national perspective on rap and green technology · assume threshold level of rap that can be added...
TRANSCRIPT
![Page 1: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/1.jpg)
National Perspective on RAP and Green Technology
Annual Asphalt Contractor’s Workshop Brooklyn Center, Minnesota
March 2, 2010
![Page 2: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/2.jpg)
Outline
• Introduction
• Asphalt-Related Green Technologies – Past, present and future
• The most widely recycled material
• National initiatives
2
![Page 3: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/3.jpg)
Focus on the Environment
• Environment, climate change and sustainability
• Global focus
• Green technologies
3
![Page 4: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/4.jpg)
Old News
• Asphalt pavement is the most widely recycled material
• 100 million tons reclaimed annually • 95% is reused or recycled • $1.8 billion in savings • Reduces demand for new aggregates and
binder and the energy to produce them 4
![Page 5: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/5.jpg)
More Old News
• Beneficial reuse of waste materials and by-products – Slag – Asphalt Shingles – Crumb rubber – Glass – Waste oils – Foundry sands
5
![Page 6: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/6.jpg)
Recent Developments
• Warm Mix Asphalt – Reduced fuel used for heating (15 to 30% reduction) – Reduced Greenhouse Gases – Construction benefits
• Porous or Open Graded Mixes – Reduced noise, improved safety – Improved water quality, stormwater management
6
![Page 7: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/7.jpg)
Recent Developments
• Warm Mix Asphalt – Reduced fuel used for heating (15 to 30% reduction) – Reduced Greenhouse Gases – Construction benefits
• Porous or Open Graded Mixes – Reduced noise, improved safety – Improved water quality, stormwater management
7
![Page 8: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/8.jpg)
Perpetual Pavement • Asphalt pavement designed to last over
50 years without requiring major structural rehabilitation and needing only periodic surface renewal.
• The ultimate in sustainability. – Better use of resources – Reduced CO2 emissions – Reduced energy consumption
8
![Page 9: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/9.jpg)
On the Horizon • Biofuels and Biobinders
– Plant based – Animal based – Algae
• Alternate Energy Sources • Harvesting Energy • Removing Pollutants
– Photocatalytic pavements
9
![Page 10: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/10.jpg)
Carbon Footprint of Roadway Construction
and Maintenance
• Lifecycle assessment • Lower energy consumption and green
house gas emissions than concrete (COLAS, Robinette, Brown, others)
• Perpetual and conventional asphalt pavements lower than concrete during initial construction and 50-year life cycle
10
![Page 11: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/11.jpg)
“Black is Green”
• Asphalt Pavement: – Is 100% recyclable – Uses other recycled materials – Has lower carbon footprint – Is quieter – Provides drainage of water
– Is more sustainable.
11
![Page 12: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/12.jpg)
Today
• Strong incentives to increase RAP use – Increased material and energy costs – Material supply issues – Growing environmental concerns
• Growing demand to – Use RAP in more mixes (i.e. surfaces) – Use higher RAP quantities
12
![Page 13: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/13.jpg)
Typical Asphalt Mix
• 95% aggregate • 5% asphalt binder
Reusing: • Reduces need to quarry more
aggregate • Reduces energy/costs to produce,
process, transport aggregate • Reduces asphalt demand
13
![Page 14: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/14.jpg)
Higher RAP Contents
• Can work – can perform – if properly designed, produced and constructed
• But, need attention to detail
• Some precautions are needed – Many of these are the same as for
aggregate best practices
14
![Page 15: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/15.jpg)
Some Keys to Success
• Processing the RAP
• Stockpiling the RAP
• Control during production
15
![Page 16: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/16.jpg)
In GOK Pile
After Processing
16
![Page 17: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/17.jpg)
Processing RAP
• Mixed RAP can be variable
– Crushing/Screening to break up clumps
– Processing can improve uniformity
– Uniformity essential to meet specifications
17
![Page 18: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/18.jpg)
Fractionating RAP
• Improves uniformity (remixes)
• Allows use of different sizes to meet mix volumetrics
• Allows better control of gradation (and binder content)
18
![Page 19: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/19.jpg)
Stockpiling Practices
• Avoid segregation
• Avoid contamination
• Reduce stockpile moisture – Reduce fuel consumption and drying costs – Increased production capacity
19
![Page 20: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/20.jpg)
But …
Good production and construction has to start with a proper mix design
How do you account for the RAP?
Does it blend?
20
![Page 21: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/21.jpg)
Conventional Wisdom
• RAP contains old, hardened binder that will stiffen the mix
• This will help reduce rutting
• May increase cracking tendencies
• There is research and experience to support conventional wisdom – And some that doesn’t.
21
![Page 22: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/22.jpg)
Possible Effects of RAP Binder
RAP aggregate with oxidized binder film
22
![Page 23: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/23.jpg)
Possible Effects of RAP Binder
RAP aggregate with oxidized binder film plus virgin binder film
23
![Page 24: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/24.jpg)
Possible Effects of RAP Binder
If RAP and virgin binders do not blend, effective binder properties will be those of the virgin binder only.
24
![Page 25: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/25.jpg)
Possible Effects of RAP Binder
If RAP and virgin binders blend or merge, effective binder properties will be determined by the amount of blending that occurs.
25
![Page 26: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/26.jpg)
Current Guidelines • Assume that significant blending occurs • Assume threshold level of RAP that can be
added without affecting effective binder grade – 0 to 15% RAP, no binder grade change – 16-25% RAP, decrease virgin binder grade – Over 25% RAP, test RAP binder to determine
appropriate virgin grade (or allowable RAP content)
• Based on non-fractionated mixes with about 5% binder in RAP and new mix.
26
![Page 27: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/27.jpg)
Impacts of Blending on Performance
• If we assume there is blending and there isn’t, virgin binder grade may be softer than desired. – Increased chance for rutting – Decreased chance for cracking
• If we assume there is no blending and there is, effective binder grade may be stiffer than desired. – Decreased chance for rutting – Increased chance for cracking
27
![Page 28: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/28.jpg)
Risks of False Assumptions • Assuming there is blending may be more
conservative. – Shouldn’t rely on binder to control rutting – Increased cracking can have performance and
economic impacts
• But, if RAP binder does not blend and act like binder, mix could be under-asphalted.
• Current guidelines are a starting point, but not the definitive answer
28
![Page 29: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/29.jpg)
Better options
• Know a reasonable threshold level for your typical materials.
• Above threshold, know if blending is occurring or not.
• Contractors, know and manage RAP stockpiles to control the assumptions.
• But how? 29
![Page 30: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/30.jpg)
Threshold Values
• Test and know your typical RAP materials (recommended at state level) – What kinds of binder did you use? – How much aging is typical? – How stiff are typical RAP binders? – Extract and grade RAP binders, mixes
• Based on testing and experience, some states have changed the tiers – Say, up to 20% RAP without changing grade
30
![Page 31: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/31.jpg)
Mixture Testing
• Test lab mixes at various RAP contents with different binder grades
• Test plant produced mixes
• Suggested mixture tests – Dynamic modulus – Indirect tensile strength – Other familiar tests
31
![Page 32: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/32.jpg)
Blending - Bonaquist approach
• Measure mix dynamic modulus • Develop master curve
– Stiffness over range of temperatures and loading rates
• Estimate effective binder modulus in mix – Hirsch model uses binder shear modulus
and mix volumetrics to estimate mix stiffness
32
![Page 33: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/33.jpg)
Blending - Bonaquist approach
• Extract and recover binder (total blending) • Measure binder shear modulus • Compare binder modulus and effective
binder modulus from mix – Overlap indicates good mixing
33
![Page 34: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/34.jpg)
9.5 mm with PG 64-22, Batch Plant
1.0E+00
1.0E+01
1.0E+02
1.0E+03
1.0E+04
1.0E+05
1.0E+06
1.0E-04 1.0E-02 1.0E+00 1.0E+02 1.0E+04 1.0E+06 1.0E+08
Reduced Frequency, rad/sec
Bin
der G
*, kP
a
From Mix
Recovered Binder
Advanced Asphalt Technologies, LLC
“Engineering Services for the Asphalt Industry”
34
![Page 35: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/35.jpg)
9.5 mm with PG 64-22 + 5% RAS, Batch Plant
1.0E+00
1.0E+01
1.0E+02
1.0E+03
1.0E+04
1.0E+05
1.0E+06
1.0E-04 1.0E-02 1.0E+00 1.0E+02 1.0E+04 1.0E+06 1.0E+08
Reduced Frequency, rad/sec
Bin
der G
*, kP
a
From Mix
Recovered Binder
Advanced Asphalt Technologies, LLC
“Engineering Services for the Asphalt Industry”
35
![Page 36: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/36.jpg)
9.5 mm with PG 64-22 + 35 % FRAP, Double Barrel
1.0E+00
1.0E+01
1.0E+02
1.0E+03
1.0E+04
1.0E+05
1.0E+06
1.0E-04 1.0E-02 1.0E+00 1.0E+02 1.0E+04 1.0E+06 1.0E+08
Reduced Frequency, rad/sec
Bin
der G
*, kP
a
PG 64-22 With 35 % RAPFrom Mix Modulus
PG 64-22 With 35% RAPFrom Recovered Binder
Advanced Asphalt Technologies, LLC
“Engineering Services for the Asphalt Industry”
36
![Page 37: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/37.jpg)
Bonaquist Approach
• Advantage – allows assessment of production variables – RAP processing – Production rates and temperatures – Additives – Storage time, etc.
• More information Hot Mix Asphalt
Technology, September/October 2007. 37
![Page 38: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/38.jpg)
RAP Agg Specific Gravity
• Estimate from RAP binder content, RAP Gmm and estimated binder absorption
• Measure after extraction or ignition oven
• Requires knowledge of typical materials
• Impact of errors in estimation increase as RAP content increases
38
![Page 39: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/39.jpg)
National Initiatives
• FHWA Policy on Recycling • NAPA and ARRA cooperative
agreement to double rate of reuse/recycling within five years
• Environmental rating systems for roads
39
![Page 40: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/40.jpg)
HMA Recycling ETG • FHWA initiated in May 2007 • Coordinate, develop national guidance and
recommendations on RAP use • Goals – encourage all states to allow 15-20%
RAP, then increase some to 25-30% • Demo projects, document performance, share
info, best practices, research • www.morerap.us
40
![Page 41: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/41.jpg)
WMA Technical Working Group
• Discuss issues and share experiences to advance development and implementation of WMA in the US
• www.warmmixasphalt.com
41
![Page 42: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/42.jpg)
National RAP Research
• NCHRP 9-46, Improved Mix Design, Evaluation and Materials Management of High RAP Content HMA
• FHWA Funded, Development of High RAP Content Mix Guidelines and Informational Documents
• Other state and FHWA funded studies ongoing
42
![Page 43: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/43.jpg)
WMA Research • NCHRP 9-43, Mix Design Practices for Warm
Mix Asphalt (in publication) • 9-47A, Properties and Performance of Warm
Mix Asphalt Technologies • 9-49, Performance of WMA Technologies:
Stage I--Moisture Susceptibility • 9-49A Stage II--Long-Term Field Performance • State and other research
43
![Page 44: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/44.jpg)
Summary
• RAP, WMA and Perpetual Pavements are sustainable today
• Future advances will continue to improve the sustainability of asphalt
• Tools and resources are available to help you today and tomorrow.
44
![Page 45: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/45.jpg)
Sustainability
Meeting the needs of the present without compromising the ability of future generations
to meet theirs.
![Page 46: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/46.jpg)
Ancient Greek Proverb
A society grows great when old men plant trees in whose shade
they will not sit.
![Page 47: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/47.jpg)
Modern Mash Up
A society is sustainable when people pave roads their
children can recycle.
![Page 48: National Perspective on RAP and Green Technology · Assume threshold level of RAP that can be added without affecting effective binder grade – 0 to 15% RAP, no binder grade change](https://reader033.vdocuments.us/reader033/viewer/2022060909/60a4102626ddc05d345cfcc0/html5/thumbnails/48.jpg)
Rebecca S. McDaniel
Technical Director North Central Superpave Center
Purdue University West Lafayette, IN
765/463-2317 ext 226 [email protected]