Coating the specimens for a long time. They are more consistant in multi-lab situations and appear to be more representative of field conditions. While the use of zinc sterate was eliminated in the standards some time back, we have continued to specify this method.

One critical consideration for using the zinc was our coarse graded 3/4" HMA. These mixes "drain down" making measurement of SSD values inprecise. A comparison of our findings is given below:

SSD

Our lab shows the SSD value to be less than 2 percent. QC lab technicians with experience can vary "acceptable procedures" to produce test results between 1 and 7 percent. The end result is variability on the order of 3 to 4 percent.

Parrafin

Most QC labs can not stay consistent on this one, about 1 to 2 percent in-house. Temperature of the paraffin being the key. Overall variability multi-lab is 2 to 3 percent.

Zinc

Both tests led to high variability in the test results. With the use of zinc sterate we now only deal with variations of no more than 2%, and typically less than 1% multi-lab. When we vary more than 1% with a lab we "investigate procedures."

· To: <>

· Subject: Re: pavement density

· From: "Maghsoud Tahmoressi" <>

· Date: Mon, 15 Nov 1999 16:35:04 -0600

We have used the Vacuum Sealing apparatus that is manufactured by InstroTech. It does a great job.

SUPERPAVE Digest 274

Topics covered in this issue include:

1) RE: pavement density

by "Jim Warren" <>

2) RE: pavement density

by "Atenea Salomon" <>

· To: <>

· Subject: RE: pavement density

· From: "Jim Warren" <>

· Date: Tue, 16 Nov 1999 08:07:08 -0500

Maghsoud,

Please contact me off the list. Thanks

Jim Warren

· To: <>, <>

· Subject: RE: pavement density

· From: "Atenea Salomon" <>

· Date: Tue, 16 Nov 1999 08:49:02 -0600

Where do I find the Zinc Coating procedure for determining density??

Is this zinc sterate something like parafilm?

Atenea Salomon

Assistant Bituminous Engineer

Mn/DOT

SUPERPAVE Digest 275

Topics covered in this issue include:

3) Re: pavement density

· To:

· Subject: Re: pavement density

· From:

· Date: Wed, 17 Nov 1999 12:20:14 EST

Gilson Company Inc., supplies the CORELOK system , I am enclosing a copy of

catalog information.

]

Thank You

Jim Bibler

Gilson Company Inc.

800-444-1508, ext 173

CORELOK

ASTM D 2726, D 1188; AASHTO T 166, T 275

Recent design innovations in SMA and open graded asphalt mixes have resulted

in samples that will retain more than the allowable 2% water when immersed,

producing inaccurate and highly variable density and air void values. Present

methods, such as wax-dipping, wrapping in film or trimming, are labor

intensive and themselves produce a high degree of variability.

Corelok uses a sophisticated vacuum chamber and specially designed polymer

bags to automatically seal 4 in. (102 mm) or 6 in. (152 mm) diameter

laboratory compacted or drilled core samples in preparation for immersion

weighing. The unit can also be used when testing beam samples from various

wheel -tracking devices. The operator simply places the bagged sample into

the chamber and closes the domed, Plexiglas cover. The chamber is quickly

evacuated by the vacuum pump, and the bag is automatically sealed when the

proper vacuum level is obtained. The cover opens at completion of the

process, normally about 2 minutes.

Extensive comparison testing and statistical analyses reveal that samples of

all types of mix designs tested with Corelok had significantly lower

variabilities and values were considered to yield more accurate results than

samples sealed by more traditional methods. Measured precision is 0.002 g/cm3.

Puncture resistant bags have the correct amount of resiliency to closely

conform to surface irregularities. Nominal bag densities are predetermined at

the factory, assuring highly reproducible test results. Bag densities can

also be field checked using the standard aluminum reference sample provided.

Proper bag selection is important to the outcome of the test. Select MSA-12

Large Bags for testing 6 in. (152 mm) diameter cores and MSA-10 Small bags

for 4 in. (102 mm) samples.

Corelok is powered by a 1-1/4 hp rotary vacuum pump with a capacity of 29.95

in. Hg (1 Torr). Chamber size: 17x17x7" (432x432x 178 mm) WxDxH. Exterior

dimensions: 19x20x20" (483x508x508mm) WxDxH. Shipping data: 200lb (90kg), 6

Cu. ft.