c. thodesen, s. biro: using crumb rubber modifier to meet us demand in high performance asphalt

8/14/2019 C. Thodesen, S. Biro: Using Crumb Rubber Modifier to meet US Demand in High Performance Asphalt

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Using Crumb Rubber

Modifier to meet USDemand in High

Performance Asphalt

Dr. Carl Thodesen

and

Dr. Szabolcs Biro


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Introduction

Continuously analyzing market and needs.

Predicting future trends

Remedy problems.

Developing new products and formulas tosatisfy all needs (climate, country) on themost efficient ways.


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Current Market


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Current Market


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Current Market


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Current Market


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Current market andsituation

Large part of the marketaccessible only through modifier.

SBS most widely used modifier.

Prudent planners should beworking on the basis that theavailability of SBS polymer will

be tight in the immediate future SBS Polymer supply outlook (August 6. 2008)

Different countries have differentraw materials.


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Different solutions

Different countries and climaticzones require different propertymaterials.

There is no universal solution.

Maximum flexibility in

production is required.


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Recommendations Adopt appropriate modification

depending on climate (can bedifferent in one country).


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Potential Issues

SBS supply beginning to tighten

Environmental legislation

promoting use of recycledresources

Price variations causing state

agencies to consider otheroptions


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AMAP Recommended

Solutions Reacted Ethylene Terpolymer (Elvaloy)modified binder.

Ethyl Vinyl Acetate (EVA) modified

binder. Polyphosphoric Acid (PPA) + SBS

modified binder.

Crumb Rubber (CRM) modified binder.

Hybridized binders (SBS + CRM).


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Elasticity

Time, s

0 10 20 30 40 50 60

Strain,

%

0

5

10

15

20

CRM-AZ

Elvaloy

EVA

SBS+CRMSBS+PPA

SBS


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Our findings

Crumb rubber modified bindercan be both technically andeconomically a good substituentfor SBS modified bitumens.


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CRM Binder

Crumb rubber modified bindersare NOT the same.

They can satisfy differentstandards/requirements bychanging the productionparameters and raw materials(bitumen, rubber, additives).


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CRM Binder vs. CRM binder

Temperature, oC

0 20 40 60 80 100

E

lasticityindicator(tan

)

0

1

2

3

4

5

6

7

8

AZ

CA

FL

SC

TX


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Temperature, oC

0 20 40 60 80 100Ruttingpotentialindic

ator(G*/sin,

Pa)

1e+2

1e+3

1e+4

1e+5

1e+6

1e+7 AZ

CA

FL

SC

TX


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Vehicle speed indicator (Frequency, rad/s)

0.01 0.1 1 10 100 1000Ruttingpotentialindic

ator(G*/sin,

Pa)

1e+1

1e+2

1e+3

1e+4

1e+5

1e+6

AZ

CA

FL

SC

TXNeat binder


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Properties of CRM

binders Not just the rubber concentration,gradation, but chemicalcomposition has an effect.

Importance of asphalt chemicalcomposition.

CRM binder formulation is

needed to obtain the bestresult.


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CRM Binder

We recall that PG 76 and PG 70are the most used binders in theUS.

Crumb rubber can be used toproduce these binders.

Many specifications achievedwith SBS are possible usingcrumb rubber.


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SBS vs. CRM Binder

New generation of blendingequipment are needed toprovide maximum productionflexibility.


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Conclusions

Polymer modified binder a growingindustry.

Reduced lifecycle cost makes this

binder more attractive option fordepartments of transportation.

SBS has been market leader to date.

Butadiene supply issues couldbecome an issue.


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Conclusions

Crumb rubber is proven to be agood solution for substituting SBS.

There are significant differencesbetween the performance ofcrumb rubber modified binders.

There is no universal solution,

binder formulation is needed.


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Conclusions

Engineering expertise.

High flexibility in production is

required. Right selection of raw materials.

Crumb rubber producers could

have an effect on better, andconstant quality.

c. thodesen, s. biro: using crumb rubber modifier to meet us demand in high performance asphalt

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