Crumb Rubber Modified BitumenCrumb Rubber Modified Bitumen------ Application Application vs vs SpecificationSpecification

____________________________________________________________________ValeroValero BeniciaBenicia Asphalt plant andAsphalt plant and PolyphaltPolyphalt Inc.Inc.

AMAP CONFERENCEAMAP CONFERENCE0101--2828--0303

Crumb Rubber Modified Bitumen (CRMB)

! Overview

! Current Status & Issues

! Feature & Benefit

! Specs vs Applications

What is CRMB ?What is CRMB ?

Good question … no simple answer

! Diverse recycled rubber sources! Diverse processes and applications

! Diverse opinions and perceptions

! A moving target

CRMB: An OverviewCRMB: An Overview

Rubber Aggregate(Rubber modified

hot-mix)

-Plus-Ride-Generic-Chunk

DRYBlended w. AC/Aggregate

- Other SpecialtyCrumb Rubbers(TR Disposal& Indus. Waste)

Modified Bitumen(CRMB)

- On-Site A-R

- Terminal Blend

WETBlended w. AC

ProductProcess

- McDonald

Recycled Rubber

Barriers to Market AcceptanceBarriers to Market Acceptance!! PerformancePerformance

!! Logistics Logistics

!! Economics Economics

!! EnvironmentalEnvironmental

Crumb Rubber Loading LevelCrumb Rubber Loading Level

PerformancePerformance

Logistics / Logistics / handlinghandling

Need Ease handlingNeed Ease handling

Mandates ???Mandates ???

Background:Background:! 1992 - ISTEA Mandate passed

! 1995 – Sections 1038 of ISTEA mandate repealed

Impact:Impact:! Confusion

! Industry backlash

! Significant spike in R&D, field work

Issue:Issue:! Role of environmental policy in determining engineering specifications

Market CharacteristicsMarket Characteristics!! CRMB Paving Market approaching 400,000 tonsCRMB Paving Market approaching 400,000 tons

!! Undergoing “renaissance” at presentUndergoing “renaissance” at present

!! Regions of high use limitedRegions of high use limited

!! Many Countries’ exploring optionsMany Countries’ exploring options

!! Diverse applicationsDiverse applications

CRMB Process ComparisonCRMB Process Comparison

Pumpable, ControllableHigh, varying with AC &/or TR type, %

Process Viscosity

Maintain consistentChange during storing or applying

Performance

Physical & chemical / Modified contl. phase

Physical / SwollenDispersed phase

Interaction / Nature of Modification

CompatibleProne to rapid settling

Storage Stability

15% to 20% by wet15% to 20% by wtAt the Same Loading Levels

Refinery / TerminalOn-SiteBlending Location

Advanced CRMB Advanced CRMB ProcessProcess

Conventional Conventional CRMB ProcessCRMB Process

Key ItemKey Item

Morphology of CRMAMorphology of CRMA

Advanced ProcessAdvanced Process

Conventional ProcessConventional Process

Advanced CRMA ProcessAdvanced CRMA Process

--CR Liquefied to a type of oilCR Liquefied to a type of oil: : miscible with bitumen but sacrificing CR performance offering

-- Produce Produce CRMB with -a desired feature and benefit-a performance graded product

-- Conventional Conventional CRMB process with performance uncertainty

Crumb Rubber Loading at 15 to 20% LevelCrumb Rubber Loading at 15 to 20% Level

Advanced CRMB ProcessAdvanced CRMB Process

CRMB ApplicationsCRMB Applications

Pavements! Hot Mix Asphalt

Hot Applied Surface Treatments! Crack Fillers / Joint Sealers! Bridge Deck Coatings! Tack Coats! Emulsions

Other Markets! Waterproofing! Membranes! Coatings

!

CRMB Features & BenefitCRMB Features & BenefitPerformance:Performance:!! Increased rutting resistance at elevated temperatures! Improved fatigue resistance at intermediate temperatures! Reduced thermal cracking! High degree of adhesivity and elastic behavior

Logistics:Logistics:!! Consistent “endConsistent “end--point” viscositypoint” viscosity!! Excellent storage and thermal (performance) stabilityExcellent storage and thermal (performance) stability!! Homogeneous and pumpableHomogeneous and pumpable

Field:Field:!! Straightforward compaction! Lower temperatures reduce fuming and odors

Role of CRMB in Its Application

Material Selection (CRMB)

Design Construction

End Application and Durability

CRMB Specification Development

" Secure the Role of CRMB in its Application

" Position it into its End Application" Capture its Features and Benefits

“Product” Specification Types“Product” Specification Types! Functional Specification

-describe end use

-risk of performance is on the seller

! Performance Specification

-specify measurable capabilities

-risk of performance is on the seller

! Detailed (or “Design”) Specification

-quantitative, physical or Chemical description

-industry or commercial standard

-risk of performance is on the buyer

CRMB SpecificationCRMB Specification!A Detailed (or “Design”) Specification

-quantitative, physical or Chemical description

-industry or commercial standard

-sampling defined

! Minimize Risk on Buyer/User Side

-understand the application

-select relevant parameters as close as possible

-address all major distresses during the application

Application vs SpecificationApplication vs Specification! Pavements (Specifications)! Hot Mix Asphalt (MB, MAC-10TR, PG-TR etc)! Hot Applied Seal Coats (AC15-5TR)! Crack Fillers / Joint Sealers ! Bridge Deck Coatings !Tack Coats

CRMB Specification for Hot mix

An Advanced CRMB Spec must address

• Rutting

• Fatigue

• Thermal Cracking

• Aging

• CRMB Stability

Pavement Rutting

Critical Factors

" Traffic Frequency

" Traffic Load & Speed

" Temperature Distribution

" Traffic Accumulation Rate

Parameters to Address Rutting in CRMB Specs

• North America: PG/PG+ & MB: Dynamic Modulus ( G*/Sin δ )MAC-10TR : Absolute Viscosity @ 60°C

Pen & S.P.

• AustraliaAB Grade: Consistency @ 60°C and SP

Pavement Fatigue

" Critical Temperature

" Aging

" Traffic Load & Speed

" Traffic Rate & Accumulation

" Structure (Strain level)

Critical Factors

Parameters to Address Fatigue in CRMB Specs • North America: PG-TR: Dynamic Viscosity (η* ) on PAV(Tex-539-C0): ER @ 50FMB: SSD: (δ@10rad/s - δ@1rad/s)

SSV: (η*@10rad/s-η*@1rad/s)

• AustraliaAB Grade: Torsional Recovery @ 25 °C

Pavement Thermal Cracking

" Cooling Rate

" Aging

" Pavement Temperature

" Temperature Cycle

Critical Factors

Parameters to Address Cracking in CRMB Specs

• North America: PG-TR & MB: Creep Stiffness & Rate (on PVA)MAC-10TR: PEN @ 4°C (RTFO)

• AustraliaAB Grade: Stiffness @ 15°C

CRMB Storage Issues

• CRMB Degradation" CR Separation

Critical Factors

• Storage Temperature

• Storage Time

• CR Type

• CR & Asphalt Interaction

• Process Type

Stability in CRMB Specs

" Phase Separation well Addressed-Storage: 163°C or 180°C for 48 or 72 hours-Measure: Stiffness Difference in Top & Bottom

Advanced CRMB SpecAdvanced CRMB SpecProposed for Hot MixProposed for Hot Mix

PropertyAASHTOMethod

PGCR15(76-22)

RAC (70-22)

PGCR15 (70-28)

Original CRMB (at 18% at least CR load level)

Flash Point, min., °C T 48 230 230 230

Rotational Viscosity (RV) @ 135 °CCp, max.

TP 48 3,000 3,000 3,000

Dynamic Shear RheometerG*/Sin Delta, kPa, min.

TP 5 1.00at 76°C

1.00at 70°C

1.00at 70°C

Elastic Recovery (ER), 25°C elongation @ 10 cm, % min.

ASTM D-113

50 50 50

CRMB Stored @ 163°C after 48 hrs

Difference in R & Bfrom Top and Bottom, °C, max

ASTM-D36 2 2 2

Rotational Viscosity (RV) @ 135 °CCp

TP 48 report report report

RV Variation +% 20 20 20

Advanced CRMB SpecAdvanced CRMB SpecProposed for Hot MixProposed for Hot Mix ------ Contl.Contl.

PropertyAASHTOMethod

PGCR15(76-22)

RAC (70-22)

PG CR15(70-28)

CRMB RTFO Residue

Mass loss, %, min. 1.00 1.00 1.00

Dynamic Shear RheometerG*/Sin Delta, kPa, min.

TP 5 1.50at 76°C

1.50at 70°C

1.50at 70°C

Elastic Recovery (ER), 25°C elongation @ 10 cm, % min.

ASTM D-113

report report report

ER, Retention, %, min 80 80 80

CRMB PAV Residue (100°C)

Creep Stiffness (S)Mpa @ 300 MPa, max.

TP -12 °C -12 °C -18 °C

Slope (m) 0.300, min TP -12 °C -12 °C -18 °C

Concluding Remarks

• Properties Measured by an Advanced CRMB Spec Should Address all Critical Factors Causing Distresses in a Specific Application • Current CRMB Specs do not Relate Closely to Real Pavement Performance• Quite few Discrepancies of Current CRMB Specs exist in their Parameters to Predict the Performance

• CRMB Specs Should Take CRMB Storage/Performance Stability during Handling into Account

Thank You