Recycling shingles since 1996

Presentation at the March 4, 2004 MAPAContractors’ Workshop

By Dusty Ordorff

Bituminous Roadways, Inc.

Bituminous Roadways, Inc• Asphalt paving contractor

• Founded in 1946

• Three permanent asphalt plants

• Serve the Minneapolis/St. Paul metro area

Eight Years of Shingle Recycling Experience

• 800,000 tons of finished hot-mix asphalt produced with shingles added

• About $500,000 in savings due to avoided raw material costs

History of BRI’s shingle recycling

1996• MNDOT specs first allow 5% ground shingles

(manufacturer’s scrap), with project engineer’s approval

• First contract with CertainTeed Corp. of Shakopee• Maxigrind and Finlay screen used for processing• First use of ground shingles in hot mix

1997

• First OEA market development grant

• Shredder, hammermill, and Powerscreen used for processing

• Maxigrind burns up

1998

Two Maxigrinds and Finlay screen used for processing

2000• Two Maxigrinds and trommel screen used

for processing

• A series of cold-mixed field tests for lightweight pavement:– 100% ground shingles – Ground shingles + crushed concrete mix – Ground shingles + RAP mix

2001• Second OEA market development grant• ‘The Beast’ grinder made by Bandit

Industries and trommel screen used for processing

• Field demonstration at SKB’s Rosemount landfill as dust control:– Ground shingle + RAP mix– Ground shingle + crushed concrete mix

2002

• Positive news media coverage for projects in Hennepin and Scott Counties

• Air testing performed to evaluate potential risk of asbestos. No risks detected due to dust or fiber

2003

• MNDOT changes the wording in their scrap shingle specification to be less restrictive (allow HMA producers discretion to use shingles)

2003: “Tear-Off” demonstration • In City of St. Paul

• 50 tons of ground, tear-off shingles in HMA

• Certified sourcing of residential roofing scrap from:– Sela Roofing (roofing contractor)– Armor Waste (hauling, sorting and transfer)

• Nails removed by magnet on “The Beast”

2003: “Tear-Off” demonstration (cont’d)

• Side-by-side installation:– 5% tear-off vs.– 5% manufactured shingle scrap

• No performance difference

• Tear-offs seem easier to grind, but requires additional effort to remove nails and staples

Current Mn/DOT Specification

• Shingles used must be scrap from shingle manufacturers only No tear-offs (yet).

• Sources must be certified

• Gradation of ground shingle scrap:– 100% passing the ¾” sieve, and– At least 95% passing the #4 sieve

• Maximum of 5% by weight allowed

Processing and Handling• Grinding has very high wear on equipment

• Low production at about 20 tons per hour

• Extended storage of ground shingles results in re-agglomeration (chunking)

• Grind during the paving season (just-in-time for HMA production)

Processing and Handling• Shingle scrap must be free from other debris to

protect grinder

• We grind to ½-inch minus gradation

• Water helps with cooling and controlling dust

• Shrouding equipment further helps with controlling dust

• Feed ground shingles into our asphalt plants through standard recycle bins

Economics• Goal:

The cost of processing = The disposal (tipping) fee

• Offer a savings to our mix production

Experience With Use of Ground Shingles

• Less than 50% of the asphalt in the shingles is effective in the mix

• Use of ground shingles has not been detrimental to quality Cannot yet prove that ground shingles offers improved quality to our mix

Specific Projects• France Avenue – Hennepin County

• County Road 42/83 – Scott County

• 19th Avenue No. – City of South St. Paul

• Highway 13 – Mn/DOT

• Various residential street reconstruction projects – City of St. Paul

The Future• Consider blending ground shingles with

sand or RAP for storage

• New wording in state specifications should allow for more use – set record in 2003

• Tear-offs

• Other applications (dust control, additive to aggregate base)

For more information, contact:

• Dusty Ordorff, Bituminous Roadways(612) 366-2765DustyO@bitroads.com

• Dan Krivit(6510 489-4990DKrivit@bitstream.net

Summary of Past Research

Mn/DOT & RMRC April 10, 2003 Forum:

www.projects.dot.state.mn.us/uofm/shingles