Societal Issues

• Economy• Transportation fuel pricing• Job creation• Infrastructure funding & renewal• Energy independence• Climate change

Asphalt IndustryBackground & Challenges

• Approximately 68% of GDP utilizes our transportation systems

• About 90% of Nation’s paved highways use asphalt– Asphalt pavements and composite pavements– Maintenance applications (patching, crack sealing, surface

treatments)

• Asphalt is derived from crude petroleum

• Refinery modifications has removed asphalt from the market to produce more transportation fuels

Impacts of Higher Crude Oil Prices

• Higher asphalt & fuel prices reduces the number of infrastructure projects

• Fewer miles driven– 50 billion fewer miles from November 2007 to May 2008– 11 billion fewer comparing March 2007 to March 2008 (4.3% decrease)– 15 billion fewer miles comparing August 2007 to August 2008 (5.6% decrease)

• Decrease in highway tax revenue

• Less asphalt polymers available due to reduction in tire manufacturing & reduction in butadiene production

• Less money for infrastructure projects

Asphalt Industry Market

Colorado• 9.0 million tons of hot mix asphalt ($540 million annually)

• 450,000 liquid tons of asphalt ($320 million annually- net import to Colorado)

• 68 stationary & 8 mobile hot mix asphalts plants

• Industry employs about 7,500 consisting of trades people, engineers, and financial & banking specialists

Nationally• 500 million tons of hot mix asphalt ($30 billion annually)

• 30 million liquid tons of asphalt ($21 billion annually)

• ~4,000 stationary & 500 mobile hot mix asphalt plants

Bio-economy and Transportation Link

• Market share of bio-energy will become greater percentage of overall energy sector– 2007 Energy Title mandates 36 billion gallons of ethanol

be sold in U.S. by 2022; 21 billion gallons of which must be produced from cellulosic feedstocks

– fast pyrolysis is one of the systems that will likely be deployed to produce cellulosic biofuels

– bio-oil produced from fast pyrolysis shows great promise as an asphalt material

• Solutions for utilizing bio-energy co-products exist in asphalt industry

Fast Pyrolysis

Rapid thermal decomposition of organic compounds in the absence of oxygen to produce gas, char, and liquids

Biomass

Monomers/Isomers

Low Mol.Wt SpeciesRing-opened Chains

H+

H+

M+ M+

AerosolsHigh MW Species

Gases/Vapors

Thermo-mechanical

Ejection

Vaporization

Molten Biomass

T ~ 430oC(dT/dt)→∞

CO + H2

Synthesis GasReforming

TM+

Volatile Products

M+ : Catalyzed by Alkaline CationsH+ : Catalyzed by AcidsTM+ : Catalyzed by Zero Valent Transition Metals

(Observed at very high heating rates)

Oligomers

Fast Pyrolysis Production

Fundamental Studies with Micropyrolyzer and GC/MS

He

Capillary Separation Column

Gas Chromatograph (GC)

Mass Spectrometer

(MS)

FeedstockPyrolyzer

~ 500 μg

GC/MS Analysis of Feedstock Materials

Oak Wood

Switch Grass

Corn Stover

GC/MS Analysis of ESP Fractions

Oak Wood

Switch Grass

Corn Stover

Characteristics of Fractionated Bio-Oil

Property Cond. 1 Cond. 2 Cond. 3 Cond. 4 ESP

Fraction of total oil (wt%)pHViscosity @40ºC (cSt)Lignin Content (wt%)Water Content (wt%)C/H/O Molar Ratio

6-

SolidHighLow

1/1.2/ 0.5

223.5149329.3

1/ 1.6/ 0.6

372.72.25.046

1/ 2.5 / 2

152.52.62.646

1/ 2.5 /1.5

203.3543503.3

1/1.5/ 0.5

Fast Pyrolysis Products

• Biomass pyrolyzed to bio-oil• Bio-oil fractions converted to renewable fuel, asphalt,

and other products

Pyrolyzer

Sugars Phenols Acids

Fuel Asphalt Co-Products

Biomass

Fast Pyrolysis

• Rapid thermal decomposition of organic compounds in the absence of oxygen to produce liquids, char, and gas– Small particles: 1 - 3 mm– Short residence times: 0.5 - 2 s– Moderate temperatures (400-500 oC)– Rapid quenching at the end of the

process

– Typical yieldsOil: 60 - 70%Char: 12 -15%Gas: 13 - 25%

Nature, Vol. 442, 10 Aug 2006

Bio-char: Soil amendment and carbon sequestration agent

Ca

rbon

Sto

red

(lb

/acr

e/y

r)Greenhouse gases reduced by carbon

storage in agricultural soils

Char from pyrolyzing one-half of corn stover

Greenhouse Gas Emission Comparison

• Bio-oil is a closed system with greenhouse gases (GHG) sequestered

• Crude refinery products are about 165lbs (0.083 tons) of GHG per ton of product (asphalt)

• Cement production is 0.7 tons GHG per ton of cement

Experimental Plan

• Three asphalt binders– 1 local binder (1 polymer-modified, 1 neat binder)– 2 well known binders (AAD-1 & AAM-1)

• Three experimental bio-oil fractions– Corn Stover– Oak Wood– Switch Grass

• Each asphalt mixed with each lignin sample at 3, 6, and 9 percent by weight

• Evaluate rheological properties and determine Tc and performance grade of each blend

Performance Testing

1. Blend asphalt and 1. Blend asphalt and lignin in a high speedlignin in a high speedshear mill at 145shear mill at 145°C °C for 15 minutesfor 15 minutes

2. Evaluate high-temperature2. Evaluate high-temperaturerheological properties of rheological properties of unaged blends with a DSR unaged blends with a DSR

3. Short-term age 3. Short-term age asphalt/lignin asphalt/lignin blends with a RTFOblends with a RTFO

5. Long-term age 5. Long-term age asphalt/lignin asphalt/lignin blends with a PAVblends with a PAV

4. Evaluate high-temperature4. Evaluate high-temperaturerheological properties of RTFOrheological properties of RTFOaged blends with a DSR aged blends with a DSR

6. Evaluate inter-temperature6. Evaluate inter-temperaturerheological properties of PAVrheological properties of PAVaged blends with a DSR aged blends with a DSR

7. Evaluate low-temperature7. Evaluate low-temperaturerheological properties of rheological properties of unaged blends with a BBRunaged blends with a BBR

8. Calculate8. Calculatecontinuous performance continuous performance grade of mixturesgrade of mixtures

9. Compare results of 9. Compare results of different asphalt/bio oildifferent asphalt/bio oilblendsblends

50.0

52.0

54.0

56.0

58.0

60.0

62.0

64.0

66.0

68.0

70.0

No

ne

Co

rn S

tove

r

Oa

kwo

od

Sw

itch

gra

ss

Co

rn S

tove

r

Oa

kwo

od

Sw

itch

gra

ss

Co

rn S

tove

r

Oa

kwo

od

Sw

itch

gra

ss

3 3 3 6 6 6 9 9 9

Product Type and Percentage

Un

aged

Hig

h T

c

AAD-1

AAM-1

LPMB

60.0

62.0

64.0

66.0

68.0

70.0

72.0

74.0

76.0

78.0

80.0

No

ne

Co

rn S

tove

r

Oa

kwo

od

Sw

itch

gra

ss

Co

rn S

tove

r

Oa

kwo

od

Sw

itch

gra

ss

Co

rn S

tove

r

Oa

kwo

od

Sw

itch

gra

ss

3 3 3 6 6 6 9 9 9

Product Type and Percentage

RT

FO

Ag

ed H

igh

Tc

AAD-1

AAM-1

LPMB

15.0

16.0

17.0

18.0

19.0

20.0

21.0

22.0

23.0

24.0

No

ne

Co

rn S

tove

r

Oa

kwo

od

Sw

itch

gra

ss

Co

rn S

tove

r

Oa

kwo

od

Sw

itch

gra

ss

Co

rn S

tove

r

Oa

kwo

od

Sw

itch

gra

ss

3 3 3 6 6 6 9 9 9

Product Type and Percentage

Fat

igu

e T

c

AAD-1

AAM-1

LPMB

Product Type and Percentage

-26.0

-24.0

-22.0

-20.0

-18.0

-16.0

-14.0

-12.0

-10.0

No

ne

Co

rn S

tove

r

Oa

kwo

od

Sw

itch

gra

ss

Co

rn S

tove

r

Oa

kwo

od

Sw

itch

gra

ss

Co

rn S

tove

r

Oa

kwo

od

Sw

itch

gra

ss

3 3 3 6 6 6 9 9 9

Lo

w T

c AAD-1

AAM-1

LPMB

70.0

72.0

74.0

76.0

78.0

80.0

82.0

84.0

86.0

88.0

90.0

No

ne

Co

rn S

tove

r

Oa

kwo

od

Sw

itch

gra

ss

Co

rn S

tove

r

Oa

kwo

od

Sw

itch

gra

ss

Co

rn S

tove

r

Oa

kwo

od

Sw

itch

gra

ss

3 3 3 6 6 6 9 9 9

Product Type and Percentage

Gra

de

Ran

ge

- U

nag

ed

AAD-1

AAM-1

LPMB

70.0

75.0

80.0

85.0

90.0

95.0

100.0

No

ne

Co

rn S

tove

r

Oa

kwo

od

Sw

itch

gra

ss

Co

rn S

tove

r

Oa

kwo

od

Sw

itch

gra

ss

Co

rn S

tove

r

Oa

kwo

od

Sw

itch

gra

ss

3 3 3 6 6 6 9 9 9

Product Type and Percentage

Gra

de

Ran

ge

- A

ged

AAD-1

AAM-1

LPMB

High Temperature Tc Means Testing

ComparisonDifference in Means (ºC)

LSD95%

Confidence

Tukey95%

Confidence

Bonferoni95%

Confidence

Binder TypeAAD – AAM -1.39 Yes Yes YesAAD – LPMB -3.70 Yes Yes Yes

AAM – LPMB -2.31 Yes Yes Yes

Bio Oil Content

0 – 3 -1.84 No No No0 – 6 -2.36 Yes No No

0 – 9 -2.74 Yes Yes Yes3 – 6 -0.52 No No No3 – 9 -0.90 No No No

6 – 9 -0.38 No No No

Bio Oil Source

None – Corn Stover -1.21 No No NoNone – Oak Wood -5.45 Yes Yes Yes

None – Switch Grass -0.85 No No No

Corn Stover – Oak Wood -4.23 Yes Yes YesCorn Stover – Switch Grass +0.36 No No No

Oak Wood – Switch Grass +4.59 Yes Yes Yes

Low Temperature Tc Means Testing

ComparisonDifference in Means (ºC)

LSD95%

Confidence

Tukey95%

Confidence

Bonferoni95%

Confidence

Binder TypeAAD – AAM -7.72 Yes Yes YesAAD – LPMB -1.30 Yes Yes YesAAM – LPMB +6.42 Yes Yes Yes

Bio Oil Content

0 – 3 -2.20 Yes Yes Yes0 – 6 -3.23 Yes Yes Yes0 – 9 -3.43 Yes Yes Yes3 – 6 -1.03 Yes Yes Yes3 – 9 -1.23 Yes Yes Yes6 – 9 -0.20 No No No

Bio Oil Source

None – Corn Stover -3.66 Yes Yes YesNone – Oak Wood -4.25 Yes Yes Yes

None – Switch Grass -1.06 Yes No NoCorn Stover – Oak Wood -0.60 No No No

Corn Stover – Switch Grass +2.59 Yes Yes YesOak Wood – Switch Grass +3.19 Yes Yes Yes

Summary of Asphalt/Bio-oil Research

• The addition of lignin containing co-products to asphalt binders causes a stiffening effect– Binder effects– Biomass Source of Lignin– Amount of Lignin

• The stiffening effect increases the high, int., and low critical temperatures of the asphalt/lignin blends

• The high temperatures are increased more than the low temperatures

• Grade ranges in some combinations are increased by one grade (6ºC) and in other combinations no effects

Development of a Bio Binder

• Can bio oil fractions be upgraded to produce an asphalt binder replacement?

• If so, how is this accomplished?• Will the technology be turn key with existing

asphalt industry production & construction processes?

• What is the performance of the bio binder?• How do we specify bio binder quality?

Development of “Reaction” Curves

• Understand that bio oil properties can change with heating

• Assist with formulating bio binders

Set of “Reaction” Curves

0

1000

2000

3000

4000

5000

6000

0 2 4 6 8 10

Time (hrs)

Vis

cosi

ty (cP

)) .

CS @ 135 C

CS @ 125 C

Examining Polyethylene Polymer Effects

0

200

400

600

800

1000

1200

1400

0 2 4 6 8 10Time (hrs)

Vis

cosi

ty (cP

) . OF+2%617_135

OF+2%680_135

OF+2%9_135

Dynamic Shear Rheometer Testing

• Created bio binder grades of 52 and 58ºC based upon unaged samples

• Mixing Temperature of 105ºC• What is the appropriate short term aging

protocol?• What is the appropriate long term aging

protocol?

What makes bio-oil attractive for use in asphalt industry?

• Replacement of asphalt binder at a lower price

• Can be used as an asphalt anti-oxidant additive to increase asphalt pavement life

• Can lower asphalt plant production temperatures– Lower plant operating costs (fuel

consumption)– Lower production temperatures

reduces greenhouse gas production• Bio-oil is renewable

Research Questions

• Specification criteria• Field handling & constructability• Field performance

Full scale pilot plant under construction and anticipate field trials 2009 construction season

Benefits to United States

• Economic development and job creation

• Lower petroleum based product pricing by creating alternatives

• Sustainable transportation inputs with lower GHG

• Lower infrastructure costs- construction, pavements and maintenance activities

• Petroleum independence

Acknowledgements

• Iowa Department of Transportation– www.iowadot.gov/operationsresearch/default.html

• Iowa Energy Center– www.energy.iastate.edu

Thank You!&

Questions?