SUPERPAVE Digest 27
Topics covered in this issue include:
34) Mat thickness & density
by Chris Blades <clblades@infoblvd.net>
87) Mat thickness & density
by "Ervin L. Dukatz, Jr" <104413.3167@compuserve.com>
90) RE: Mat thickness & density
by Jim Warren <acaf@nettally.com>
104) Re: Mat thickness
by Bvandre <Bvandre@aol.com>
106) Re: Mat thickness
by <DOR9009@VMHOST.CDP.STATE.NE.US>
107) Re: Mat thickness -Reply
by Maghsoud Tahmoressi <MTAHMOR@mailgw.dot.state.tx.us>
Date: Thu, 11 Sep 1997 08:07:23 -0400
From: Chris Blades <clblades@infoblvd.net>
To: superpave@mcfeeley.cc.utexas.edu
Subject: Mat thickness & density
Does anyone have any data on how mat thickness effects density with
superpave mixes of different sizes? What do different states use as
design criteria for mat thickness?
Thank You, Chris Blades
Date: Fri, 24 Oct 1997 14:06:54 -0400
From: "Ervin L. Dukatz, Jr" <104413.3167@compuserve.com>
To: "INTERNET:clblades@infoblvd.net" <clblades@infoblvd.net>,
"[unknown]" <superpave@mcfeeley.cc.utexas.edu>
Subject: Mat thickness & density
Florida DOT has reported that 4:1, thickness to max. size aggregate has
improved in-place densities. We have found testing Superpave, dense graded
and gap-graded mixes in our Troxler SSG that we get higher densities in the
normal size sample then when we compact the samples at design thickness of
2 inches.
Date: Mon, 27 Oct 1997 07:44:39 -0500
From: Jim Warren <acaf@nettally.com>
To: "'superpave@mcfeeley.cc.utexas.edu'"
<superpave@mcfeeley.cc.utexas.edu>
Subject: RE: Mat thickness & density
Referencing Dukatz work, We also have found much higher voids when using =
the SGC to compact samples at less than the typical 115 mm height. It =
is not linear, but voids tend to increase as compacted thickness =
decreases. Take one of your current SP mixes and compact at 115mm, =
75mm, 50mm and plot the results. You can compact thinner if you place an =
additional bottom plate in the base of your mold. The angle isn't =
exactly 1.25 I am told, but this is practical engineering, not rocket =
science. The aggregate tends to bridge at the thinner thicknesses and =
is one reason why Florida went to 4 times nominal.=20
Jim Warren
Asphalt Contractor Association of Florida, Inc.
Tallahassee, Florida
Voice: 850-222-7300 Fax: 850-942-5632 Email: acaf@nettally.com
-----Original Message----From:
Ervin L. Dukatz, Jr [SMTP:104413.3167@compuserve.com]
Sent:
Friday, October 24, 1997 2:07 PM
To:
INTERNET:clblades@infoblvd.net; [unknown]
Subject: Mat thickness & density
Forida DOT has reported that 4:1, thickness to max. size aggregate has =
improved in-place densities. We have found testing Superpave, dense =
graded and gap-graded mixes in our Troxler SSG that we get higher =
densities in the normal size sample then when we compact the samples at =
design thickness of 2 inches.
Date: Fri, 12 Dec 1997 06:12:33 EST
From: Bvandre <Bvandre@aol.com>
To: superpave@mcfeeley.cc.utexas.edu
Subject: Re: Mat thickness
This topic has been indirectly addressed before but I would appreciate
additional discussion.
Question: Do you have a policy regarding minimum allowable thickness of
Superpave mixes for maintenance use to respond to rutting or roughness?
What would be your maximum lift thickness allowed for asphalt layers not
subject to density (compaction) requirements? Would this change with traffic
volume?
What is the reasoning?
Thanks.
Bruce Vandre
UDOT Regional Pavement Management Engineer
bvandre@aol.com
Date: Fri, 12 Dec 1997 08:49:20 -0500
From: Chris Blades <clblades@infoblvd.net>
To: superpave@mcfeeley.cc.utexas.edu
Subject: Re: Mat thickness
Bvandre wrote:
>
> This topic has been indirectly addressed before but I would appreciate
> additional discussion.
>
> Question: Do you have a policy regarding minimum allowable thickness of
> Superpave mixes for maintenance use to respond to rutting or roughness?
>
> What would be your maximum lift thickness allowed for asphalt layers not
> subject to density (compaction) requirements? Would this change with traffic
> volume?
>
> What is the reasoning?
>
> Thanks.
>
> Bruce Vandre
> UDOT Regional Pavement Management Engineer
> bvandre@aol.com
New York State has has a construction item for "Truing & Leveling" that
is a varible depth leveling course of Superpave HMA that includes a
density monitoring compaction specification with no incentive or
disincentive. A project target density is established with a Nuc Gauge
and the density is monitored in relation to that.
All New York State Superpave mixes have a density monitoring
specification included. Some have incentive/disincentives and some are
just monitoring. The objective is (I Think)to make the contractor aware
that he must be concerned with density.
New York has just started to spec. superpave mixes for use in some
maintenance areas and it looks like most sections are 1.5" of 12.5 mm
superpave, sometimes on a variable depth T&L layer of 12.5 mm superpave.
Paul Mack (pmack@gwdot.state.ny.us) is a good contact for NYS info. Ron
Sines is the hands on guy for NYS.
Date: 12 Dec 1997 08:03:19 CST
From: <DOR9009@VMHOST.CDP.STATE.NE.US>
To: <superpave@mcfeeley.cc.utexas.edu>
Subject: Re: Mat thickness
I would suggest to OUR maintenance personnel to use only the 9.5 mm
nominal size mix. They will always try to feather it to "zero" no
matter what! Make sure they prepare the surface with a proper tack and
then hope it does the job. Defining minimum and what takes place are
two different things in a maintenance activity.
Second question??? If there is a situation where there is traffic BUT no
density requirement, I would not be concerned about lift thickness.
Without density requirements we've lost the battle. Really, without
density traffic will compact the top 4 inches no matter what the lift
thickness's are and what's left uncompacted will be subject to "the
elements".
Date: Fri, 12 Dec 1997 08:59:53 -0600
From: Maghsoud Tahmoressi <MTAHMOR@mailgw.dot.state.tx.us>
To: Bvandre@aol.com, superpave@mcfeeley.cc.utexas.edu
Subject: Re: Mat thickness -Reply
we don't have a set policy on min. thickness. Most our superpave mixes
have been 50mm thickness for 19mm nominal max size. Below 40mm,
we don't have density requirements other than requiring a rolling pattern
be established to achieve max compaction.
>>> Bvandre <Bvandre@aol.com> 12/12/97 05:12am >>>
This topic has been indirectly addressed before but I would appreciate
additional discussion.
Question: Do you have a policy regarding minimum allowable thickness of
Superpave mixes for maintenance use to respond to rutting or
roughness?
What would be your maximum lift thickness allowed for asphalt layers
not
subject to density (compaction) requirements? Would this change with
traffic
volume?
What is the reasoning?
Thanks.
Bruce Vandre
UDOT Regional Pavement Management Engineer
bvandre@aol.com