Shingles Recycling: Quality Assurance / Quality Control
description
Transcript of Shingles Recycling: Quality Assurance / Quality Control
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
Material Introduction
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)
Applications and Performance
Multiple Applications
• HMA• Aggregate (gravel)
• Dust control• Cold patch
• Ground cover• Fuel
• New shingles
[Most Proven]
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
Barriers to Shingle Recycling• 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
3-12
(Justus, September 2004)
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
• RecyclingCO$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 PerformancePerformance 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
10.8 12.0
19.5
9.5
34.4 34.7
0
10
20
30
40
-10C -20C -30C
Stif
fnes
s @
100
sec
20% RAPPG 64-22
15% RAP5% shing.PG 64-22
MO: Mix Stiffness @ 100sec. (PG 64-22)
6.1
11.5
17.3
8.1
16.6
21.4
0
10
20
30
-10C -20C -30C
Stif
fnes
s @
100
sec
20% RAPPG 58-28
15% RAP5% shing.PG 58-28
MO: Mix Stiffness @ 100sec. (PG 58-28)
4.0
7.8
15.3
5.7
12.9
15.9
0
10
20
30
-10C -20C -30C
Stif
fnes
s @
500
sec
20% RAPPG 58-28
15% RAP5% sh ing.PG 58-28
MO: Mix Stiffness @ 500sec. (PG 58-28)
4.54.9
3.94.3 4.2
4.7
0
3
6
-10C -20C -30C
Te
nsile
Str
eng
th [
MP
a]
20% RAPPG 64-22
15% RAP5% shing.PG 64-22
MO: Tensile Strength (PG 64-22)
4.14.5 4.44.4 4.54.5
0
3
6
-10C -20C -30C
Te
nsile
Str
eng
th [
MP
a]
20% RAPPG 58-28
15% RAP5% shing.PG 58-28
MO: Tensile Strength (PG 58-28)
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 conduct
indirect tensile strength tests
Shingle Asphalt Content
0.0
10.0
20.0
30.0
40.0
50.0
1 2 3 4 5 6 7 8 9 10
Sample
%A
C
ManufactureWaste
Demcon Tear-Off
MN: Asphalt Content of RAS
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.
0.2
2.7
10.0
0.5
5.0
13.5
0.2
5.5
8.2
0
4
8
12
16
0 -10 -20
Temperature [oC]
Stif
fnes
s [G
Pa]
20% RAP15% RAP + 5% Tear-off15% RAP + 5% Manufactured
MN: Mix Stiffness [GPa] @ 500 sec.
0.11.1
5.6
0.2
2.3
8.7
0.1
2.7
5.3
0
4
8
12
16
0 -10 -20
Temperature [oC]
Stif
fnes
s [G
Pa]
20% RAP
15% RAP + 5% Tear-off
15% RAP + 5% Manufactured
MN: Tensile Strength [MPa]
3.2
4.64.8
3.2
4.5
5.1
2.9
4.5
5.3
0.0
2.0
4.0
6.0
0 -10 -20
Temperature [oC]
Tens
ile S
treng
th [M
Pa]
20% RAP
15% RAP + 5% Tear-off
15% RAP + 5% Manufactured
MN vs. MO: Mix Stiffness [GPa] @ 100 sec.
6.1
11.510.0
8.1
16.6
5.0
13.5
2.7
0
4
8
12
16
20
-10C -20C
Temperature [oC]
Stiff
ness
[GPa
]
20% RAP - MO
20% RAP - MN
15% RAP + 5% Tear-off - MO
15% RAP + 5% Tear-off - MN
MN vs. MO: Mix Stiffness [GPa] @ 500 sec.
4.0
7.8
5.65.7
12.9
2.3
8.7
1.1
0
4
8
12
16
20
-10C -20C
Temperature [oC]
Stiff
ness
[GPa
]
20% RAP - MO
20% RAP - MN
15% RAP + 5% Tear-off - MO
15% RAP + 5% Tear-off - MN
States Using RAS
(Justus, September 2004)
Western States
• California• Montana• Texas• Oregon
Other States’ Specifications[and Experiences]
– 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
• Minnesota
(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
7-2(Justus, September 2004)
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)
• 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.
Texas DOT - Conclusions
(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
Testing and Design Procedures
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
AASHTO:Subcommittee on Materials
THOMAS E. BAKER (360) 709-5401 Tumwater, Washington [email protected]
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
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 RAPExample:
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 / AESFiber Tests
As part of the RMRC Project:Environmental Testing of Airborne Particles at
The Shingle Processing PlantApril 2003
Information Sources
EPA Project• CMRA web page
http://www.ShingleRecycling.orgWilliam Turley, Executive Director(630) [email protected]
• Dan Krivit and Associates(651) 489 - [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.”
Key Conclusions
1. Proven and documented2. Quality control is essential3. Economics are driving the market4. Manufacturer shingle scrap recycling is
here today and commercialized5. Tear-off shingle scrap is
under development, but feasible
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