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?