applications of lca for network-level pavement...
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Center for
Sustainable
Transportation
Infrastructure
Applications of LCA for Network-Level
Pavement Management
Gerardo W. Flintsch
Director, Center for Sustainable Transportation Infrastructure
Professor of Civil and Environmental Engineering
Center for
Sustainable
Transportation
Infrastructure Acknowledgements
University of Coimbra & Portuguese Foundation for Science and Technology (Grant SFRH/BD/79982/2011)
MODAT – Multi-Objective Decision-Aid Tool for Highway Asset Management
EMSURE – Energy and Mobility for Sustainable Regions
– Joao Santos
– Adelino Ferreira
National Sustainable Pavement Consortium
Mississippi, Pennsylvania, Wisconsin, and Virginia
DOT, FHWA, and Virginia Tech
– James Bryce
Center for
Sustainable
Transportation
Infrastructure Contents
Background
Framework
Example Applications
Conclusions
Center for Sustainable
Transportation Infrastructure
Center for
Sustainable
Transportation
Infrastructure
Background
Center for Sustainable
Transportation
Infrastructure
Center for
Sustainable
Transportation
Infrastructure
DATABASEIN
VE
NT
OR
Y
CONDITION
USAGE
MAINTENANCESTRATEGIES
INFORMATION MANAGEMENT
NETWORK-LEVEL ANALYSIS
TOOLS
PROJECT LEVEL
ANALYSIS (Design)
WORK PROGRAM
EXECUTION
PERFORMANCE
MONITORING
FEEDBACK
CONDITION ASSESSMENT
PRODUCTS
NETWORK-LEVEL
REPORTSPerformance AssessmentNetwork NeedsFacility Life-cycle Cost Optimized M&R ProgramPerformance-based Budget
CONSTRUCTION
DOCUMENTS
GRAPHICAL
DISPLAYS
NEEDSANALYSIS
PRIORITIZATION / OPTIMIZATION
PERFORMANCE PREDICTION
PROGRAMMINGPROJECT SELECTION
Goals & PoliciesSystem PerformanceEconomic / Social &
Environmental
Budget Allocations
STRATEGIC ANALYSISThe Asset Management
ProcessEconomic, Social
and Environmental
Impacts
Center for
Sustainable
Transportation
Infrastructure National Sustainable Pavement Consortium
Objective: To establish a research consortium focused on enhancing pavement sustainability
Identification and evaluation of novel products, practices, and pavement systems
Best practices for sustainable pavement management
Climatic changes adaptation
Scope:
Research
Applied – Shorter term quick gains
Basic – Answer fundamental questions
Education
Materials to support short courses
Materials to help develop academic classes
Outreach
Short courses, seminars, webinars and workshops
Center for
Sustainable
Transportation
Infrastructure
National Sustainable Pavement Consortium
LCA for Pavements Projects
Literature Review - LCA
Energy Sources
Probabilistic Analysis
Multi-criteria Analysis
Collaboration with
University of Coimbra
Project Level Analysis
Network Level Analysis
Expand Boundaries Given Updated
Models
Use LCC-LCA Results in Decision Making
Include LCA in Network Level
Analysis
Center for
Sustainable
Transportation
Infrastructure Objective
To develop a comprehensive approach and supporting tools to
calculate the life cycle impacts of pavement maintenance and
rehabilitation projects and management approaches
–Considers comprehensive and integrated pavement life cycle cost
and (environmental) life cycle assessment models
–Covers the whole pavement’s life cycle (cradle to grave)
–Balances performance, cost and environmental impacts
To apply the model to improve the management of pavement
assetsCenter for Sustainable
Transportation Infrastructure
Center for
Sustainable
Transportation
InfrastructureAntecedent: Adding a 3rd Objective: Minimizing the Life
Cycle Environmental Impact
Objectives:
– Assess the environmental impacts of road-related practices,
strategies, and materials
– Implement a procedure to include these eco-efficiency values
into a more comprehensive decision support system
Evaluation of
alternatives/
strategies
Optimal
StrategyPerformance
Environment
CostsMulti-
Attribute
optimization
Giustozzi, Crispino, & Flintsch, “Multi-Attribute Life Cycle Assessment of Preventive Maintenance Treatments on Road
Pavements for Achieving Environmental Sustainability,” The International Journal of Life Cycle Assessment, 2012.
Center for
Sustainable
Transportation
Infrastructure
Framework
Center for Sustainable
Transportation
Infrastructure
Center for
Sustainable
Transportation
InfrastructureLCCA
Optimization of Transportation Costs
Center for
Sustainable
Transportation
Infrastructure Life Cycle Assessment
0
20
40
60
80
100Climate Chage (CC)
Acidification (AC)
Eutrofization (EU)
Polution that affectHuman Health (HH)
Photochemical Smog(PS)
Consumption of MineralResourses (ADR MR)
Consumption ofEnergetic Resourses
(ADR ER)
What factors
are important?
How Important?
How we
account for
them?
Santos, J., Ferreira, A. and Flintsch, G.W., “A life cycle assessment model for pavement management: methodology
and computational framework,” International Journal of Pavement Engineering, 2014, pp. 1-20
Center for
Sustainable
Transportation
Infrastructure Life Cycle Sustainability Assessment (LCSA)
Source: UNEP (2012) Social Life Cycle Assessment and Life Cycle Sustainability Assessment
The evaluation of all environmental, social and economic
negative impacts and benefits in decision-making
processes towards more sustainable products throughout
their life cycle.
http://www.lifecycleinitiative.org/starting-life-cycle-thinking/life-cycle-approaches/life-cycle-sustainability-assessment/
Center for
Sustainable
Transportation
InfrastructurePavement Phases Considered in the LCCA/LCA
Following
– International Standard Organization (ISO, 2006) & UCPRC Pavement LCA (Harvey et al., 2010)
Construction
and M&R
Usage
Materials
Extraction
and
Production
End-of-Life
WZ
Congestion
Transportation
Center for
Sustainable
Transportation
Infrastructure
DEC-UC
Inp
ut
Dec
isio
n
Su
pp
ort
MO
O
Mod
ule
LC
C-
LC
A
Mod
el
Multi-
Obje
ctive O
ptim
ization
-Base
d
Decis
ion S
upp
ort
Syste
m f
or
Su
sta
ina
ble
Pa
ve
me
nt
Ma
na
ge
me
nt
MOO Module
Decision Variables
Model Formulation
Objective Functions
Constraints
Solution Approach
Solution Algorithm
Augmented Weighted
TchebycheffAHGA
MaterialsWZ Traff.
Manag.Construction
and M&RUsage EOL
T
T
T
TDisposal
T
System Boundaries
T
Integrated Pavement LCC-LCA Model
Energy Sources Production
Decision-Support Module
Best Optimal Compromise
Solution (BOCS) Selection
Pareto Front
BOCS's Performance Evaluation:- Optimal M&R strategy- Pavement's functional quality report- LCHAC report- LCRUC report- LCI report- LCEI report
Data Management Module
Getting Started
Results Report Module
General Inputs Detailed InputsGoal and scope
definition
Center for
Sustainable
Transportation
InfrastructureMulti-Objective Optimization Model
Formulation
Objective Functions
Agency Cost
User Costs
Env. Impacts
Constraints
…
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Mod
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MOO Module
Decision Variables
Model Formulation
Objective Functions
Constraints
Solution Approach
Solution Algorithm
Augmented Weighted
TchebycheffAHGA
MaterialsWZ Traff.
Manag.Construction
and M&RUsage EOL
T
T
T
TDisposal
T
System Boundaries
T
Integrated Pavement LCC-LCA Model
Energy Sources Production
Decision-Support Module
Best Optimal Compromise
Solution (BOCS) Selection
Pareto Front
BOCS's Performance Evaluation:- Optimal M&R strategy- Pavement's functional quality report- LCHAC report- LCRUC report- LCI report- LCEI report
Data Management Module
Getting Started
Results Report Module
General Inputs Detailed InputsGoal and scope
definition
Center for
Sustainable
Transportation
Infrastructure Multi-Objective Optimization Model Solution Approach
Define a combined
Objective Function
with additional constraints
Solve using and Adaptive
Hybrid Genetic Algorithm
,w,N,...,i,w
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iobji 110
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Subjected to:
Center for
Sustainable
Transportation
Infrastructure
LC
C-L
CA
Mo
del
MOO Module
Decision Variables
Model Formulation
Objective Functions
Constraints
Solution Approach
Solution Algorithm
Augmented Weighted
TchebycheffAHGA
MaterialsWZ Traff.
Manag.Construction
and M&RUsage EOL
T
T
T
TDisposal
T
System Boundaries
T
Integrated Pavement LCC-LCA Model
Energy Sources Production
Decision-Support Module
Best Optimal Compromise
Solution (BOCS) Selection
Pareto Front
BOCS's Performance Evaluation:- Optimal M&R strategy- Pavement's functional quality report- LCHAC report- LCRUC report- LCI report- LCEI report
Data Management Module
Getting Started
Results Report Module
General Inputs Detailed InputsGoal and scope
definition
LCC-LCA Model
Economic Life Cycle Inventory Environmental Life Cycle Inventory
Life Cycle Costs Assessment Life Cycle Impacts Assessment
Analysis Definition: Goal and Scope General InputsDetail Inputs
Materials Extraction and
Production
Construction and M&R
WZ Traffic Management
UsageEnd-of-
LifeT
T T
T
T
T
Energy Sources Production
Customizable Database
Disposal Facility
Objective Functions Constraints
Multi-Objective Optimization-Based Life Cycle Costing – Life Cycle Assessment Integrated Model
o Internal Costs:- Highway Agency Costs;- User Costs;
o External Costs:- Environmental Costs;- Social Costs:
o Airborne Emissionso Materials Consumptiono Energy Sources Consumption
o Conventional Life Cycle Costingo Environmental Life Cycle Costingo Societal Life Cycle Costing
o Impact Categorieso Category Indicatorso Categorization Factors
- Optimal Pavement Maintenance and Rehabilitation Plan- Life Cycle Costs Assessment Results
- Life Cycle Impacts Assessment Results
Energy Sources
Life Cycle
Inventories
LCCA LCA
Santos, J., Flintsch, G. and Ferreira, A. “Environmental and economic assessment of pavement construction and management
practices for enhancing pavement sustainability,” Resources, Conservation & Recycling, 2017, 116, pp. 15-31.
Center for
Sustainable
Transportation
Infrastructure
Dec
isio
n
Su
pp
ort
MOO Module
Decision Variables
Model Formulation
Objective Functions
Constraints
Solution Approach
Solution Algorithm
Augmented Weighted
TchebycheffAHGA
MaterialsWZ Traff.
Manag.Construction
and M&RUsage EOL
T
T
T
TDisposal
T
System Boundaries
T
Integrated Pavement LCC-LCA Model
Energy Sources Production
Decision-Support Module
Best Optimal Compromise
Solution (BOCS) Selection
Pareto Front
BOCS's Performance Evaluation:- Optimal M&R strategy- Pavement's functional quality report- LCHAC report- LCRUC report- LCI report- LCEI report
Data Management Module
Getting Started
Results Report Module
General Inputs Detailed InputsGoal and scope
definition
Decision Support Model
Choose the solution in the Pareto front furthest from the
most inferior solution, according to the membership function concept in
the fuzzy set theory
The solution with the maximum value of b j is considered as the best
optimal compromise solution (BOCS)
b j = the fuzzy cardinal priority ranking of each non-dominated solution
mini
maxi
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1b
Center for
Sustainable
Transportation
Infrastructure
Example Applications
Center for Sustainable
Transportation
Infrastructure
Center for
Sustainable
Transportation
Infrastructure
Example I – LCCA/LCA Model only
Life-Cycle Assessment of I-81 Recycling
Project in Virginia, USA
Functional unit: Section of
Interstate 81:
–5.89 km long
–2 lanes
–Directional AADT in 2011:
25000 (28% trucks)
–Annual traffic growth rate: 3%
–Project analysis period: 50
years
50 year time horizon
All phases except EOL
– Use phase evaluated using Chatti
and Zaabar’s NCHRP models and
MOVES
– Traffic congestion effects
considered using MOVES
– Impact Assessment using TRACI
Each alternative had different
rehab. schedules
Center for
Sustainable
Transportation
Infrastructure Compared 3 Strategies
• Initial Intervention: In-Place recycling;
• M&R plan: VDOT’s maintenance actions performed in years 12, 22, 32 and 44
Recycling-based
• Initial Intervention: Traditional reconstruction
• M&R plan: VDOT’s maintenance actions performed in years 12, 22, 32 and 44
Traditional Reconstruction
• Initial Intervention: Corrective Maintenance
• M&R plan: VDOT’s maintenance actions performed in years 4, 10, 14, 18, 24, 28, 34, 38, 44 and 48
Corrective Maintenance
Center for
Sustainable
Transportation
InfrastructureExample of LCA Results
Impact on Climate Change
2 1
00
15
2
20
6
3 5
93
112 9
26
3 7
88
26
0
72
1
3 9
42
112 9
26
3 3
47
21
6 46
9
7 3
35
156 8
59
1
10
100
1 000
10 000
100 000
1 000 000
Materials Construction andM&R
Transportation WZ TrafficMangement
Usage EOL
Ton
ne
so
fC
O2
-e
q
Recycling-based Traditional Reconstruction Corrective Maintenance
Santos, J., Bryce, J., Flintsch, G., Ferreira, A. and Diefenderfer, B. (2014). A life cycle assessment of in-
place recycling and conventional pavement construction and maintenance practices. Structure and
Infrastructure Engineering: Maintenance, Management, Life-Cycle Design and Performance, 1-19.
Center for
Sustainable
Transportation
Infrastructure LCCA Comparison
$2
.43
86
$0
.35
82
$0
.23
32
$9
.12
15
$2
.46
51
$(0
.15
19)
$1
4.4
648
$4
.53
87
$0
.72
61
$0
.68
56
$1
0.1
087
$2
.46
51
$(0
.15
19)
$1
8.3
723
$4
.73
78
$0
.52
21
$0
.47
20
$1
8.4
943
$3
.52
70
$(0
.13
59)
$2
7.6
173
-5
0
5
10
15
20
25
30
Materials
Extraction and
Production
Construction
and M&R
Transportation
of Materials
WZ Traffic
Management
Usage EOL Total
NP
V [
M$]
Pavement life cycle phase
Recycling-based Traditional Reconstruction Corrective Maintenance
Santos, J., Bryce, J., Flintsch, G. and Ferreira, A. (2015). A comprehensive life cycle costs analysis of
in-place recycling and conventional pavement construction and maintenance practices. International
Journal of Pavement Engineering (online)
Center for
Sustainable
Transportation
Infrastructure
1.21.41.61.822.22.42.62.83
x 107
60
70
80
90
100
0
10
20
30
40
50
60
70
80
90
Condition
Energy Consumption (MJ)
Co
st
(Ten
s o
f T
ho
usan
ds o
f D
ollars
)
50th Percentile
5th Percentile
95th Percentile
Example II - Incorporating the use-phase into LCA for
pavements
Project-level LCA tool
Compared energy consumption at network level for use
(mainly roughness) and maintenance phases
Probabilistic Network-level LCA
Multi-criteria Analysis
→ Incorporating
Stakeholder’s input
Bryce, J., Katicha, S., Flintsch, G.W., Sivaneswaran, N., Santos, J. “Probabilistic Lifecycle Assessment
as a Network-Level Evaluation Tool for the Use and Maintenance Phases of Pavements.” Journal of the
Transportation Research Board, 2014, vol. 2455 (1), pp. 44-53
Center for
Sustainable
Transportation
Infrastructure Methodology
Defined a marginal energy consumption
–RR energy
–EM energy consumption due to maintenance action
• Materials and Construction, Impact of roughness on vehicles
Evaluate tradeoff between cost, condition and energy consumption
–Each variable has uncertainty
–Used a simple synthetic network
–Monte Carlo Simulation
–Assumed that preventive maintenance impact condition but not
pavement roughness
Center for
Sustainable
Transportation
Infrastructure Results
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
x 106
0
1000
2000
3000
4000
5000
6000
7000
8000
Energy Consumption
Fre
qu
en
cy
Histogram of Energy Consumption
PM
CM
RM
RC
1 2 3 4 5 6 7 8
x 106
0
1000
2000
3000
4000
5000
6000
7000
8000
Energy Consumption (MJ)
Fre
quency
Road 7
Road 3Road 4
Road 1
Road 8
Road 6
Road 5Road 2
1.21.41.61.822.22.42.62.83
x 107
60
70
80
90
100
0
10
20
30
40
50
60
70
80
90
Condition
Energy Consumption (MJ)
Co
st
(Ten
s o
f T
ho
usan
ds o
f D
ollars
)
50th Percentile
5th Percentile
95th Percentile
Center for
Sustainable
Transportation
Infrastructure Discussion & Example of Findings
Multi-criteria approach to
pavement management
–Tradeoff between
maintenance and RR
–Probabilistic approach
facilitates the consideration of
uncertainties and confidence
for decision making
– Increasing maintenance costs up to a point decreases total
energy consumption
Condition (0 to 100 Scale, 100 is Perfect Condition)
Co
st
(Te
ns o
f T
ho
usan
ds o
f D
olla
rs)
70 75 80 85 90
5
10
15
20
25
30
35
40
45
4.6
4.8
5
5.2
5.4
5.6
5.8
6
6.2
6.4x 10
9
Center for
Sustainable
Transportation
Infrastructure
Example III – Environmental and Economic Assessment
of Pavement Construction and Management Practices for
Enhancing Pavement Sustainability
Functional unit:
– 1 km-long 2-lanes
asphalt section
– AADT: 20000
– Traffic Growth Rate: 3%
– PAP: 50 years
Type of scenario ID Scenario name
Conventional
VDOT
1 HMA - 0% RAP
2 HMA - 15% RAP
3 HMA - 30% RAP
4 Sasobit® WMA - 0% RAP
5 Sasobit® WMA - 15% RAP
6 Sasobit® WMA - 30% RAP
Recycling-based
VDOT
7 HMA - 0% RAP
8 HMA - 15% RAP
9 HMA - 30% RAP
10 Sasobit® WMA - 0% RAP
11 Sasobit® WMA - 15% RAP
12 Sasobit® WMA - 30% RAP
Preventive
maintenance
13 Microsurfacing - 0% RAP
14 THMACO - 0% RAP
Santos, J., Flintsch, G. and Ferreira, A. “Environmental
and economic assessment of pavement construction
and management practices for enhancing pavement
sustainability,” Resources, Conservation & Recycling,
2017, 116, pp. 15-31.
Center for
Sustainable
Transportation
Infrastructure Formulation
Maintenance and rehabilitation plans
Pavement Performance Prediction Models:
– CM, RM and RC:
1. Conventional VDOT scenario
CM: 12 and 44
RM: 22
Conventional RC: 32
2. Recycling-based VDOT scenario
CM: 12 and 44
RM: 22
Recycling-based RC: 32
3. Preventive maintenance: Microsurfacing
Conventional RC: 32
Microsurf.:7, 15, 23, 39 and 47
4. Preventive maintenance: THMACO
Conventional RC: 32
THMACO: 7, 16, 24, 39, 47
Center for
Sustainable
Transportation
Infrastructure Solution
Multi-criteria decision making
approach:
–TOPSIS method;
–Combinatorial weight
assignment method for the 3
main criteria: AC; RUC;
Environmental Impacts
–Seven environmental sub-
criteria weighted according to
BEES software’s weights.
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0
Scenario 14
Scenario 9
WHAC WRUC
WEnv
WHAC + WRUC + WEnv = 1 WHAC = 1
WEnv = 1 WRUC = 1
Center for
Sustainable
Transportation
Infrastructure Some Findings
Allowed to compare different pavement management strategies
that can then be applied at the network level
For the conditions considered in this case study
–THMACO-based preventive maintenance strategy has proven to
be the most environmentally-friendly solution.
• It may be linked to current application criteria
–Recycling-based VDOT M&R strategy (HMA containing 30% of
RAP) provides a generally “optimal” balance in a MCDM.
Advancing Transportation
Through Innovation
Santos, J., Flintsch, G. and Ferreira, A. “Environmental and economic assessment of pavement
construction and management practices for enhancing pavement sustainability,” Resources,
Conservation & Recycling, 2017, 116, pp. 15-31.
Center for
Sustainable
Transportation
Infrastructure
Conclusions
Center for
Sustainable
Transportation
Infrastructure Final Remarks
Customizable optimization-based pavement management DSS:
– Integrated pavement LCC-LCA model
–An AHGA mechanism for optimizing the pavement life cycle
–MOO-based pavement life cycle optimization model
Application in real and simulated case studies
–Demonstrated that is applicable and practical
–Provided insights on the efficiency of pavement engineering and
management solutions in improving and balancing environmental
and economic impacts of pavement managementCenter for Sustainable
Transportation Infrastructure
Center for
Sustainable
Transportation
Infrastructure
Applications of LCA for Network-Level
Pavement Management
Gerardo W. Flintsch
Director, Center for Sustainable Transportation Infrastructure
Professor of Civil and Environmental Engineering