Life Cycle Assessment for Pavements with Low Rolling

Resistance

Reducing CO2 emissions through reduced rolling resistance TRB 2012

John Harvey - UC Davis Alissa Kendall - UC Davis Ting Wang - UC Davis In-Sung Lee - UC Davis Eul-Bum Lee, UC Berkeley Changmo Kim, UC Davis

Funding from:

Caltrans/UC Pavement Research

Center and UC Multi-Campus

Research Projects Initiative

Work presented is part of Miriam

• SP3 sub-task: Pavement LCA

• Swedish case studies done by VTI

• ZAG Slovenia evaluating road

network

Paper on this work under review

Journal of Cleaner Production

Report to be submitted to

Caltrans in March, 2012

The Pavement Life Cycle

Materials

End-of-Life

Maintenance &

Rehabilitation

Use

Construction

Materials

extraction and

production

Transportation

Onsite

equipment - Carbonation

- Lighting

- Heat Island

- Rolling resistance

- Leachate

Traffic

delay

A framework for analysis of policy cost-effectiveness

• Prioritizing Climate Change Mitigation Alternatives: Comparing Transportation Technologies to Options in Other Sectors

• Lutsey, N. (2008) Institute of Transportation Studies, University of California, Davis, Research Report UCD-ITS-RR-08-15

Supply Curve

• Compare keeping pavement smooth with:

• 1. Reduce vehicle-miles traveled; 2. Improve fleet fuel efficiency; 3. Reduce carbon content of fuel

Initial cost

Net costs =

initial cost +

direct

energy

saving

benefits

Bang for your buck metric:

$/ton CO2e vs CO2e reduction

Objectives of PPRC 4.26 Project

• Develop LCA model for state highway and local road networks – Initial models using available data sources

– Update as develop regional databases

• Use model to answer questions regarding GHG ($/ton CO2e) and fuel use (net reductions): – Rolling resistance (Roughness and macro-texture)

– Where to use in-place, plant, secondary recycling considering transportation costs, local materials

– Design life

– Alternative rehabilitation strategies

Basic Approach by UCPRC

• Divide network into categories (factorial)

• Apply factorial case studies results to network

• Sensitivity analyses

– Rolling resistance (smoothness and texture) for MIRIAM

– Materials (type, producing method, etc.)

– Hauling distance

– Traffic levels and congestion

– Traffic closure during construction

– Fleet composition (new vehicle technologies)

Constraint during model development

• Asphalt stays asphalt

• Concrete stays concrete

• Obtain industry critique with fewer commercial implications – (exc. RHMA vs HMA,

PCC vs CSA cement)

• Afterward, consider surface type change – Within LCCA framework

Factorial for LCA for California State and Local Networks

Factorials Possible Value

Road type Rural road; urban road

Road grades Flat road; mountainous road

Road access type Restricted access; unrestricted access

Traffic level Different levels of AADT and AADTT,

categorized

Pavement surface type

Asphalt pavement; cement concrete

pavement

Pavement surface characteristics

Different levels of IRI and MPD,

categorized

Treatment Different pavement treatment options

Models: Materials and construction

• Materials production and plant emissions: – Existing databases and studies

• Off-Road equipment – OFFROAD: California’s off-road equipment emission

inventory • On-Road equipment

– EMFAC: California’s on-road vehicles emission inventory

• Equipment and hours – CA4PRS: Caltrans construction schedule analysis

tool • Road user delay

– CA4PRS (not yet implemented)

Case Study 1 (KER-5): Asphalt overlay on rural/flat freeway

10 mile (16 km) segment in need of

rehab

Rural freeway

2 lanes, southbound

AADT: 34,000; ~35% trucks

Passenger Trucks

Inner Lane 77% 9%

Outer Lane 23% 91%

Compare:

- Do Nothing

-10 year rehab

-HMA, RHMA

Construction Scenarios: KER-5

HMA Type

Design life

Treatment Cross Section Smoothness

HMA 10 Years Mill & Overlay

45 mm (0.15’) Mill + 75 mm (0.25’) HMA with 15% RAP

Smooth Rehab

Less smooth Rehab

RHMA 10 years Mill & Overlay

30 mm (0.1’) Mill + 45 mm (0.15’) RHMA

Smooth Rehab

Less smooth Rehab

KER-5: Energy in Use Phase with 0 & 3% Traffic Growth

2.0E+7

2.2E+7

2.4E+7

2.6E+7

2.8E+7

3.0E+7

6.5E+8

7.0E+8

7.5E+8

8.0E+8

8.5E+8

9.0E+8

9.5E+8

1.0E+9

2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021

Eq

uiv

ale

nt

Ga

soli

ne (

L)

To

tal E

nerg

y (

MJ

)

Year

3% Traffic growth + Do Nothing + No fuel economy improvement

3% Traffic growth + Do Nothing + Fuel economy improvement

0% Traffic growth + Do Nothing + Fuel economy improvement

0% Traffic growth + Initial IRI=1.67 + Fuel economy improvement

0% Traffic growth + Initial IRI=1 + Fuel economy improvement

-1.6E+6

-6.3E+4

1.4E+6

2.9E+6

4.4E+6

5.9E+6

7.4E+6

-5.0E+7

0.0E+0

5.0E+7

1.0E+8

1.5E+8

2.0E+8

2.5E+8

Feedstock Energy Material Production

Construction Use

Eq

uiv

ale

nt

Gaso

lin

e (

L)

Tota

l E

nerg

y S

avin

g C

om

pa

red

to D

o N

oth

ing

(MJ

)

Phase

3% Traffic growth: Smooth Rehab compared to Do Nothing

3% Traffic growth: Less Smooth Rehab compared to Do Nothing

0% Traffic growth: Smooth Rehab compared to Do Nothing

0% Traffic growth: Less Smooth Rehab compared to Do Nothing

KER-5 (RHMA): 10-year life cycle energy savings compared to “Do Nothing”

USLCI Athena

Stripple Ecoinvent

0

-1.6E+6

-6.3E+4

1.4E+6

2.9E+6

4.4E+6

5.9E+6

7.4E+6

-5.0E+7

0.0E+0

5.0E+7

1.0E+8

1.5E+8

2.0E+8

2.5E+8

2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022

Eq

uiv

ale

nt

Gaso

lin

e (

L)

Cu

mm

ula

tive E

nerg

y S

avin

g C

om

pare

d t

o

Do N

oth

ing

(M

J)

Year

3% Traffic growth: Smooth Rehab compared to Do Nothing

3% Traffic growth: Less Smooth Rehab compared to Do Nothing

0% Traffic growth: Smooth Rehab compared to Do Nothing

0% Traffic growth: Less Smooth Rehab compared to Do Nothing

KER-5 (RHMA): Cumulative life cycle energy compared to “Do Nothing”

Construction

0

Case Study 2 (LA-5): Concrete CPR B on rural/flat freeway

10 mile (16 km) segment in need of rehab

Rural freeway

4 lanes, southbound

AADT: ~80,000; ~25% trucks

Cars Trucks IRI Lane 1 (Inner) 38% 0.2% 3 Lane 2 34% 8% 3 Lane 3 16% 42% 3.5 Lane 4 (Outer) 13% 49% 4

Compare:

- Do Nothing

- 10 year CPR B

-Type III, CSA cement

Construction Scenario (LA-5)

Treatment Design life

Material Smoothness

CPR B with 3% slab replacement and grinding the entire lane

10 yrs

Type III Rapid Strength Cement (3.2 Mpa in 4 hours)

Smooth Rehab (-2σ)

Medium Smooth Rehab (mean)

Less Smooth Rehab (+2σ)

Calcium Sulpho-Aluminate (CSA) Cement (2.8Mpa in 4 hours)

Smooth Rehab (-2σ)

Medium Smooth Rehab (mean)

Less Smooth Rehab (+2σ)

-1.6E+6

3.4E+6

8.4E+6

1.3E+7

1.8E+7

-5.0E+7

5.0E+7

1.5E+8

2.5E+8

3.5E+8

4.5E+8

5.5E+8

6.5E+8

2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022

Eq

uiv

ale

nt G

aso

lin

e (L

)

Cu

mm

ula

tiv

e E

ner

gy

Sa

vin

g C

om

pa

red

to

Do

No

thin

g (M

J)

Year

3% Traffic growth: Smooth Rehab compared to Do Nothing

3% Traffic growth: Medium Smooth Rehab compared to Do Nothing

3% Traffic growth: Less Smooth Rehab compared to Do Nothing

0% Traffic growth: Smooth Rehab compared to Do Nothing

0% Traffic growth: Medium Smooth Rehab compared to Do Nothing

0% Traffic growth: Less Smooth Rehab compared to Do Nothing

LA-5 (Type III PCC): Cumulative life cycle energy savings compared to “Do Nothing”

Construction

Case Study 3 (BUT-70): Asphalt overlay on rural/flat highway

5 mile (8 km) segment in need of rehab

Rural highway

2 lanes, westbound

AADT: 3,200; ~15% trucks

Cars Trucks IRI

Lane 1 (Inner) 61% 8% 3.8

Lane 2 39% 92% 3

Compare:

- Do Nothing

-10 year rehab

-HMA, RHMA

-4.7E+5

-2.7E+5

-6.9E+4

1.3E+5

3.3E+5

-1.5E+7

-1.0E+7

-5.0E+6

0.0E+0

5.0E+6

1.0E+7

1.5E+7

2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022

Eq

uiv

ale

nt G

aso

lin

e (L

)

Cu

mm

ula

tiv

e E

ner

gy

Sa

vin

g C

om

pa

red

to

Do

No

thin

g (M

J)

Year

3% Traffic growth: Smooth Rehab compared to Do Nothing

3% Traffic growth: Less Smooth Rehab compared to Do Nothing

0% Traffic growth: Smooth Rehab compared to Do Nothing

0% Traffic growth: Less Smooth Rehab compared to Do Nothing

BUT-70 (RHMA): Cumulative life cycle energy savings compared to “Do Nothing”

Construction

0

Case Study 4 (IMP-86): Concrete CPR B on rural/flat highway

5 mile (16 km) segment in need of rehab

Rural highway

2 lanes, southbound

AADT: ~11,200; ~29% trucks

Cars Trucks IRI Lane 1 (Inner) 76% 8% 2.5 Lane 2 24% 92% 2.7

Compare:

- Do Nothing

- 10 year CPR B

-Type III, CSA cement

-3.1E+5

-6.3E+4

1.9E+5

4.4E+5

6.9E+5

9.4E+5

1.2E+6

-1.0E+7

0.0E+0

1.0E+7

2.0E+7

3.0E+7

4.0E+7

2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022

Eq

uiv

ale

nt G

aso

lin

e (L

)

Cu

mm

ula

tiv

e E

ner

gy

Sa

vin

g C

om

pa

red

to

Do

No

thin

g (M

J)

Year

3% Traffic growth: Smooth Rehab compared to Do Nothing

3% Traffic growth: Medium Smooth Rehab compared to Do Nothing

3% Traffic growth: Less Smooth Rehab compared to Do Nothing

0% Traffic growth: Smooth Rehab compared to Do Nothing

0% Traffic growth: Medium Smooth Rehab compared to Do Nothing

0% Traffic growth: Less Smooth Rehab compared to Do Nothing

IMP-86 (Type III PCC): Cumulative life cycle energy savings compared to “Do Nothing”

Construction

Conclusions

• LCA model is powerful tool to estimate net energy use and GHG from maintenance and rehabilitation activities

• Case studies to date demonstrate potential for high net energy/GHG savings on high-volume routes from improvements in roughness and texture (asphalt)

• Construction quality of smoothness critical

Next Steps • Complete work with California cement and

asphalt industries on inventories

• Develop Use phase models for congested traffic

• Complete case studies and sensitivity for factorial

• Include results in Caltrans smoothness specs

• Implement into Caltrans policy

– Initial GHG equation for pavement treatments being implemented in PMS

Questions?