SUPERPAVE Digest 27
Topics covered in this issue include:
89) effective bitumen content
by Peter Kadar <>
91) RE: effective bitumen content
by Jim Warren <>
92) Re: effective bitumen content
by "Robert B. McGennis" <>
Date: Mon, 27 Oct 1997 23:42:00 +1100
From: Peter Kadar <>
To: "" <>
Subject: effective bitumen content
Dear Collegues,
The term binder content is used to indicate the effective or nominal binder content? Some contracts refer to this as nominal binder content, some others believe that it should refer to effective bitumen content. In case of absorptive aggregates the difference can be as much as one percent, so we talk about a lot of money...
Your thoughts or comments would be much appreciated.
Peter Kadar
Date: Mon, 27 Oct 1997 08:24:38 -0500
From: Jim Warren <>
To: "''"
<>
Subject: RE: effective bitumen content
Pete,
You are right, it can cause confusion. In Florida at least we use the =
term binder content to mean the total binder content. Effective AC =
content is called effective AC or binder. Typically it is spelled out =
to avoid confusion. When using RAP you also have to deal with "New" =
binder content versus residual as well. To be clear, spell out the term =
you are dealing with, cause it seems like everyone has a name for =
something, especially between states.
Just remember: If this business wasn't so confusing, all the consultants =
would have to get real jobs <G>.
Jim Warren
Asphalt Contractor Association of Florida, Inc.
Tallahassee, Florida
Voice: 850-222-7300 Fax: 850-942-5632 Email:
-----Original Message-----
From: Peter Kadar [SMTP:
Sent: Monday, October 27, 1997 7:42 AM
To:
Subject: effective bitumen content
Dear Collegues,
The term binder content is used to indicate the effective or nominal =
binder content? Some contracts refer to this as nominal binder content, =
some others believe that it should refer to effective bitumen content. =
In case of absorptive aggregates the difference can be as much as one =
percent, so we talk about a lot of money...
Your thoughts or comments would be much appreciated.
Peter Kadar
Date: Mon, 27 Oct 1997 08:38:37 -0600 (CST)
From: "Robert B. McGennis" <>
To:
Subject: Re: effective bitumen content
Hi all. Good morning from Austin.
Peter Kadir and Jim Warren are right about the confusion regarding the terms
surrounding bitumen content. In our Superpave classes, we use the following
approach.
We have started teaching the terms "total binder content," which means all
the binder in the mix. Then there is "absorbed binder content," which is
the binder absorbed by the aggregate, typically expressed as a percent by
mass of aggregate. It is calculated by knowing the bulk and effective
specific gravities of the aggregate and the specific gravity of the binder.
Lastly, there is the "effective binder content," which is determined by
subtracting the absorbed binder content, from the total binder content. The
confusing part of this last calculation is that you first have to convert
the absorbed asphalt binder content from a percent by mass of aggregate to a
percent by mass of total mix.
Anyway, that is what we do. There is a good presentation of these concepts
and calculations in the Asphalt Institute's manuals SP-2 and MS-2.
Bob
Robert B. McGennis
The University of Texas at Austin