SUPERPAVE Digest 273
Topics covered in this issue include:
2) pavement density
by "Atenea Salomon" <>
3) Re: pavement density
by
4) Re: pavement density
by
5) RE: pavement density
by "McFarland, Sue" <>
6) RE: pavement density
by
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
by
· 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.