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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
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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