Rubberized Asphalt

Cost Savings | Safety | Noise Reduction | Durability

ADVANTAGES : RUBBERIZED ASPHALT

Liberty Quick Facts

• Founded in 2000

• 150 Million Scrap Tires Annually (~50%)

• Over 30 Collection & Processing Facilities

Throughout the US & Canada

• Over 1600 Employees in North America

• Corporate Headquarters in Pittsburgh, PA

Diverse End Products

• Tire Derived Fuel

• Infill Track Rubber for Synthetic Turf Installers/Track Companies

• Rubber Mulch for Big Box (Lowes/Home Depot/Wal-Mart) Retail/Commercial Markets

• Industrial Molding & Other Industrial Applications

• Asphalt & Related Markets!

Markets for

Recycled Tire Material

Two Basic Rubberized

Asphalt Binders

• Asphalt-Rubber

– 15% GTR content or more

– 40 years of use and performance

– ASTM D6114 and over ten different Sate DOT Specifications, and over 20 different countries.

– Gradation 10-50 mesh

– Uses Older Tests, Before Super Pave

• Performance Graded Rubber Modified Binder

– Around 10% GTR content

– New technology, in use in the last 5 years

– GTR is allowed as an alternative to Polymer Modified Asphalt to meet a Performance Grade (PG) 76-22

– In use in 5 state DOTs in 2011

– Uses a 30 minus (to fit into the current testing)

– Can comply with Super Pave

Oil, Asphalt and Gas

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$/G

allo

n

Asphalt Crude Oil Gasoline

Crude Oil, Gas and Asphalt

Costs

Tire

Processing

Tire Processing

GTR Production

AMBIENT GRINDING PROCESS:

GTR Production

GRINDING BY CRYOGENIC PROCESS:

(a) Tires fragmentation

(b) Cryogenic tunnel

(c) Granulators

(d) Final step

Steel Is Removed

Form of GTR

CRM 5 R4

CRM 5 R4 AMBIENT GRINDING CRYOGENIC PROCESS

alt on

Physi

cal

Prope

rties

of

GTR

GTR Particle Swelling

Figures courtesy of: Abdelrahman, 2004

Grinding Methods

Cryogenic

Ambient

Ambient Truck Tire

Ambient Truck Tire

Cryogenic Truck

Cryogenic Truck

• No. 10 mesh and

smaller is used

(less than 2 mm)

• Free of wire and

other

contaminants

• 0.5% fiber or less.

Granulated Tire Rubber

Composite Power 45 Chart

0

20

40

60

80

100

Sieve Size Raised to 0.45 Power

% P

ass

ing

Maximum Density

Gap Grade

Dense Grade

Open Grade

SMA

#REF!

#REF!

Linear (Maximum

Density)

12.7 190.075 2.36 4.75 25

Where the rubber lives

GTR Composition

“Polymer Plus’

CARBON BLACK

ANTI-OXIDANTS and

ANTI-OZONATES

NATURAL RUBBER

POLYMERS AND

THERMOPLASTIC

ELASTOMERS

SBR STYRENE-BUTADIENE

and OTHER SYNTHETIC RUBBERS

GTR

Rubber Must Be Present to be “Rubberized” Asphalt

Rubber, noun – Material that is capable of recovering from large deformations quickly and forcibly, and can be, or already is, modified to a state that it is essentially insoluble (but can swell) in boiling solvent, such as benzene, methyl ethyl ketone, or ethanol-toluene azeotrope.

ASTM D1566 – 10e1 Standard Terminology Relating to Rubber

Rubber Defined

24

Basic Terminology –

Rubberized Asphalt

• Plant Mix process - rubber component added to the

mix in the drum

– Not reacted in 1990s, large particle, too absorptive (2-3% of mix)

– New technologies - Rubber can be pre-reacted or pre-blended

with modifiers or ―compatibilizers‖.

– 30 minus rubber, ~10%of binder (0.5% of mix)

– Can work with Dense Grades and Reclaimed Asphalt Pavement

(RAP) Mixes

• Wet process - Rubber is added to the liquid asphalt

first (reacted)

– Most common method of introducing tire rubber to asphalt

– Equipment and Storage Needs

25

Basic Terminology – Rubberized

Asphalt

• Wet Process

– Asphalt Rubber (15% + Rubber and Other

Additives Optional)

– GTR Modified with Suspending Agent or other

additives (30 mesh rubber, 8-12% content)

– Terminal blend (dissolved rubber, a recycled

polymer modified asphalt)

• AC-20-5TR

• MAC-10TR

• PG 76-22TR

Performance Graded Asphalt

*Presently, only liquid modifiers are allowed in the PG 76-22 range in most states.

Ground tire rubber has been proven to improve asphalt properties but is excluded from

some specifications and applications. Some state DOTs have made the ―text change‖ to

allow GTR Modifiers where ever virgin polymers are used.

Tire Rubber Performs In A Wider

Range Of Temperatures than Asphalt

Rubberized Asphalt is Triple Green

Recycled Materials Have To Perform

Better, Save Money, and be

Sustainable

San Antonio I-35

Safety in Wet Weather

ENHANCE : SAFETY

Reduces Hydroplaning I-35, San Antonio, Texas

Accident and Climatic Conditions Before and After AR Friction Course Overlay

Climate data obtained from National Oceanographic and Atmospheric Administration and accident data from San Antonio Police Department.

BEFORE

July 2001 – June 2002

AFTER

November 2002 – October 2003

Total Precipitation

31.78 inches

32.63 inches

Days with Measurable Precipitation

69

99

Days with Trace of Precipitation

38

45

Total Days with Precipitation

107

144

Major Accidents with Emergency

Response Vehicle Dispatch

85

48

Major Accidents on Wet Weather Days

39

19

ENHANCE : SAFETY

REDUCE : NOISE

Noise Values Reduced 10 Decibels

• Reducing noise at the source saves money and

improves quality of life along highways.

REDUCE : NOISE

IMPROVE : DURABILITY

Cold Weather Performance

• Implementation in Canadian provinces and

Northern states proves cold weather durability.

• Used in Alaska and Sweden for studded tire wear

resistance and as a surface ice de-bonding material

IMPROVE : DURABILITY

Rubber friction course on I-78 in

New Jersey.

Rubberized asphalt

overlay on I-295 in

Massachusetts.

CHOOSE : GREEN

Practical Reuse for Scrap Tires • A 1-mile section of four-lane highway uses up to

8,000 tires to create a safe, durable road.

• Recycle your communities tires into high value public assets —

ROADS!

South Carolina

Florida

North Carolina

Washington, D.C.

Delaware

New Jersey

Connecticut

Rhode Island

Massachusetts

Maine

New Hampshire

Vermont

New York

Ohio

Kentucky

West Virginia

Pennsylvania

Indiana Illinois

Iowa

Missouri

Arkansas

Tennessee

Georgia Alabama

Mississippi

Louisiana

Texas

Oklahoma

Nebraska

Kansas

South Dakota

North Dakota

Virginia

New Mexico

Arizona

Colorado Utah

Nevada

California

Alaska

Minnesota

Wisconsin

Michigan

Montana

Wyoming

Idaho

Oregon

Washington

Maryland

Hawaii

Rubber used

Not using rubber

States Where Tire Rubber is Used in Asphalt (DOT Spec or Special Provision)

The time (July 2008) when crude oil price hit $147 per barrel

0

100

200

300

400

500

600

700

800

900

1000

1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec

Asphalt ($/ton)

Polymer mod ($/ton)

Alternative Modifiers Needed

Parall

el

Plate

DSR • Works with fine grinds

• Sample too small for coarse grinds

Coarse Rubber and Fine Rubber

&

Bob

Confi

gurati

on

Top View

• Malvern Instruments

– Kinexus Pro Rheometer

• Active Heated Chamber

– Used with 25mm parallel plates

• Peltier Cylinder Cartridge

– Used with Cup & Bob and Cup & Vane

New DSR Configuration

NCAT GTR

Performance Grade Study

• 11 rubber sizes and sources

• 10% Rubber Content

– One binder had 15%

• PG 67-22 Base Binder

• Graded by Following AASHTO specification

• 1 mm gap on DSR

– Only one had particulate where 2 mm gap is

needed

• Binders will be put into OGFC mixes and

tested

GTR

Source

Original

DSR

RTFO DSR PAV DSR BBR – S BBR – m True Grade

1 83.6 87.0 17.1 -34.8 -24.9 83.6 – 24.9

2 72.8 77.8 19.4 -31.2 -25.1 72.8 – 25.1

3 80.4 88.0 15.6 -36.1 -24.2 80.4 – 24.2

4 79.0 86.7 17.1 -35.6 -23.0 79.0 – 23.0

5 77.9 82.0 17.6 -35.8 -25.6 77.9 – 25.6

6 80.7 85.6 17.7 -34.5 -23.6 80.7 – 23.6

GTR

Source

Original

DSR

RTFO DSR PAV DSR BBR – S BBR – m True Grade

7 83.1 87.1 15.9 -36.9 -24.6 83.1 – 24.6

8

(2mm gap)

76.3 129.3 15.6 -47.3 -21.8 76.3 – 21.6

9 82.8 86.8 17.2 -34.1 -23.1 82.8 – 23.1

10 82.2 86.2 16.4 -36.3 -23.2 82.2 – 23.2

11

(same as

ten but

15%)

86.7 91.0 17.1 -22.0 -19.3 86.7 – 19.3

Observations

• GTR can be used to modify asphalt and achieve

PG 76

• Source of components can affect gradeRubber

content can be adjusted to affect top end

• Other additives may be needed to control bottom

end

• Other studies have shown the importance of

base binder prior to rubber modification

Rubberized Asphalt Can Meet and Exceed Expectations

• Successful field performance in

over 15 states

• Over 20 years of research

• Comparative tests easily and

quickly prove Rubber Modified

Binder Performance next to a

Polymer Modified Binder

PERFORMANCE

• Rutting testing Jan. 2004

• Fatigue testing (100-mm) Mar. 2006

• Fatigue testing (150-mm) Dec. 2007

Two FHWA ALFs with

12 Pavement Lanes Constructed in

the Summer and Fall of 2002

As-Built Pavement Lanes

CR-AZ ---- 70-22

1

PG 70-22 Control

2

Air Blown

3

SBS LG

4

CR-TB

5

TP

6

PG 70-22

+ Fibers

7

PG 70-22

8

SBS 64-40

9

Air Blown

10

SBS LG

11

TP

12

Lane 1

CR-AZ

300,000

Lane 2

Control

100,000

Lane 3

Air Blown

100,000

Lane 4

SBS LG

300,000

Lane 5

CR-TB

100,000

Lane 6

TP

200,000

ALF Lanes in

Overlay Tester

Percentage of Area Cracked vs. ALF Wheel Load Passes

0.0

20.0

40.0

60.0

80.0

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120.0

0 50000 100000 150000 200000 250000 300000 350000

Number of ALF Passes

Pe

rce

nta

ge

of

Are

a C

rac

ke

d, %

L2S3 (Control)

L3S3 (Air Blown)

L5S3 (CR-TB)

L6S3 (Terpolymer)

L4S3 (SBS LG)

L1S2 (CR-AZ)

L4S3

1890

L6S3

1120 L5S3

890

L2S3

60

L1S2

Did Not Crack

L3S3

80

Oil, Asphalt and Gas

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$/G

allo

n

Asphalt Crude Oil Gasoline

Crude Oil, Gas and Asphalt

Costs

Cost Savings in Rubberized

Asphalt Materials and

Applications

1. Pave 115 miles with Rubberized Asphalt vs 100 miles with virgin Polymer for the

same $.

2. Pave almost 50% more with A-R reduced thickness design.

3. Eliminate one seal coat every twenty years (30% longer life for AR seal coats)

Business as Usual?

Sustainable Rubberized Asphalt Technologies

Sample Performance Graded Granulated Tire Rubber (GTR) Modified Asphalt

PG 76-22 GTR

Property

Original Binder

Test Method

PG 76-22TR a

Flash Point, Minimum ºC T48 230º

R. Viscosity at 135ºC, Maximum, Pa’s T316 3.0

Dynamic Shear,

Test Temp., @ 10/rad/s ºC

Minimum G*/sinδ, kPa

T315 76

1.00

RTFO Test

Mass Loss, Maximum, %

T240 1.0

RTFO Aged Binder – Test

Dynamic Shear,

Test Temp., @ 10 rad/s, ºC

Maximum G*/sinδ, kPa

T315 76

2.20

Dynamic Sheer

Test Temp. @ 10 rad/s, ºC

Maximum δ @ 2.20 kPa, Degrees

T315 Report b

80

Elastic Recovery,

Test Temp., ºC

Minimum Recovery, %

T301 25

65

PAV Aging,

Temperature, ºC

R28 100/110 c

Sample Performance Graded Granulated Tire Rubber (GTR) Modified Asphalt

PG 76-22 GTR

Property

Original Binder

Test Method

PG 76-22TR a

RTFO & PAV Aged Binder - Test

Dynamic Shear,

Test Temp., @10 rad/s, ºC

Maximum G* sinδ, kPa

T315 31

5000

Creep Stiffness,

Test Temp., ºC

Maximum S, at 60s, MPa

Minimum Slope, m-value

T313 -12

300

0.300

Notes:

a. PG-GTR binders require a minimum of 8 percent by weight Granulated Tire rubber (GTR) content,

provide a batch or weight tickets to the engineer to verify the GTR content..

b. Test temperature is the temperature at which G*/sinδ is 2.2 kPa. A graph of log G*sinδ plotted against

temperature may be used to determine the test temperature when G* sinδ is 2.2 kPa. A graph of delta (δ)

versus temperature may be used to determine delta (δ) at the temperature when G* sinδ is 2.2 kPa. The

Engineer also accepts direct measurement of delta (δ) is 2.2 kPa.

c. Use 110º C PAV Aging Temperature for Desert Climate only.

d. Solubility may be used to verify rubber content, report only

www.libertytire.com

dcarlson@libertytire.com

602-751-6039

Rubberized Asphalt