Caltrans Pavement Life Cycle Assessment (LCA) and its Use
to understand Environmental Impacts
Deepak Maskey
Senior Transportation Engineer
Pavement Program, Caltrans
CALAPA Spring Asphalt Pavement Conference & Equipment Expo
March 23-24, 2023

Pavement Sustainability
• Long-life pavements
• Fuel efficient pavements
• Pavement preservation
• Recycled materials
• Environmental project declaration (EPD)
• Environmental Life Cycle Assessment (LCA)
• Social Life Cycle Assessment (SLCA)
• Life Cycle Cost Analysis (LCCA)
• Multicriteria Decision Making (LCA+LCCA)

Similar Name, Similar Approach Different Sustainability
Pillar
• Life Cycle Assessment (LCA)
o Environmental (sometimes referred to as LCA or eLCA)
o Social (sometimes referred to as SLCA)
• Life Cycle Cost Analysis (LCCA)
• Similar:
o Consider full life cycle, complete system
o Use same life cycle of pavement activities
• Different:
o LCCA is for cost impacts
o LCA is for environmental impacts, energy use and finite resource depletion
o SLCA is for social impacts

Why LCA?
•Produces quantification of environmental, energy
and finite resource use impacts
•Considers
oFull life cycle of production, consumption/use/
maintenance/rehabilitation and end of life of products
and services
oSystem boundaries that are sufficiently defined to
capture important interactions and potential unintended
consequences

How do we work towards sustainability?
• Is it just reducing greenhouse gases (GHG) and making sure we are
recycling?
oThese relate back to environmental impacts, economics and social well
being, but there is a lot more
oGHGs and recycling do not address all the environmental impacts
• Need to set sustainability goals and routinely use quantitative
approaches in our work to address and work towards those goals

Good answers will come from full system and complete life
cycle-based decision making
• Full System for pavement considers:
oResources
oProcesses
oStructure/traffic/climate/soil application
oAll environmental and resource use impacts of interest
oInteractions and effects on other systems
• Complete Life Cycle for pavement:
oLooks at consequences of current decisions as far into the future as can be
calculated with some certainty
oLooks at effects of current decisions on ability to make future decisions

Pavement LCA Framework (Adapted from A.A.Butt 2014)
• Recycle
• Dispose
• Incinerate
• Transport
• Albedo
• Lighting
• Pavement-
Vehicle
Interaction
• Mill
• Lay
• Compact
• Transport
• Laying
• Compaction
• Transport
• Extraction
• Processing
• Transportation
Material Construction Maintenance Use End Of Life
Electricity Raw Materials
Recycled
Materials
Pavement Design and life
time prediction
Input
Output
Airborne Emissions Waste Recyclable Materials Energy
Waterborne Emissions

eLCAP

Overview of eLCAP
• eLCAP is a web-based transport infrastructure LCA tool
• Capable to model the life cycle of any pavement project
• eLCAP database library is developed based on the California specific extensive
inventories of
omaterials and mixes,
oconstruction equipment and activities,
otransportation modes,
ouse stage impacts (based on IRI and vehicle fuel use),
oend of life scenarios
• eLCAP computes 18 different impact categories for any user defined case

Overview of eLCAP
• eLCAP data and models have been reviewed by three external reviewers who:
• are road transport infrastructure experts, and
• have extensive knowledge of LCA
• Current version of eLCAP uses proprietary data, therefore per licensing
agreement can only be used by:
• Caltrans
• UC Davis
• Working to develop models in OpenLCA and use in eLCAP to replace models
developed in a software that uses proprietary data
• Plan to make eLCAP available for others by early 2024*

Basic Unit Process Used in LCA
• Example processes:
• Produce one ton of asphalt concrete
• Produce one cubic yard of concrete
• Haul 25 tons of aggregate base
• Place a slurry seal

An LCA model of FDR-Cement with asphalt overlay, cradle-
to-laid

eLCAP Database: Material Stage using 2012 California
electricity mix

Asphalt Binder Material Stage Impacts

Data Quality
Assessment

Default
&
User Defined
Processes:
Materials,
Construction
Equipment,
& Transport

Reclaimed
Asphalt
Pavement
and Recycled
Concrete
Aggregate

Compare Alternatives
Alternative Layer Other Ops Year Built Service life
1: Rehab. &
Preserv.
HMA Overlay Mill & Fill 2 in. 0 22
Slurry 15 7
HMA Overlay Mill & Fill 2 in. 22 22
Slurry 37 7
2: Rehab.
Only
HMA Overlay Mill & Fill 2 in. 0 18
HMA Overlay Mill & Fill 2 in. 18 18
HMA Overlay Mill & Fill 2 in. 36 18

Rehab. 1
Rehab. 2
Rehab. 1
Preservation 1
Rehab. 2 Rehab. 3
Preservation 1
CASE 2: REHABILITATION ONLY
CASE 1: REHABILITATION AND PRESERVATION

75,364
9,726 2,094
88,522
11,404
2,468
MATERIALS TRANSPORT CONSTRUCTION
Rehab & Preservation GWP (kg CO2-eq)
Rehab. Only GWP (kg CO2-eq)

Use Stage with Low Traffic: BUT-70-E
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
9,000
10,000
2023 2023 2024 2024 2025 2025 2026 2026 2027 2027 2028
Cumulative
GHG
(CO2-Eq
tonne)
Year
Cumulative Life Cycle (All Events) GWP
Use Stage: IRI + Fuel Use on Ideal Road Use Stage: IRI Only Use Stage: Fuel Use on Ideal Road Only

Summary
• Life cycle assessment (LCA) can be used to quantify environmental impacts
• Guidance for applying LCA to pavements is available
• Tools for applying LCA to pavement sustainability problems are becoming
available
• eLCAP is one of such tools (working to make it available for others to use)
• Primary data from industry can make LCAs meaningful and impactful

Thanks to
many
colleagues!
Questions?
• Contacts:
• Deepak Maskey - deepak.maskey@dot.ca.gov
• Ali A. Butt - aabutt@ucdavis.edu
• John T. Harvey - jtharvey@ucdavis.edu