Asphalt-Rubber Information, Issues and Obstacles

Doug CarlsonExecutive Director

Rubber Pavements Association

Information, Issues and Obstacles

Dedicated to encouraging greater usage of high Dedicated to encouraging greater usage of high quality, cost effective asphalt pavements quality, cost effective asphalt pavements

containing recycled tire rubber.containing recycled tire rubber.

What is the RPA?What is the RPA?

•• Crumb Rubber ProducersCrumb Rubber Producers•• Contractors Who Use Crumb Contractors Who Use Crumb

Rubber in PavementsRubber in Pavements•• Equipment ManufacturersEquipment Manufacturers•• Consulting FirmsConsulting Firms•• Testing LaboratoriesTesting Laboratories

The RPA is a nonThe RPA is a non--profit industry association comprised ofprofit industry association comprised of::

Germany, United Kingdom, Mexico, Canada, United Germany, United Kingdom, Mexico, Canada, United States, Austria, Portugal, Saudi Arabia, Australia, States, Austria, Portugal, Saudi Arabia, Australia,

South Korea, South Africa, Netherlands and SwedenSouth Korea, South Africa, Netherlands and Sweden

Where are the RPA Where are the RPA members?members?

TECHNOLOGY TRANSFERTECHNOLOGY TRANSFERTHROUGHTHROUGH

•• SeminarsSeminars•• Field ToursField Tours•• Sponsoring ResearchSponsoring Research•• RPA NewslettersRPA Newsletters•• Publishing ReportsPublishing Reports

•• Reference LibraryReference Library•• Monitoring Tire LawsMonitoring Tire Laws•• Provide Guidance for Provide Guidance for

Agencies in Use of Agencies in Use of CRM AsphaltCRM Asphalt

Who advises the RPA?Who advises the RPA?The RPA Technical Advisory Board is made up The RPA Technical Advisory Board is made up of the nationof the nation’’s leading experts on crumb rubber s leading experts on crumb rubber

and rubber modified asphalt pavements.and rubber modified asphalt pavements.

Dr. Serji AmirkhanianDr. Serji Amirkhanian

Clemson UniversityClemson University

Dr. Rudy JiminezDr. Rudy Jiminez

University of ArizonaUniversity of Arizona

Dr. K.C. EvansDr. K.C. Evans

Odessa District, TXDOTOdessa District, TXDOT

Dr. Jon EppsDr. Jon Epps

University of Nevada, University of Nevada,

Reno, EmeritusReno, Emeritus

Dr. Kamil Kaloush,Dr. Kamil Kaloush,

Arizona State UniversityArizona State University

Dr. Jorge SousaDr. Jorge Sousa

Consulpav InternationalConsulpav International

George Way, Pavement Services Engineer, Arizona DOT Chairman

Byron Lord, Dep. Director, Office of Pavement Technology, FHWA

Doug Bernard, Director FHWA Office of Technology Applications (retired)

Mark Belshe, FNF Construction, Arizona

Gene Morris, Director, AZ Transp. Center, AZ DOT (retired)

Larry Smith, Florida DOT Materials Engineer (retired)

Anne Stonex, MacTec/Law Engineering, Phoenix

Dick Stubstad, Eres Consulting, California

Maghsoud Tahmoressi, Former Bituminous Materials Engineer, Texas DOT, President PaveTex Engineering

Jack Van Kirk, Former Caltrans Engineer, Valley Slurry Seal, CA

Joe Cano, Bureau of Indian Affairs, US Dept. of Interior

Technical Advisory Board Technical Advisory Board cont.cont.

Does RPA recommend the Does RPA recommend the use of all paving material use of all paving material

containing crumb rubber from containing crumb rubber from scrap tires?scrap tires?

•• RPA has strict criteria RPA has strict criteria for paving materials for paving materials and processes the and processes the association association recommends or recommends or promotespromotes

•• NonNon--patented, nonpatented, non--proprietary processesproprietary processes

Paving materials must be Paving materials must be proven through the following:proven through the following:

•• Extensive laboratory researchExtensive laboratory research•• Construction evaluation researchConstruction evaluation research•• Successful field performance in all climatesSuccessful field performance in all climates•• Routine use by two or more states Routine use by two or more states (std. (std.

specs)specs)

What products currently meet What products currently meet the RPA criteria?the RPA criteria?

“Asphalt-Rubber is a blend of asphalt cement, reclaimed tire rubber and certain additives, in which the rubber component is at least 15% by weight of the total blend and has reacted

in the hot asphalt cement sufficiently to cause swelling of the rubber particles.”

AsphaltAsphalt--Rubber as defined Rubber as defined by ASTM D8by ASTM D8

Benefits of A-R

• Long Term Performance• Resistance to Cracking• Reduced Thickness• Cost Savings• Reduced Wet Weather Spray• Tire Recycling• Tire Pavement Noise Reduction

Obstacles

• It doesn’t work in this state/climate.• We tried it and it didn’t work.• It can’t be recycled• The emissions are dangerous• It costs too much

Low Temperature PG Similarities

Red dots indicate areas with the same low temperature performance values

Asphalt-

Rubber

Projects

1988-2000

Good Cold Weather Performance

It Didn’t Work!

• Traditional aggregate gradations are dense with many fine stone particles.

• Rubber particles are fine.• Room must be made for the rubber.• The aggregate fines must be removed

or reduced.• Gap Grade or Open Grade mixes

Open GradedOpen Graded Gap GradedGap Graded Dense GradedDense Graded

Aggregate Gradation ComparisonAggregate Gradation Comparison

An aerial view of a portable Asphalt-RubberPlant setup at a Hotplant.

Metric Ton of MixMix Type Kgs of

AsphaltKgs of Rubber

Kgs of Stone

HMA 42 0 958

940

918

Gap Graded 48 12

Open Graded 66 16

The Most Important Factor in the Success of Asphalt-Rubber:

HEAT MANAGEMENT• Virgin Asphalt Temp: >350° F (177 C)• Binder Temperature:325 °-375° F (163–191 C)• Aggregate Temperature: <350° F (177 C)• Mix Temp. b/f Breakdown: >275° F (135 C)• Ambient/Surface Temp: >65°/85°F (18/30 C)

Emission Studies

ISTEA Mandate in 1991 provided a great quantity of data, the rubber is not

subjected to temperatures great enough to cause “rubber” emissions.

Evaluation of Exhaust Gas Emissions and Evaluation of Exhaust Gas Emissions and Worker Exposure from Asphalt Rubber Worker Exposure from Asphalt Rubber

Binders in Hot Mix Asphalt Mixtures Binders in Hot Mix Asphalt Mixtures

Kathryn OKathryn O’’C. GunkelC. Gunkel

Wildwood Environmental Engineering Wildwood Environmental Engineering Consultants, Inc.Consultants, Inc.

Michigan Department of TransportationMichigan Department of Transportation

19941994

Quantified Emissions From Seven Mixtures

• Control 1 – 85/100 Pen AC 30% RAP• Control 2 – No Rubber, No RAP• Control 3 – No Rubber, 20% RAP• RBR 1 – Wet Process, No RAP• RBR 2 – No Rubber, 20% RBR RAP• RBR 3 – Wet Process, 20% RBR RAP• RBR 4 – Dry Process, No RAP

Let’s look at these two

• Control 2 – No Rubber, No RAP• RBR 1 – Wet Process, No RAP

Operating Data/Conditions/ Measurements

Control 2 RBR 1

HMA Production Rate (tons per hour) 351 357 Dry Aggregate Rate (TPH) 330 333 Asphalt Cement Added (%) 5.75% 6.84% Materials moisture content 4.17% 5.21% Fuel Consumption (gal/hr) 655 690 Exhaust Gas Temperature (F) 311 324 Mix Temperature (F) 296 316 Sample Volume (SCF) 46.501 42.823 Sample Volume (cu. m) 1.317 1.213 Exhaust Gas Moisture (%) 27.0% 29.3% Stack Temperature (F) 260 271 Actual Exhaust Gas Flow (ACFM) 89,540 95,450 Dry Exhaust Gas Flow (DSCFM) 47,076 47,836 Dry Exhaust Gas Flow (DSCMM) 1,333 1,355

The Operating Conditions Are Similar

Continuous Emissions Measurements and Method 18 Results

Control 2 RBR 1

CO2, %, Orsat Result 5.79% 6.02% O2, %, Orsat Result 12.75% 12.10% N2, %, Orsat Result 81.46% 81.88% Carbon Dioxide (CO2) 6.00% 6.48% Oxygen (O2) 12.87% 12.18% Carbon Monoxide (CO) PPM 430.5 259.5 Nitrogen Oxides (NOx) PPM 139.3 124.4 Sulfur Dioxide (SO2) PPM 74.4 76.7 Non Methane Total Hydrocarbons (NMTHC) as Carbon PPM

225.5 183.0

Methane (CH4) as measured PPM 27.7 10.6 Methane as Carbon PPM 20.7 7.9 Total Hydrocarbons (THC) as Carbon PPM

245.1 191.3

NMTHC as Carbon PPM 225.5 183.0

The Emissions Are Similar

PAH Emissions Measurements (lbs/hr) Control 2 RBR 1 Acenaphthene 0.0018 0.0021 Acenaphthylene 0.0022 0.0026 Anthracene 0.0003 ND Benzo Anthracene 0.0002 ND Chrysene 0.0003 ND Fluoranthene 0.0030 0.0024 Fluorene 0.0051 0.0055 Naphthalene 0.0502 0.0622 Naphthalene, 2-Methyl- 0.0578 0.0788 Phenanthrene 0.0120 0.0141 Pyrene 0.0030 0.0022 Cumene 0.0056 0.0069 o-Cresol (2-Methylphenol) 0.0029 0.0011 m-/p-Cresol (3-/4-Methylphenol) 0.0052 0.0058

The Emissions Are Similar

Conclusions

• Rubber does not contribute significantly to any increase in undesirable compounds.

• The base asphalt and burner fuels will cause greater changes in emissions than rubber.

Crockford, W.W., Makunike, D., Crockford, W.W., Makunike, D., Davison, R.R., Scullion, T. and Billiter, Davison, R.R., Scullion, T. and Billiter,

T.C. T.C.

Report FHWA/TXReport FHWA/TX--95/133395/1333--1F.1F.Texas Transportation InstituteTexas Transportation Institute

May 1995May 1995

Recycling Crumb Rubber Recycling Crumb Rubber Modified Asphalt Modified Asphalt

PavementsPavements

“...the material is recyclable and that the recycled material, if properly designed and constructed, should have acceptable long-term performance.”

““...air quality does not seem to be any more severe ...air quality does not seem to be any more severe a problem than it is with conventional asphalt.a problem than it is with conventional asphalt.””

“…“…the effect of CRM on emissions may be relatively the effect of CRM on emissions may be relatively small in comparison to the effects of other small in comparison to the effects of other variables.variables.””

TTI Conclusions

Percent Cracking Arizona DOT Materials Group

0123456789

10111213

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Years

Perc

ent

Crac

king

Overlays/Inlays

AR-ACFC

New Const,Neat Asphalt

Smoothness Inches/Mile Arizona DOT Materials Group

01020304050607080

0 1 2 3 4 5 6 7 8 9 10

Years

Inch

/Mile

ACFCAR-ACFC

Arizona DOT, Materials Group, Maintenance Cost, Dollars Per Lane Mile

0200400600800

1000120014001600

0 1 2 3 4 5 6 7 8 9 10Years

$/Ln

Mile

Neat AsphaltAR-ACFC

Reduced Maintenance Costs

• Greater Durability– Thicker Film on Aggregates

• Better Aging Properties– Anti-Oxidants & UV Inhibitors in

Rubber• Resists Thermal Cracking

Significant Cost Savings vs. Total Reconstruct

Reconstruct Section: $216,675 per lane-mileResurface w/Asphalt-Rubber: $ 39,564 per lane-mile

Savings: $177,111 per lane-mile

An 82% cost savings!!!!!

*SOURCE: Los Angeles County Rubberized Asphalt Concrete Technology Center

Typical Costs of Paving Materials-Arizona DOT

Asphalt Concrete - Dense Graded (5% Binder)

Aggregate + Mix, Place, Compact = $20.00 ton

Asphalt = 8.20 ton

Total = $28.20 ton

Square yard, 1 inch thick = $1.55

Asphalt Rubber Concrete - Gap Graded (8% Binder)

Aggregate + Mix,Place, Compact = $22.00 ton

Asphalt Rubber at 8% Binder = 19.80 ton

$41.80 ton

Square yard - Inch = $2.05

Asphalt Rubber Concrete – Open Graded (10% Binder) Asphalt Concrete Aggregate + Mix, Place, Compact = $26.00 ton Asphalt Rubber = 23.00 ton Total = $49.00 ton Square yard - Inch = $2.15Other costs to be considered

– Grind and Groove (PCCP)– Cost of Project Management (Might be significant on

some projects)– Raising curbs, guard rail, sign posts, and structure.– Thickness of lifts (AC DG 4 inches, ARC GG 2 inches, AR

OGFC 1 inches)– Disposal of old tires– Tack Coats

Cost Reconsidered

Material Cost SquareYard

Inch

Typical Layer Thickness

Cost Square Yard

AC DG $1.55 4 inches $6.20

$4.10

$2.15

AR GG $2.05 2 inches

AR OGFC $2.15 1 inch

Things You Need

• DOT/Agency Champion– Bituminous Material Engineer– Pavement Design Engineer– Laboratory Supervisor

Things You Need

• Specifications– ASTM– AASHTO– Neighboring State

CRM, Binder, Aggregate

Things You Need

• Knowledge Base– Binder Design– Mix Design– Testing LabsMore likely to change aggregate gradation

due to Superpave developments

80% of failures/problems due to dense graded aggregate, 20% due to low binder content.

Things You Need

• Local Tire Processor– Beneficial use of local scrap tire generation– Scrap tire supply

Crumb Rubber -16-30 Mesh is commonly used; less than 0.01% wire, 0.5% fiber and free of other contaminants.

Things That Help

• Tire Law or Program– Loans– Grants– Production Subsidy– Economic Development

• Political Champion– Local EPA and DOT interface

• Contractors

Things to Try

• Noise Reduction– Neighborhood or community groups near

freeways– Many old PCCP need rehab

Noise Reduction 101

Quiet,

Please!

Analysis of Traffic Noise From U.S. 60 Before and After Paving With Asphalt-Rubber

www.rubberpavements.org

Han Zhu, Ph.D.

Arizona State University Civil Engineering

Douglas D. CarlsonRubber Pavements Association

Can XiaoArizona State University Civil Engineering

US 60 Noise Analysis Locations 180 meters West of KyreneUS 60 Noise Analysis Locations 180 meters West of Kyrene

US 60 BeforeUS 60 Before

US 60 Noise AnalysisUS 60 Noise Analysis

Location Before After DecreaseShoulder (15m) 79.8 72.6 7.2Soundwall (30m) 76.6 67.1 9.5Residential (120m) 51.7 45.6 6.1

62

63

64

65

66

67

68

69

Dec

ibel

s dB

Before 1 Mo After 4 Years After

1995 1995 1999

Noise Reduction After Repaving with DGAC Sacramento Co. PW

60616263646566676869

Dec

ibel

s d

B

Before 1 Mo After 16 Mos later 6 Yrs later

1993 1993 1995 1999

Noise Reduction After Repaving with A-R Sacramento Co. PW

State Tires Used in Asphalt (000s) ADOT CalTran TxDOT FDOT Totals

1995 1,150 620 475 1,625 3,870

1996 813 1,240 305 1,500 3,858

1997 1,150 700 420 1,380 3,650

1998 2,050 360 1,110 1,680 5,200

1999 1,800 1,500 433 2,955 6,688

2000 1,486 1,800 762 1,700 5,748

2001 1,500 2,100 1,366 1,600 6,566

9,949 8,320 4,871 12,440 35,580

Traditional Dense Graded Mix

A-R Open Graded Friction Course

Questions?