Transcript Shingles Recycling in Minnesota: A Status Report and “How

Shingles Recycling:
Experiences in Other States
Western Central Wisconsin Recyclers’
Special Shingle Recycling Workshop
September 12, 2006
By Dan Krivit
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
Engineering Properties
Composition of Residential
Asphalt Shingles
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
• HMA [Most Proven]
• 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 Affecting
HMA 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
Engineering Performance
Disadvantages
• Hotter mix requirements
• Stiffer mix
• Possible contamination
(Justus, September 2004)
3-12
Asphalt Shingles in HMA
Missouri 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
Deleterious Material
•
•
•
•
•
•
Nails
Wood
Plastic
Cellophane
Paper
Fiber Board
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
• Lab data as presented
July 12, 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 conduct
indirect tensile strength tests
MN: Asphalt Content of RAS
Shingle Asphalt Content
50.0
%AC
40.0
Manufacture
Waste
30.0
20.0
Demcon TearOff
10.0
0.0
1 2 3 4 5 6 7 8 9 10
Sam ple
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
Stiffness [GPa]
10.0
8.2
8
5.0
4
5.5
2.7
0.2
0.5
0.2
0
0
-10
Temperature [oC]
-20
States Using RAS
(Justus, September 2004)
Other States’ Specifications
[and Experiences]
• Georgia
- Manufacturing and Post Consumer Shingle
- Mixing Permitted
-100% passing the ½ inch Sieve
- Maximum 5.0% RAS permitted
- Gradation - meet requirements of Mix Design
- No foreign material ( paper, roofing nails,
wood, and metal flashing)
- Free of Asbestos when tested with Polarized
Light Microscopy. Test every 1000 Tons
(Justus, September 2004)
• 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)
• New Jersey
–
–
–
–
Manufacturing Shingle Waste Only
100% passing the ¾ inch Sieve
Maximum of 5.0% RAS permitted
Gradation meet the requirements of the mix
design
– No limitations on deleterious materials or
asbestos
(Justus, September 2004)
• North Carolina
–
–
–
–
Manufacturing Shingle Waste Only
100% Passing the ½ inch Sieve
Maximum of 6.0% RAS permitted
Gradation meet the requirements of the mix
design
– No Limitations on the presence of deleterious
materials or asbestos
(Justus, September 2004)
Texas DOT
• Texas DOT- State Highway 31 Corsicana,
Navarro County – 1997
- 2 x 1,000 foot sections post consumer RAS
- 2 x 1,000 foot sections manufacturing RAS
- 2 x 4,000 foot sections Control Mixture
• The Mix Design required 5% Post Consumer RAS and
5% Manufacturing RAS
• All three Mixes required 5% Stripping Agent
(Justus, September 2004)
7-2
Texas DOT- Conclusions
• Shingle binder content does not relate to
reduced quantity of virgin binder
• Felt appeared to migrate to the surface
• Processed shingles (RAS) did not clump
• Post consumer shingle more difficult to
handle
(Justus, September 2004)
Texas DOT - Conclusions
• Smoothness, stability, moisture susceptibility,
creep indicated similar characteristics among
the three mixes.
• 1999 Falling Weight Deflectometer testing
showed performance agreement among the
three mixes.
• Visual evaluation shows no apparent distress in
any of the mixes.
(Justus, September 2004)
• Texas (old proposed specification):
– Both Manufacturing and Tear-Off Shingle Waste
permitted
– 100% passing the ½ inch Sieve
– Gradation meet the requirements of the mix design
– No Contamination - dirt or other objectionable
materials
– No harmful quantities of asbestos when tested
according to EPA guidelines
New TCEQ Memo
• March 20, 2006
• Manufacturers’ RAS in HMA approved *
• Tear-offs not approved depending on stack
testing results and subsequent review of
impacts
• * Must follow same procedures as RAP
into HMA
American Association of
State and Highway
Transportation Officials
(AASHT0)
Recycled asphalt shingles
specification and practice
was approved by the Subcommittee
on Materials (SOM) August 2005
Review of AASHTO Specification
Subcommittee on Materials (SOM)
•
•
•
•
Both manufacturers and tear-offs allowed
100% passing the ½ inch Sieve
Maximum addition rate contractor option
Gradation and volumetrics must meet the
requirements of the mix design
AASHTO Specification (continued)
• Addition rates (Section 7):
“If RAS binder if greater than 0.75 percent,
the virgin asphalt binder and RAS binder
combination shall be further evaluated to
ensure PG requirements”
AASHTO Specification (continued)
• Tear-off material composition (Section 5.2):
May only include: asphalt roll roofing, cap sheets, and
shingles (including underlayment).
May not include other roofing debris such as: coal tar
epoxy, rubber, or other undesirables [metal, plastic,
wood, glass]
List of Roofing Waste Items
Included for Recycling
“YES” (Include these items):
• Asphalt shingles
• Felt attached to shingles
List of Roofing Waste Items
Excluded for Recycling
“NO” (Do NOT include):
•
•
•
•
•
•
Wood
Metal flashings, gutters, etc
Nails (best effort)
Plastic wrap, buckets
Paper waste
No other garbage or trash
Lista de material para techos basura
artículo para reciclar:
Si (Incluya)
No / Ningun
(No incluya)
• Repias
• Madera
• Papel del fietro
• Metal: flashings, canales
• Clavos
• Plastico
• Basura de papel
• La otra basura
AASHTO Specification (continued)
• Asbestos levels:
“…shall be certified to be asbestos free.” (Section 5.2)
“(Tear-off shingles are) construction debris and various
state and local regulations may be applicable to its use.
The user of this specification is advised to contact state
and local transportation departments and
environmental agencies to determine what additional
requirements may be necessary.” (Note 2)
AASHTO Specification (continued)
• Deleterious material maximum limits (Section 8):
(material retained on the No. 4 sieve)
– Heavy fraction = 0.50%
– Lightweight fraction = 0.05%
Missouri Shingle Spec
• Extrinsic Material Allowance Raised
– 3.0% Total
– 1.5% Wood
Comprehensive
Quality Control Plan
 Quality control of supply
 Worker safety and health protection
 Final product quality, storage and handling
 Shingle recycling system design
 Final product sampling and lab testing
Mn/DOT Spec
• Maximum 5% manufacturers’ shingle
scrap in HMA
• Considered a type of RAP
Example:
5% shingles + 25% RAP = 30% max RAP
• QA/QC standards apply
(blending charts)
Asbestos Risk
• Incidence of asbestos is extremely low
• Average content was only:
– 0.02% in 1963
– 0.00016% in 1973
Source: NAHB, 1999
ASRAS Data
• Iowa (1,791 samples), no hits
• Maine (118 samples), no hits
• Mass:
– (2,288 composite samples) 11 hits < 1%
– (69 tarpaper samples) 2 < 5%
– (109 ground RAS samples) 2 < 1%
• Florida (287 samples), 2 hits > 1%
Source: Paul Ruesch, April 13, 2003.
ASRAS Data
(continued)
•
•
•
•
Missouri (6 samples), no hits
Hawaii (100 samples), 1 hit > 1%
Minnesota (156 samples), no hits
Minnesota (50 tarpaper), 1 hit @ 2% - 5%
We still want more data!
(for EPA / CMRA project.)
Original source: Paul Ruesch, April 13, 2003.
DKA / AES
Fiber Tests
As part of the RMRC Project:
Environmental Testing of Airborne Particles at
The Shingle Processing Plant
April 2003
Information Sources
Construction Materials
Recycling Association
(CMRA)
EPA Project
• CMRA web page
http://www.ShingleRecycling.org
William Turley, Executive Director
(630) 585-7530
[email protected]
• Dan Krivit and Associates
(651) 489 - 4990
[email protected]
Equipment Vendors
www.GreenGuardian.com/pdf/shingle_vendors.pdf
Summary
Current Trends and
Future Growth
• Virgin asphalt is expensive, tipping fees
are rising, improved economics
• Applications other than HMA are being
developed
• Use of post consumer shingle waste is
promising
National Asphalt Price Trend
Source: U.S. Dept. of Labor: Bureau of Labor Statistics
Shingles Recycling into HMA
is a Proven Technology
• History of experience:
– Private operators
– State engineers
– Environmental regulators
• Substantial body of literature
• High quality HMA can be maintained
Quality Control = Savings
• QA/QC critical
• Use in HMA can be very cost effective:
– Cheaper alternative to landfilling
– $0.50 to $3.30 per ton of HMA
Quality Specs:
Scrap Feedstock and
Final Products
• Free of debris / trash / foreign matter
• Tear-off scrap must be asphalt shingles
only
• No nails!
Certification and Inspection of
Shingle Supply
•
•
•
•
Clear written spec for acceptable material
Certify suppliers
State licensed asbestos inspectors
Visual screening of all shingle scrap
– Types of shingles
– I.d. non-shingle waste
– I.d., layers, composites, thickness, etc.
Source: Paul Ruesch, April 13, 2003.
Model Sampling Protocol
(if required)
• Specified sampling frequency of incoming
loads
• Sampling of recycled asphalt shingles
(ground / screened product)
• Willingness to certify quality of finished
products
Source: Paul Ruesch, April 13, 2003.
Proposed Tear-Off Supplier
Certification Form
“….. We …. certify that:
– All tear-off shingle scrap came from
residential buildings having four or fewer
dwelling units; and”
– These residential buildings are not “regulated
facilities” according to state and federal rules;
and”
– The material delivered consists of asphalt
shingles only and contains no known
hazardous material.”
Proposed Tear-Off Processor
Certification Form
“….. We …. certify that:
– All tear-off shingle scrap came from certified
suppliers only (see “Supplier Certification
forms); and”
– The final product contains no known
hazardous material.”
Recommendations
1. CONTINUE MARKET
DEVELOPMENT:
– Cities, counties and states should use
alternate bid language allowing shingles
– EPA / CMRA project in progress:
• Asbestos statistics
• Best practices guideline documents
• Implementation / Outreach
Recommendations
(Continued)
2. MANAGE the asbestos issue:
– Restrict supply to private, residential homes
only (per NESHAP)
– Tight supply specification
– Certify suppliers (e.g., roofing companies)
– Inspect each load (suggest becoming a
licensed inspector)
Recommendations
(Continued)
3. PROTECT employee health and safety:
–
–
–
–
–
Develop dust management program
Develop employee hazard prevention
Shroud grinder
Water scrap shingles
Provide accurate information as part of a full
employee education program
Recommendations
(Continued)
4. GUARANTEE YOUR PRODUCT
QUALITY:
–
–
–
–
–
Asbestos free
No nails (use multiple magnets)
½ - inch minus
Controlled mix ratios
Exceed State QA/QC procedures