Life cycle assessment (LCA)

• LCA can provide quantities– A protocol to assess the environmental, economic, and

social impacts of an industrial system. • The life cycle of the industrial system extends from cradle-to-grave: from

materials acquisition and production, through manufacturing, system use and maintenance, and finally through the end of the system’s life.

1

oil extraction

Aggregate Quarry

transport refinery transport

transport

placement transport

emissions waste hazardouswaste

other outputs

water fuel

other inputs

hma plant

An example of LCA processes, inputs and outputs to consider for

HMA paving.

For a given unit of production (e.g., 1 lane-mile of pavement) a typical LCA gives a range of outputs.

• Amount of materials used (tonnes)• Total energy use (MJ)• Water consumption (kg)• Emissions

– Global warming potential (tonnes of CO2 equivalent)– Nitrogen oxides – NOx (kg)– Sulfur dioxide – SO2 (kg)

– Particulate matter – PM10 (kg)– Carbon Monoxide – CO (kg)

• Toxic things– Human toxicity potential – Mercury – Hg (g)– Lead – Pb (g)– Hazardous waste (kg)

Things people always argue about when looking at LCA data.

• Functional unit definition– Structural design– Materials makeup

• Data sources– Asphalt in the mix– Lack of good data (especially for HMA options)– Non-specific data

• Life cycle– Number and timing of rehabilitation options– Pavement condition

2” lift of SMA

3” lift of ½” Superpave

3” lift of ½” Superpave

HMA

3” lift of ½” Superpave2” lift of ½” Superpave

10” of aggregate base(multiple lifts)

Subbase

4” lift of ¾” Superpave

PCC

13” PCC

Subbase

6” lift of CSTC

EXISTING PAVEMENT

9” PCC

Subbase

CSOL

Subbase

9” PCCCracked and seated

Petromat Geotex.

2” lift of ½” Superpave2” lift of SMA

2” lift of ½” Superpave

Contributions from PCC remove and replace

Largest Contributer PercentageTotal Energy BTU PCC Production 51.2%Fossil Fuels BTU PCC Production 39.9%Coal BTU PCC Production 71.0%Natural Gas BTU Steel Production 58.9%Petroleum BTU PCC Truck Transport 29.6%CO2 g PCC Production 75.6%CO g Steel Production 49.4%NOx g PCC Production 74.0%SOx g Steel Production 38.1%CH4 g Coal Production 33.9%PM2.5 g Coal Production 45.8%PM10 g PCC Production 76.0%SO2 g PCC Production 99.8%N2O g Steel Production 28.4%VOC g PCC Production 39.3%

Global Warming Potential g CO2 PCC Production 74.6%Acidification moles H+ /g PCC Production 77.1%HH Criteria Air milli - DALYs/g PCC Production 70.0%Eutrophication g N PCC Production 74.0%Photochemical Smog g NOx PCC Production 72.3%

PCC Remove and Replace

Contributions from HMA remove and replace

Largest Contributer PercentageTotal Energy BTU HMA Production 29.8%Fossil Fuels BTU HMA Production 30.4%Coal BTU Electricity Production 74.4%Natural Gas BTU HMA Production 51.4%Petroleum BTU Bitumen Production 20.1%CO2 g HMA Production 31.6%CO g HMA Production 55.4%NOx g Bitumen Production 48.8%SOx g Electricity Production 39.8%CH4 g Natural Gas Production 67.6%PM2.5 g HMA Production 52.7%PM10 g HMA Production 34.5%SO2 g Bitumen Production 97.4%N2O g Aggregate Production 64.7%VOC g HMA Production 61.2%

Global Warming Potential g CO2 HMA Production 30.2%Acidification moles H+ /g Bitumen Production 61.3%HH Criteria Air milli - DALYs/g Bitumen Production 40.2%Eutrophication g N Bitumen Production 48.8%Photochemical Smog g NOx Bitumen Production 44.5%

HMA Remove and Replace

Contributions from CSOL

Largest Contributer PercentageTotal Energy BTU HMA Production 31.2%Fossil Fuels BTU HMA Production 32.1%Coal BTU Electricity Production 77.3%Natural Gas BTU HMA Production 51.5%Petroleum BTU Bitumen Production 23.5%CO2 g HMA Production 33.6%CO g HMA Production 57.7%NOx g Bitumen Production 51.7%SOx g Electricity Production 42.3%CH4 g Natural Gas Production 69.9%PM2.5 g HMA Production 53.7%PM10 g HMA Production 34.8%SO2 g Bitumen Production 97.4%N2O g Aggregate Production 70.6%VOC g HMA Production 64.4%

Global Warming Potential g CO2 HMA Production 32.1%Acidification moles H+ /g Bitumen Production 63.9%HH Criteria Air milli - DALYs/g Bitumen Production 41.0%Eutrophication g N Bitumen Production 51.7%Photochemical Smog g NOx Bitumen Production 47.2%

CSOL

Makeup of Impact Assessment

Global Warming (CO2-e / kg)

Acidification (H+ moles-e / kg)

HH Criteria (milli-DALYs / kg)

Eutrophication (N-e / kg)

Photochemical Smog (g NOx-e)

CO2 1.0000 0.0000 0.0000 0.0000 0.0000

CO 0.0000 0.0000 0.0000 0.0000 0.0134NOx 0.0000 40.0400 0.0022 0.0443 1.0000SOx 0.0000 50.7900 0.0000 0.0000 0.0000CH4 21.0000 0.0000 0.0000 0.0000 0.0030PM2.5 0.0000 0.0000 0.1391 0.0000 0.0000PM10 0.0000 0.0000 0.0834 0.0000 0.0000

SO2 0.0000 50.7900 0.0139 0.0000 0.0000N2O 310.0000 0.0000 0.0000 0.0000 0.0000VOC 0.0000 0.0000 0.0000 0.0000 0.7806

Inventory Flow

Air

Em

issi

ons

Impact Assessment

0.00E+00

1.00E+02

2.00E+02

3.00E+02

4.00E+02

5.00E+02

6.00E+02

PCC Replace HMA Replace CSOL

kg C

O2

0.00E+00

1.00E+09

2.00E+09

3.00E+09

4.00E+09

5.00E+09

6.00E+09

7.00E+09

PCC Replace HMA Replace CSOL

BTU

Global Warming Potential Energy Use

Impact Assessment

Eutrophication Acidification

0.00E+00

1.00E-02

2.00E-02

3.00E-02

4.00E-02

5.00E-02

6.00E-02

7.00E-02

8.00E-02

PCC Replace HMA Replace CSOL

kg N

0.00E+00

2.00E+01

4.00E+01

6.00E+01

8.00E+01

1.00E+02

1.20E+02

PCC Replace HMA Replace CSOL

mol

es H

+

Impact Assessment

Human Health Criteria Air Photochemical Smog

0.00E+00

2.00E-02

4.00E-02

6.00E-02

8.00E-02

1.00E-01

1.20E-01

1.40E-01

1.60E-01

PCC Replace HMA Replace CSOL

mill

i-DA

LYs

0.00E+00

2.00E+02

4.00E+02

6.00E+02

8.00E+02

1.00E+03

1.20E+03

1.40E+03

1.60E+03

1.80E+03

PCC Replace HMA Replace CSOL

k N

Ox

Total Energy Use0.

09

2.84

0.14

0.48 0.

64

0.13

0.04

3.76

0.61

0.50

1.11

0.21

0.00

2.14

0.25

0.24

0.62

0.21

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

PCC Removal or Crack and Seat

Materials Production

Construction Transportation Fuel and Electricity Production

Rehabilitation

Tota

l Ene

rgy

(TJ)

PCC HMA CSOL

Global Warming Potential3

464

5

35 39

51

216

20

37

79

80

123

8 18

44

8

0

50

100

150

200

250

300

350

400

450

500

PCC Removal or Crack and Seat

Materials Production

Construction Transportation Fuel and Electricity Production

Rehabilitation

Glob

al W

arm

ing

Pote

ntial

(kg

CO

2-e)

PCC HMA CSOL