recycling shingles since 1996 presentation at the march 16, 2005 conexpo-con/agg by dusty ordorff...
TRANSCRIPT
Recycling shingles since 1996
Presentation at the March 16, 2005
CONEXPO-CON/AGGBy 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 Year’s of Shingle Recycling Experience
• 1,000,000 tons of finished hot-mix asphalt produced with shingles added
• About $700,000 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
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:– Sella 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
• When selecting a virgin binder grade, adjust (1) temperature interval lower. I.E. PG 64-XX provide a PG 58-XX virgin binder. Blending chart and residual AC recovery PG testing should be performed.
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 new record in 2004
• Tear-offs
• Other applications (dust control, additive to aggregate base)
For more information, contact:
• Dusty Ordorff, Bituminous Roadways(612) [email protected]
• Dan Krivit(651) [email protected]