A number of shingle recycling research and development projects are underway. These, plus the many other private development efforts, speak to the need for continued communications and specification development at a national level.
The following are some of the past, current and future shingle recycling projects (in reverse chronological order)
AASHTO Shingles Recycling Specification
The American Association of State and Highway Transportation Officials (AASHTO) and its Subcommittee on Materials (SOM), are in the final stages of adopting a materials specification that itemizes specific quality assurance/quality control requirements for utilizing manufacturer and tear-off shingle scrap in hot mix asphalt (HMA).
Detailed requirements include:
· The final RAS product must be sized and screened such that 100 percent passes
the 0.5-inch sieve screen
· Maximum addition rate contractor option
· Gradation must meet the requirements of the mix design
· Deleterious material must not exceed a maximum of 0.5 percent by weight
cumulative total (i.e., combination of all: metal, glass, paper, rubber, wood, nails,
plastic, soil, brick, tars and other contaminating substances)
· Asbestos level established by the state or U.S. Environmental Protection Agency (EPA).
AASHTO is a nonprofit, nonpartisan association representing highway and transportation departments in the 50 states, the District of Columbia and Puerto Rico. Its primary goal is to foster the development, operation and maintenance of an integrated national transportation system.
At its last meeting on Aug. 10, 2005, in Santa Fe, N.M., the AASHTO SOM, and its Technical Section 2c (Asphalt-Aggregate Mixtures), decided to recommend the proposed recycled asphalt shingle product specification for full committee balloting. It is expected that the full committee will approve the subcommittee recommendation and this will be published as a new AASHTO specification in 2006.
For more information on the results of this AASHTO SOM meeting, or a copy of the draft shingle recycling specification, contact:
Thomas E. Baker, P.E. (AASHTO Subcommittee, Tech Section Chair)
State Materials Engineer, Washington State Department of Transportation (WSDOT)
State Materials Laboratory, Environmental and Engineering Programs
PO Box 47365
Olympia WA 98504-7365
Phone: 360-709-5401
Construction & Demolition Recycling magazine article
Many of the projects in this summary are mentioned in a recent article in Construction & Demolition Recycling Magazine (www.cdrecycler.com):
Construction & Demolition Recycling magazine July / August 2005 article: “Shingle – Minded Purpose” by Dan Krivit Shingle-Minded Purpose
EPA-Funded Project to Be Produced by CMRA
The primary goal of this new EPA project is to develop and demonstrate recommended best practices that provide for superior quality assurance/quality control (QA/QC) that can be utilized by profitable shingle recycling operators throughout the nation. The project has three principal objectives, according to the Construction Materials Recycling Association (CMRA):
· Demonstrate successful and appropriate environmental and worker health protection procedures
· Document materials engineering benefits and methods of QA/QC to optimize their pavement performance effects
· Develop operational guidelines that maximize cost-efficiency while attaining minimum environmental, worker health and safety, and engineering standards.
The project will be produced by CMRA with key partner support from a wide variety of public and private agencies and companies.
“This project will build directly on the substantial efforts of other research and development efforts such as the recent RMRC project #22 in order to help bring tear-off shingle recycling technology to full-scale implementation,” says William Turley, executive director of the CMRA.
For more information about the project, the CMRA can be contacted at (630) 585-7530 or at info@cdrecycling.org.
For more information, see:
Minnesota Lab Research on Tear-Off Shingle Scrap
The Minnesota Office of Environmental Assistance (OEA), via a time sensitive grant through Dan Krivit and Associates (DKA), is funding this Minnesota Lab Study Project. This OEA project directly complements a parallel study sponsored by the Missouri Department of Transportation (MoDOT). (See MoDOT project description below).
The goal of this OEA Project is to complete the testing of samples adequate to allow Minnesota Department of Transportation (Mn/DOT) to recommend changes to the State hot mix asphalt (HMA) pavement specifications that will allow the use of tear-off shingles in HMA as a normal business practice. The Minnesota OEA project has the following objectives:
· Develop a study methodology to compare the relative impacts of tear-off vs. manufacturer RAS on HMA quality and performance. This methodology should use standard practices and methods whenever possible such that the tests can be replicated by other research in the future.
· Measure total asphalt cement (AC) content (percent) and PG binder grade variability in tear-off shingle scrap compared to manufacturer shingle scrap and other control samples (i.e., Mn/DOT lab extraction and PG grading).
· Conduct a controlled set of HMA laboratory analysis to provide empirical data of tear-off vs. manufacturer shingles and other control samples on HMA strength (i.e., U of M indirect tensile tests).
· Conduct a controlled set of recycled asphalt shingles (RAS) analyses to develop standard practices and methods to measure relative amounts of deleterious materials in the ground/screened RAS product (before incorporating into HMA).
· Analyze the data results, and if these indicate that tear-offs are safe and feasible.
Missouri Lab Research on Tear-Off Shingle Scrap
The Missouri project will provide the necessary similar and additional lab data to further analyze the hot-mix asphalt (HMA) supplemented with recycled asphalt shingles (RAS) produced from tear-off shingle scrap. The RAS-derived HMA test samples will be compared to control samples of HMA produced from 20 percent RAP, 0 percent RAS mixes. The University of Minnesota, Department of Civil Engineering, is already scheduled to perform similar lab analysis using its equipment to measure indirect tensile strength for the Minnesota Department of Transportation.
The project will result in verification or modification of requirements within the new draft Missouri Department of Transportation (MoDOT) specification on tear-off shingle recycling into HMA. This project will conduct additional empirical lab tests needed by MoDOT engineers in order to confirm requirements within their new draft specification allowing recycled tear-off shingles in HMA.
This Missouri project directly complements the Minnesota lab project (see project description above).
For more information about the MoDOT specification, see
Missouri Takes Lead in Shingle Recycling
The Recycled Materials Resource Center (RMRC) funded a project produced principally by the Minnesota Department of Transportation (Mn/DOT). This RMRC Project, Overcoming the Barriers to Asphalt Shingle Recycling (RMRC Project 22), extends over 14 years of research and development in Minnesota and selected other states on recycling of shingle scrap. This RMRC Project focused on field-testing, market development, and technology transfer of tear-off shingle scrap recycling. The end-use road construction applications demonstrated included use of recycled asphalt shingles (RAS) as: (1) a dust control supplement; (2) an unbound aggregate supplement as base; and (3) a 5 percent blend into hot-mix asphalt (HMA). One of the first products was an “Environmental White Paper” documenting the results of a controlled personal air sampling of ambient dust generated from a shingle recycling operation. A major outreach strategy was the April 2003 Second Asphalt Shingles Recycling Forum held in Bloomington, Minn.
In the past, the additional quality assurance/quality control (QA/QC) challenges of residential tear-off shingle scrap have been barriers to development of this type of asphalt shingle scrap. In Minnesota, there is more demand for recycled manufacturer shingle scrap than available supply. Thus, there was a continued need to develop tear-off shingle recycling as addressed by this RMRC Project.
For more information, see;
Click here: RMRC Project 22 Final Report
RMRC Project No. 13 / No. 14: Specification
There was substantial recycled shingles specification development work recently completed by the RMRC. This other related project sponsored by RMRC was the “Development and Preparation of Specifications for Using Recycled Materials in Transportation Applications” (RMRC Project No. 13/No. 14). Conducted by Chesner Engineering, this related RMRC project resulted in the preparation of a draft shingle recycling specification submitted to the American Association of State Highway and Transportation Officials (AASHTO) for consideration and potential adoption. This RMRC Project No. 13/No. 14 resulted in recommendations currently being acted upon by the AASHTO’s Subcommittee on Materials (see AASHTO shingles recycling specification above for more information).
For more information:
Click here: Reclaimed Asphalt Shingles in Asphalt Concrete
SWMCB (Solid Waste Management Coordinating Board)
In 2004, the Solid Waste Management Coordinating Board (SWMCB) completed a two-year study and developed recommendations on how to increase the recycling of manufacturer shingle scrap in the SWMCB region. County engineers were involved in discussions about the appropriate role of counties in encouraging hot mixed asphalt (HMA) producers to use manufacturer shingle scrap in HMA used to pave county road construction projects. The project resulted in a web page on www.greenguardian.com to promote the recycling of manufacturer shingle scrap.
Since completing the project described above, the SWMCB has continued efforts to help expand the market for recyclable shingles. Ongoing SWMCB technical staff efforts include evaluation and promotion of proactive County procurement practices. Such practices recommended in the 2004 study include bid advisories and alternate bid language that indicates SWMCB Counties want to encourage highway paving bids that include hot-mix asphalt (HMA) with recycled shingle content. The SWMCB intends to continue with its market development efforts to promote use of tear-off (post-consumer) asphalt shingles and is a partnering organization in the new EPA funded project being produced by CMRA (see project description above).
For more information, click on the:
SWMCB’s Green Guardian – Shingle Recycling web page
There is a substantial amount of previous research and feasibility work (informally referred to as Phase One) conducted for Mn/DOT in the early 1990s. Within Phase One, a series of three studies were sponsored and published by Mn/DOT:
· Turgeon, Curtis M.,
· “Waste Tire & Shingle Scrap Bituminous Paving Test Sections On The Munger Recreational Trail Gateway Segment.” Office of Materials and Research, Minnesota Department of Transportation, February, 1991.
· Newcomb, David E., Mary Stroup-Gardiner, Brian M. Weikle, and Andrew Drescher, “Properties of Dense-graded and Stone-mastic Asphalt Mixtures Containing Roofing Shingles.” ASTM Special Publication 1193, ASTM, 1993
· Newcomb, David, et al., “Influence of Roofing Shingles on Asphalt Concrete Mixture Properties.” Report MN/RC-93/09, University of Minnesota, Minnesota, 1993.
Summary & Abstract
(http://www.moea.state.mn.us/lc/purchasing/newcomb-summary.pdf)
Full report
(http://www.mrr.dot.state.mn.us/research/MnROAD_Project/MnRoadOnlineReports/93-09.pdf)
· Janisch, D. W. and C.M. Turgeon, “Minnesota's experience using shingle scrap in bituminous pavements. Final report, 1991-1996.” Minnesota Department of Transportation, Maplewood, MN. Report No. PB-97-132278/XAB MN/PR--96/34, October 1996.
These earlier research and development projects led to the first version of the Mn/DOT materials specification in 1996 to allow up to 5 percent manufacturer scrap shingles in certain asphalt hot mixes.
The Phase Two Mn/DOT Project (approximately 1997 through 2002) was focused on outreach to expand implementation of manufacturer shingle scrap recycling. The top Phase Two priority was to increase utilization into HMA as per the current Mn/DOT specification.
A result of the Mn/DOT Phase Two Project was an information “tool kit.” Mn/DOT published this as, A Guide to the Use of Roofing Shingles in Road Construction: It’s All Part of the Mix and included the following fact sheets:
· Vendors of Shingle-grinding Equipment (updated by the SWMCB, February 2004)
The Minnesota Office of Environmental Assistance (OEA) helped further disseminate this shingles recycling Guide via the OEA Environmentally Preferable Purchasing web page,
www.moea.state.mn.us/lc/purchasing/shingles.cfm ,
with the subsequent links to view the individual fact sheets as listed (and hyperlinked) above.
This Guide packet was originally mailed out under signature of Patrick C. Hughes, Mn/DOT Office of Materials & Road Research, in September 2002 to local engineers, hot-mix asphalt producers, shingle manufacturers, solid waste / recycling officials, and other interested parties. It was subsequently used at related industry conferences, workshops and other forums.
CMRA Original Project: Shingle Recycling.org
The Construction Materials Recycling Association (CMRA) is the lead sponsor of the Asphalt Shingles Research Assessment Project (ASRAP) an ongoing, long-term development project to improve the market for asphalt shingles. Other co-sponsors include the University of Florida (Gainesville, Fla.), the National Roofing Contractors Association (NRCA), and U.S. EPA. (Region 5, Chicago, IL). The ASRAP project was initiated at the First Asphalt Shingles Recycling Forum held in Chicago in November 1999. The project began a survey of state agencies and private recyclers in 2001 and culminated in the publication of the
Web page www.ShingleRecycling.org a comprehensive clearinghouse of information on the subject. The 2001 survey identified individual state regulations, asbestos sampling data, and other research and development projects being conducted around the country.