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Shingles Recycling: Quality Assurance / Quality Control. A Presentation at the Sacramento RMRC Workshop on Tuesday, April 11, 2006 Presenter: Dan Krivit Dan Krivit and Associates. Recycled Materials Resource Center. www.rmrc.unh.edu. Presentation Outline.
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Shingles Recycling:Quality Assurance / Quality Control A Presentation at theSacramento RMRC Workshop on Tuesday, April 11, 2006 Presenter: Dan KrivitDan Krivit and Associates
Recycled MaterialsResource Center www.rmrc.unh.edu
Presentation Outline [Modified from presentation already in your big books! Make sure to get all additional inserts: • AASHTO spec • Bibliography • SWMCB packet
Definitions • Manufacturers’ Asphalt Shingle Scrap • Tear-Off Asphalt Shingle Scrap • Recycled Asphalt Shingles (RAS)(Crushed & screened)
History • 15 years + • Multiple research studies in lab and field • Manufacturer shingle scrap in hot-mix asphalt best known, most accepted practice • Still relatively new application
Recent Composition Weight Ranges of Typical Asphalt Shingles • 32 to 42% Coating filler (limestone or fly ash) • 28 to 42% Granules (painted rocks & coal slag) • 16 to 25% Asphalt • 3 to 6% Back dust (limestone or silica sand) • 2 to 15% Mat (fiberglass, paper, cotton rags) • 0.2 to 2% Adhesives (modified asphalt based)
Multiple Applications [Most Proven] • HMA • Aggregate (gravel) • Dust control • Cold patch • Ground cover • Fuel • New shingles
Factors Affecting HMA Performance • Aggregate gradation of RAS • Properties of final blended binder content within the HMA as affected by: • RAS asphalt binder • Virgin binder
Factors AffectingHMA Performance(continued) • Location RAS is incorporated into HMA • Temperature • Moisture content of RAS and other aggregates • Retention time in HMA drum
Engineering Performance Advantages • Reduce need for virgin binder • Add fibrous reinforcement • Modify PG grade binder High temp performance • Reduce landfill needs 3-11
Potential Benefits *(* Manufacturers’ RAS) • Cracking resistance • Rutting resistance • Conservation of landfill space Source: Paul Lum, Lafarge Construction Materials Ltd., April 13, 2003.
Challenges • Need for improved grinding and handling • Blending and storage • Continued research into engineering effects of RAP and RAS on AC binder content • Quality control and quality assurance
BarrierstoShingleRecycling • Economic reasons • Policy and regulatory compliance • Environmental concerns • Technical reasons • Public sentiment ----------- (Note: These barriers may be real or perceived!)
Engineering Performance Disadvantages • Hotter mix requirements • Stiffer mix • Possible contamination (Justus, September 2004) 3-12
Asphalt Shingles in HMAMissouri DOT Experience Joe Schroer, PE Construction and Materials Division March 30, 2005
In The Beginning • Approached by Pace Construction and Peerless Landfill • MoDOT Not Using RAP in Mixtures • Deleterious Material • Stiffness of Asphalt in Shingles
Why Should We Pursue Shingles? • High Asphalt Content • Granules Are Hard and Durable • Recycling CO$T
Concerns • How Will Deleterious Material Affect the Mixture • Can the Low Temperature Grading be Maintained at Various Blending Ratios
Asphalt After Blending with Shingle Asphalt • Resist Rutting • Resist Fatigue Cracking • Resist Cold-Weather Cracking
Asphalt Grades • High Temperature for Rut Resistance • Low Temperature for Fatigue and Cold Weather Performance Performance Graded = PG PG 64-22 (PG Sixty-four Minus Twenty-two) High Temp 64°C (147°F) Low Temp –22°C (-8°F)
Asphalt Modifications Require PG 64-22 • Stiffer at High Temperature – OK • Stiffer at Low Temperature • Use Lower Percentage of Shingles • Use Softer Roadway Asphalt
Deleterious Evaluation • Specification for Aggregate • 0.5% “Other Foreign Material” • Sticks, mud balls, deer fur, etc. • Shingle “OFM” • Approximately 3% Total
Nails Wood Plastic Cellophane Paper Fiber Board Deleterious Material
No Difference • Visually • Standard Mixture Tests • Placement
Can Tear-Off Shingles be Used? • Allowance in OFM Due to Small Percentage of Shingles and Trial Mixture • Start with Softer Roadway Asphalt
Where Are We?The “Ex” Factor 2 • Extrinsic Material Allowance Raised • 3.0% Total • 1.5% Wood • Expect PG 64-22 met w/ PG 58-28 • Extra grades optional w/ testing • Examining various proportions and asphalts • Exuberant Contractors
U of M Lab Data:Missouri Samples • Prof. Mihai Marasteanu,U of M Dept. of Civil Engineering • Preliminary results as of 4-6-2006 • Report with Mn/DOT lab data to be released soon
Mn/DOT lab data • Jim McGraw, Director of Mn/DOT’s Chemical Lab, Maplewood, MN • Preliminary lab data as of Thursday, April 6, 2006 • Report with U of M lab data, including Mo/DOT samples, to be released soon
New Minnesota Lab Study • Funded by OEA • Co-sponsored by Mn/DOT • Comparing manufacturer RAS to Tear-Off RAS • Mn/DOT to conduct PG extractions • U of M Civil Engineering to conductindirect tensile strength tests
U of M Lab Data:Minnesota Samples • Prof. Mihai Marasteanu,U of M Dept. of Civil Engineering • Preliminary results as of Thursday, April 6, 2006 • Report with Mn/DOT lab data to be released soon
MN: Mix Stiffness [GPa] @ 100 sec. 16 13.5 20% RAP 15% RAP + 5% Tear-off 12 15% RAP + 5% Manufactured 10.0 8.2 8 Stiffness [GPa] 5.5 5.0 4 2.7 0.5 0.2 0.2 0 0 -10 -20 o Temperature [ C]
Western States • California • Montana • Texas • Oregon
Minnesota • Manufacturing Shingle Waste Only • 100% passing the ½ inch Sieve • Maximum of 5.0% RAS permitted • Gradation meet the requirements of the mix design • Performance grade of virgin asphalt binder based on the properties of the shingle asphalt binder • No limits on deleterious materials or asbestos (Justus, September 2004)