Summary of 3rd Asphalt Shingles Recycling ForumAs of 12-18-2007
Alan Selner, Rieth-Riley Company 219-324-4794;
Working with IDEM, INDOT and local governments
Key steps to sourcing & sorting shingles
Plant modifications, input and product quality testing for shingle mixes
Joe Schroer, Missouri Department of Transportation (MoDOT) (handout) 573-526-4353;
R & D on tear-offs into HMA since 2003
Field and lab testing of tear-off RAS – derived HMA resulted in a proposed MoDOT specification in 2005 and revised specification to take effect in 2008 (see ):
Additional testing of the mixture will be required to determine what the actual result in the mixture will be. Until this testing is complete, PG 58-28 will be required in mixtures designed for PG 64-22 with less than 70 percent virgin binder.
Mixtures requiring a polymer modified binder may not use shingles due to a lack of information at this point.
Four contractors are currently using mixtures in the State of Missouri that include shingles from tear-offs or manufacturing waste. Almost 10,000 tons of shingles will have been used in HMA in Missouri in 2007.
For more general information about the MoDOT specification story, see:
- continued (Page 2 of same handout: “AASHTO Subcommittee on Materials”)
The AASHTO Subcommittee on Materials has two provisional methods for asphalt shingles in HMA: MP 15 – Standard Specification for Use of Reclaimed Asphalt Shingle as an Additive in Hot-Mix Asphalt and PP 53 – Standard Practice for Design Considerations When Using Reclaimed Asphalt Shingles in New Hot-Mix Asphalt.
These are currently being revised for nomenclature standardization and state-of-the-practice. The revisions are scheduled to be balloted in the Spring of 2008.
Changes under way for the 2008 construction season will allow increased use of RAS.
By using the 70 percent limit for virgin binder, mixtures may contain a higher amount of shingles without changing the grade of binder.
A standard gradation for shingle aggregates is included to reduce exposure of laboratory technicians to the high levels of dust after removal of the asphalt binder.
R. Christopher Williams, Iowa State University (handout) 515-294-4419;
Presented for Mihai Marasteanu, University of Minnesota (U of MN) 612-625-5558;
In reference to the presentation by Professor Marasteanu (based on a paper by Jim McGraw, et. al.) " at the annual Association of Asphalt Paving Technologists (AAPT) meeting in San Antonio, Texas, March 12 - 14, 2007.
U of MN, Dept. of Civil Engineering asphalt lab tests on HMA sample, gyratory “pucks” as provided by Bituminous Roadways, Inc. from the Dakota County / MOEA study (2005 – 2006):
20% reclaimed asphalt pavement (RAP),
15% RAP + 5% Tear-off recycled asphalt shingles (RAS), and
15% RAP + 5% Manufactured RAS.
(Note: All three mixtures contained the same virgin asphalt binder PG 58-28.)
Prepared by ShingleRecycling.org and DKAPage 4 of 11