Presentation Outline
2/26/2018
Engineering Properties of Rubber Modified Asphalt and Benefits to Asphalt Highway Construction Session: 352F H. Barry Takallou, Ph.D., P.E. President & CEO (949) 263-9100
Presentation Outline I.
Production of Ground Tire Rubber (GTR)
II.
Engineering Properties of Rubber Modified Asphalt A.
Benefits of GTR in Asphalt Binders
B.
Benefits of GTR on Performance of Rubber Modified Asphalt Pavements
C.
Physical & Chemical Specification Requirements for GTR in Asphalt Pavements
III.
Market Potential for GTR in US Asphalt Pavements
IV.
Concerns Highway Agencies Have Over Routine Use of Rubber Modified Asphalt & How These Concerns Have Been Addressed
V.
Summary
1
2/26/2018
From Scrap Tires to Rubber Modified Asphalt Pavements
I.
Production of GTR – Cryogenic Processing – Ambient Processing
Cryogenic Production of GTR
Whole tires are shredded to 2” chips then fed into the cryogenic production line
The freeze chamber is rotating with a slow speed to reduce tire granulate temperature from ambient to glass transition temperature of -180oc (-290of)
The liquid nitrogen is injected from a 30,000 gal tank into the freeze chamber
The frozen tire granulates are discharged from the end of the freeze tunnel by gravity into the three hammer mills
2
2/26/2018
Cryogenic Production Line
Ambient Production of GTR
Whole tires are shred into 2” chips then continue through production at ambient temperature
The chips are fed into the Granulation Department where the chips are reduced further in size while separating steel & fabric
The Grinding Department finalizes the size of the GTR for final packaging
Ambient Production Line
3
2/26/2018
Finished Product and Bagging
II. Engineering Properties of Rubber Modified Asphalt A.
Benefits of GTR in Asphalt Binders
B.
Benefits of GTR on Performance of Rubber Modified Asphalt Pavements
C.
Physical & Chemical Specification Requirements for GTR in Asphalt Pavements
Conventional vs. Rubber Modified Asphalt Mixes
Conventional Asphalt Mix: – 5.5% Liquid Bitumen Asphalt – 94.5% Aggregate
Asphalt Rubber Mix: – 6% Liquid Bitumen Asphalt – 1.5% GTR – 92.5% Aggregate
4
2/26/2018
Conventional vs. Rubber Modified Asphalt Surfaces
Why does it work? 22,937,600 rubber particles per ton of mix enhances performance of asphalt pavement
www.rubberpavements.org
Typical Chemical Components of a Tire
Typical Composition: 55% Polymer, 30% Carbon Black, 9% Process Oil, 6% Ash
Polymers: A blend of Natural Rubber, Styrene-Butadiene Rubber (SBR), Butadine Rubber (BR). These are vulcanized, A.K.A. sulfurcrosslinked
5
2/26/2018
II-A. Benefits of GTR in Asphalt Binder Properties
Reduces temperature susceptibility of asphalt binder
Increases elastic properties of asphalt binder
Reduces plastic properties of asphalt binder
Why Asphalt Rubber Mixes are More Durable – Increases Asphalt Binder Film Thickness on the Aggregate
The physical interaction between GTR and asphalt binder
www.rubberpavements.org
6
2/26/2018
Visco-Elastic Properties of Conventional Asphalt Binder
Visco-Elastic Properties of Conventional vs. Rubber Asphalt Binders in Cold Temperatures
I-10 West of Phoenix Dense Graded 8 year period Cracked Condition
I-10 West of Phoenix Asphalt Rubber Gap Graded 8 year period No cracks
Cracking
7
2/26/2018
Visco-Elastic Properties of Asphalt Rubber Binder in Hot Temperature
Rutting
II-B. Benefits of GTR on Performance of Asphalt Rubber Pavements
Increased Durability
Increased Fatigue Life
Reduces Permanent Deformation (Rutting)
8
2/26/2018
Differences Between Asphalt Rubber vs. Conventional Pavements
Asphalt rubber binder is less temperature sensitive, therefore making the asphalt rubber pavement less temperature sensitive It allows use of larger size aggregate and more stones in aggregate structure It allows more binder in the mix without bleeding or flushing
Aggregate Gradation Comparison
Open Graded
Gap Graded
Dense Graded
Use with Rubber
Marshall & Hveem Mixes 5.1 % Asphalt Air Voids 5.9 % 16.5 % VMA Asphalt Rubber Gap Graded Mix 7.3 % Asphalt Air Voids 5.2 % 20.2 % VMA
9
2/26/2018
SMA Mixes 5.5 % Asphalt Air Voids 4.9 % 16.0 % VMA Asphalt Rubber Gap Graded Mix 7.3 % Asphalt Air Voids 5.2 % 20.2 % VMA
Asphalt Rubber Open Graded Mix 9.2 % Asphalt Rubber Air Voids 20.2 % VMA 32.5 %
Asphalt Rubber Gap Graded Mix 7.3 % Asphalt Air Voids 5.2 % 20.2 % VMA
AR Open Graded (ARFC) and Gap Graded (ARAC) Gradation
II-C: Physical & Chemical Specification Requirements for GTR in Asphalt Pavements
10
2/26/2018
Typical GTR Gradation Specification For Asphalt Rubber Modifiers Sieve Size
Scrap Tire CRM Passing ( % )
High Natural CRM Passing ( % )
100
No. 8
100
No. 10
98 – 100
100
No. 16
45 – 75
95 – 100
No. 30
2 – 20
35 – 85
No. 50
0–6
10 – 30
No. 100
0–2
0–4
No. 200
__
0–1
Typical GTR Chemical Specification For Asphalt Rubber Modifiers T est Parameter
Min. %
Max.%
6.0
16.0
Ash Content
---
8.0
Carbon Black Content
28.0
38.0
Rubber Hydrocarbon
42.0
65.0
Natural Rubber Content
22.0
39.0
Acetone Extract
Typical High Natural GTR Chemical Specification For Asphalt Rubber Modifiers T est Parameter
Min. %
Max.%
4.0
16.0
Rubber Hydrocarbon
50.0
---
Natural Rubber Content
40.0
48.0
Acetone Extract
11
2/26/2018
III. Market Potential for GTR in U.S. Asphalt Pavements
Approximately 375 million tons of Hot Mix Asphalt is used in the U.S. annually
Approximately 280 million scrap tires are generated in the U.S. annually
Potentially 3 billion lbs of GTR is available for consumption in US road and highway construction annually
Based on 30 lbs per ton of mix or 1.5% by total weight of mix, 3 billion lbs of GTR can modify 100 million tons or 25% of the total U.S. conventional asphalt consumption annually
California DOT has a policy to pave top surface roadways with rubber modified asphalt, which is approximately 35% of its annual asphalt consumption. To date, California has successfully paved approximately 22,000 miles of its roadway system with rubber modified asphalt.
Typical Cost Analysis of Conventional vs. Rubber Asphalt Pavements
Bulk Specific Gravity: – Asphalt Rubber Pavement (AR) = 150 lbs/ft3 – Conventional Asphalt Pavement (AC) = 155 lbs/ft3
1 lane mile = 5,280’ long, 12’ wide, 2” thick
Tons per lane mile required by type: – AR: – AC:
5,280’ x 12’ x 2”/12 x 150 lbs/ft3 = 1,584,000 lbs or 792 tons 5,280’ x 12’ x 2”/12 x 150 lbs/ft3 = 1,636,800 lbs or 818 tons
12
2/26/2018
Typical Cost of Conventional vs. Rubber Modified Asphalt Mixes: – Conventional AC Mix: $50 per ton – Rubber Modified AC Mix: $60 per ton
Typical Cost of Conventional vs. Rubber Modified Asphalt Mixes per Lane Mile: – AC: 818 tons x $50 = $40,900 – AR: 792 tons x $60 = $47,520 – A difference of $6,620
IV. Concerns Highway Agencies Have Over Routine Use of Rubber Modified Asphalt - How These Concerns Have Been Addressed
Typical Concerns About Routine Use of Rubber Modified Asphalt:
Not Cost Effective – See Life Cycle Cost Analysis of Asphalt-Rubber Paving Materials Authored by Hicks, R. Gary, P.E., Oregon State University & Epps, Jon A., P.E., University of Nevada, Reno (RPA)
Only W orks in W arm Climate – Asphalt rubber is used in Massachusetts, New Hampshire and New Jersey successfully
13
2/26/2018
Changes to Asphalt Paving Equipment Are Needed – See FHW A Report to Congress*
Cannot Be Recycled – See FHW A Report to Congress*
Worker Safety – See FHW A Report to Congress* *http://www.rubberpavements.org/ARTIC/Emissions/ARTIC_Emission s_RPA_A1001.html
FHWA Report to US Congress Addresses Most of the Highway Agencies Concerns
Asphalt rubber does not increase the threat to human health or environment as compared to the threats associated with conventional HMA pavements.
Asphalt rubber can be recycled just like conventional HMA pavements.
Asphalt rubber performs as good as conventional HMA pavements.
V. Summary
GTR increases elastic properties of asphalt binder and reduces its plastic property
The use of GTR in asphalt pavements reduces temperature susceptibility of pavements under cold and hot environmental conditions
It is important to follow chemical and physical specification requirements in order for GTR to be compatible with aggregate and asphalt rubber binders
14
2/26/2018
Highway Agency concerns have been addressed by the FHWA Report to Congress stating that asphalt rubber does not increase threat to human or environmental health, it can be recycled and performs as good as conventional asphalt pavements
For the past 30 years, California DOT has been using rubber modified asphalt and has 22,000 miles in service. They have found that asphalt rubber is more cost effective than conventional asphalt
Contact: Barry Takallou, Ph.D., P.E. President & CEO CRM Company 1301 Dove Street, Suite 940 Newport Beach, CA, 92660, U.S.A. Phone 949.263.9100 Email [email protected]
Thank You Session Evaluations/PDH’s
See you again at:
• World of Asphalt 2019 • Professional • February 12-14, 2019 Development Hours • Indianapolis, IN logged in session feedback. • CONEXPO – CON/AGG 2020 • Complete session • March 10-14, 2020 feedback in mobile app. • Las Vegas, NV • Answer “Yes” to last • 140+ education sessions questions for PDH’s
#WorldofAsphalt
15
Engineering Properties of Rubber Modified Asphalt and Benefits to Asphalt Highway Construction Session: 352F H. Barry Takallou, Ph.D., P.E. President & CEO (949) 263-9100
Presentation Outline I.
Production of Ground Tire Rubber (GTR)
II.
Engineering Properties of Rubber Modified Asphalt A.
Benefits of GTR in Asphalt Binders
B.
Benefits of GTR on Performance of Rubber Modified Asphalt Pavements
C.
Physical & Chemical Specification Requirements for GTR in Asphalt Pavements
III.
Market Potential for GTR in US Asphalt Pavements
IV.
Concerns Highway Agencies Have Over Routine Use of Rubber Modified Asphalt & How These Concerns Have Been Addressed
V.
Summary
1
2/26/2018
From Scrap Tires to Rubber Modified Asphalt Pavements
I.
Production of GTR – Cryogenic Processing – Ambient Processing
Cryogenic Production of GTR
Whole tires are shredded to 2” chips then fed into the cryogenic production line
The freeze chamber is rotating with a slow speed to reduce tire granulate temperature from ambient to glass transition temperature of -180oc (-290of)
The liquid nitrogen is injected from a 30,000 gal tank into the freeze chamber
The frozen tire granulates are discharged from the end of the freeze tunnel by gravity into the three hammer mills
2
2/26/2018
Cryogenic Production Line
Ambient Production of GTR
Whole tires are shred into 2” chips then continue through production at ambient temperature
The chips are fed into the Granulation Department where the chips are reduced further in size while separating steel & fabric
The Grinding Department finalizes the size of the GTR for final packaging
Ambient Production Line
3
2/26/2018
Finished Product and Bagging
II. Engineering Properties of Rubber Modified Asphalt A.
Benefits of GTR in Asphalt Binders
B.
Benefits of GTR on Performance of Rubber Modified Asphalt Pavements
C.
Physical & Chemical Specification Requirements for GTR in Asphalt Pavements
Conventional vs. Rubber Modified Asphalt Mixes
Conventional Asphalt Mix: – 5.5% Liquid Bitumen Asphalt – 94.5% Aggregate
Asphalt Rubber Mix: – 6% Liquid Bitumen Asphalt – 1.5% GTR – 92.5% Aggregate
4
2/26/2018
Conventional vs. Rubber Modified Asphalt Surfaces
Why does it work? 22,937,600 rubber particles per ton of mix enhances performance of asphalt pavement
www.rubberpavements.org
Typical Chemical Components of a Tire
Typical Composition: 55% Polymer, 30% Carbon Black, 9% Process Oil, 6% Ash
Polymers: A blend of Natural Rubber, Styrene-Butadiene Rubber (SBR), Butadine Rubber (BR). These are vulcanized, A.K.A. sulfurcrosslinked
5
2/26/2018
II-A. Benefits of GTR in Asphalt Binder Properties
Reduces temperature susceptibility of asphalt binder
Increases elastic properties of asphalt binder
Reduces plastic properties of asphalt binder
Why Asphalt Rubber Mixes are More Durable – Increases Asphalt Binder Film Thickness on the Aggregate
The physical interaction between GTR and asphalt binder
www.rubberpavements.org
6
2/26/2018
Visco-Elastic Properties of Conventional Asphalt Binder
Visco-Elastic Properties of Conventional vs. Rubber Asphalt Binders in Cold Temperatures
I-10 West of Phoenix Dense Graded 8 year period Cracked Condition
I-10 West of Phoenix Asphalt Rubber Gap Graded 8 year period No cracks
Cracking
7
2/26/2018
Visco-Elastic Properties of Asphalt Rubber Binder in Hot Temperature
Rutting
II-B. Benefits of GTR on Performance of Asphalt Rubber Pavements
Increased Durability
Increased Fatigue Life
Reduces Permanent Deformation (Rutting)
8
2/26/2018
Differences Between Asphalt Rubber vs. Conventional Pavements
Asphalt rubber binder is less temperature sensitive, therefore making the asphalt rubber pavement less temperature sensitive It allows use of larger size aggregate and more stones in aggregate structure It allows more binder in the mix without bleeding or flushing
Aggregate Gradation Comparison
Open Graded
Gap Graded
Dense Graded
Use with Rubber
Marshall & Hveem Mixes 5.1 % Asphalt Air Voids 5.9 % 16.5 % VMA Asphalt Rubber Gap Graded Mix 7.3 % Asphalt Air Voids 5.2 % 20.2 % VMA
9
2/26/2018
SMA Mixes 5.5 % Asphalt Air Voids 4.9 % 16.0 % VMA Asphalt Rubber Gap Graded Mix 7.3 % Asphalt Air Voids 5.2 % 20.2 % VMA
Asphalt Rubber Open Graded Mix 9.2 % Asphalt Rubber Air Voids 20.2 % VMA 32.5 %
Asphalt Rubber Gap Graded Mix 7.3 % Asphalt Air Voids 5.2 % 20.2 % VMA
AR Open Graded (ARFC) and Gap Graded (ARAC) Gradation
II-C: Physical & Chemical Specification Requirements for GTR in Asphalt Pavements
10
2/26/2018
Typical GTR Gradation Specification For Asphalt Rubber Modifiers Sieve Size
Scrap Tire CRM Passing ( % )
High Natural CRM Passing ( % )
100
No. 8
100
No. 10
98 – 100
100
No. 16
45 – 75
95 – 100
No. 30
2 – 20
35 – 85
No. 50
0–6
10 – 30
No. 100
0–2
0–4
No. 200
__
0–1
Typical GTR Chemical Specification For Asphalt Rubber Modifiers T est Parameter
Min. %
Max.%
6.0
16.0
Ash Content
---
8.0
Carbon Black Content
28.0
38.0
Rubber Hydrocarbon
42.0
65.0
Natural Rubber Content
22.0
39.0
Acetone Extract
Typical High Natural GTR Chemical Specification For Asphalt Rubber Modifiers T est Parameter
Min. %
Max.%
4.0
16.0
Rubber Hydrocarbon
50.0
---
Natural Rubber Content
40.0
48.0
Acetone Extract
11
2/26/2018
III. Market Potential for GTR in U.S. Asphalt Pavements
Approximately 375 million tons of Hot Mix Asphalt is used in the U.S. annually
Approximately 280 million scrap tires are generated in the U.S. annually
Potentially 3 billion lbs of GTR is available for consumption in US road and highway construction annually
Based on 30 lbs per ton of mix or 1.5% by total weight of mix, 3 billion lbs of GTR can modify 100 million tons or 25% of the total U.S. conventional asphalt consumption annually
California DOT has a policy to pave top surface roadways with rubber modified asphalt, which is approximately 35% of its annual asphalt consumption. To date, California has successfully paved approximately 22,000 miles of its roadway system with rubber modified asphalt.
Typical Cost Analysis of Conventional vs. Rubber Asphalt Pavements
Bulk Specific Gravity: – Asphalt Rubber Pavement (AR) = 150 lbs/ft3 – Conventional Asphalt Pavement (AC) = 155 lbs/ft3
1 lane mile = 5,280’ long, 12’ wide, 2” thick
Tons per lane mile required by type: – AR: – AC:
5,280’ x 12’ x 2”/12 x 150 lbs/ft3 = 1,584,000 lbs or 792 tons 5,280’ x 12’ x 2”/12 x 150 lbs/ft3 = 1,636,800 lbs or 818 tons
12
2/26/2018
Typical Cost of Conventional vs. Rubber Modified Asphalt Mixes: – Conventional AC Mix: $50 per ton – Rubber Modified AC Mix: $60 per ton
Typical Cost of Conventional vs. Rubber Modified Asphalt Mixes per Lane Mile: – AC: 818 tons x $50 = $40,900 – AR: 792 tons x $60 = $47,520 – A difference of $6,620
IV. Concerns Highway Agencies Have Over Routine Use of Rubber Modified Asphalt - How These Concerns Have Been Addressed
Typical Concerns About Routine Use of Rubber Modified Asphalt:
Not Cost Effective – See Life Cycle Cost Analysis of Asphalt-Rubber Paving Materials Authored by Hicks, R. Gary, P.E., Oregon State University & Epps, Jon A., P.E., University of Nevada, Reno (RPA)
Only W orks in W arm Climate – Asphalt rubber is used in Massachusetts, New Hampshire and New Jersey successfully
13
2/26/2018
Changes to Asphalt Paving Equipment Are Needed – See FHW A Report to Congress*
Cannot Be Recycled – See FHW A Report to Congress*
Worker Safety – See FHW A Report to Congress* *http://www.rubberpavements.org/ARTIC/Emissions/ARTIC_Emission s_RPA_A1001.html
FHWA Report to US Congress Addresses Most of the Highway Agencies Concerns
Asphalt rubber does not increase the threat to human health or environment as compared to the threats associated with conventional HMA pavements.
Asphalt rubber can be recycled just like conventional HMA pavements.
Asphalt rubber performs as good as conventional HMA pavements.
V. Summary
GTR increases elastic properties of asphalt binder and reduces its plastic property
The use of GTR in asphalt pavements reduces temperature susceptibility of pavements under cold and hot environmental conditions
It is important to follow chemical and physical specification requirements in order for GTR to be compatible with aggregate and asphalt rubber binders
14
2/26/2018
Highway Agency concerns have been addressed by the FHWA Report to Congress stating that asphalt rubber does not increase threat to human or environmental health, it can be recycled and performs as good as conventional asphalt pavements
For the past 30 years, California DOT has been using rubber modified asphalt and has 22,000 miles in service. They have found that asphalt rubber is more cost effective than conventional asphalt
Contact: Barry Takallou, Ph.D., P.E. President & CEO CRM Company 1301 Dove Street, Suite 940 Newport Beach, CA, 92660, U.S.A. Phone 949.263.9100 Email [email protected]
Thank You Session Evaluations/PDH’s
See you again at:
• World of Asphalt 2019 • Professional • February 12-14, 2019 Development Hours • Indianapolis, IN logged in session feedback. • CONEXPO – CON/AGG 2020 • Complete session • March 10-14, 2020 feedback in mobile app. • Las Vegas, NV • Answer “Yes” to last • 140+ education sessions questions for PDH’s
#WorldofAsphalt
15
