Virginia Concrete Conference
March 4, 2011
Year 1 Findings
MIT Concrete Sustainability Hub
John M. Prentice
Vice President Industry Liaison – PCA
A Brief History
First Contacts
Opening of
CSHub
Life Cycle Assessment
(LCA)
“The Edge of Concrete”
H. Jennings Joined as
Executive Director
Concrete Science (CSP)
“The Genesis of
Concrete”
Public
Announcement
of Year 1
Findings
Industry Day
Goals and Projects of CSHub
• Sustainable and Holistic Development of
the Cement and Concrete Industry.
Life Cycle Analysis (LCA)
Concrete Sciences (CSP)
Goal: Develop a complete
understanding of CO2e of
concrete in:
Goal: Develop a first principle
understanding of Cement and
cement based systems.
- Pavement
- Buildings
- More with Less
- Higher Performances
SHORT-TERM BENEFITS TO
INDUSTRY
MEDIUM-TERM BENEFITS TO
INDUSTRY
• Develop information useful to policy and code
• Introduce transformational strategies for new
technologies
Introduction to MIT CSHub
Life Cycle
Assessment
Pavement LCA
2 PIs
3 Researchers
Residential
Buildings
Building LCA
2 PIs
7 Researchers
Commercial
Buildings
Concrete
Science
Multiscale Experimentation
Modeling & Simulation
8 PIs
14 Researchers
CSHub@MIT: Industry–
Academia Partnership
Life Cycle
Assessment
Concrete
Science
Industry
Input
Industry
Input
Concrete Sustainability Hub
(PCA, RMC, MIT)
Industry
Advisory Committees
Life Cycle Assessment
PIs: John Ochsendorf, Les Norford, and Timothy
Gutowski
Motivations for LCA work
1) Growing demand for sustainability and quantifying performance
of structures
2) Increasing recognition that green design includes the construction
phase and the operating phase of structures
3) Advantages of concrete
construction in lowering
the emissions in the
operating phase
Significance
•MIT’s LCAs assess all life cycle phases as
comprehensively as possible
Pre-use phase
Use phase
End of life
•Buildings and pavements under study represent designs
built to codes/standards
•Results are shown in terms of energy usage and Global
Warming Potential (lbs CO2e)
Outcomes of the LCA Project
• Quantify advantages over full life cycle
• Identify areas for improvement
• Build foundations for future studies
Software: GaBi 4
• Leading life cycle assessment program
• Data for LCA is:
– Obtained from peer-reviewed sources
– Taken from in-house database
– Input from outside sources
• Convenient impact assessment interface
Life Cycle Assessment of Pavements
Mehdi Akbarian, Alex Loijos, Nicholas Santero
PIs: John Ochsendorf and Tim Gutowski
Problem Statement
Goal:
• We want to make pavements more sustainable
• Find the largest opportunities to reduce emissions in the pavement life cycle?
Scope:
• LCA of High, Moderate, and low volume roadways
• Functional Unit: 1 mile of roadway
• Analysis Period: 50 years
System Boundary
LCA Approach
Where:
GHG Emissions of High Volume Roadways(Kg CO2e)
50
40
Pavement-Vehicle Interaction
30
Albedo, Lane Closures, Lighting,
Carbonation
20
Production
10
0
Flexible
Rigid
Pavement-Vehicle Interaction
Pavement
Deflection
Pavement parameters:


Pavement type and structure
Pavement temperature
Pavement Roughness
Deflection Effect: Asphalt vs.
Concrete
Increase in Fuel Consumption of Vehicles on Asphalt Pavement
CHANGE IN FUEL CONSUMPTION (liters/100km)
10
10.0
National Research Council of Canada (NRC)
Effect of Pavement Type on Vehicle Fuel Consumption - Phase III
8
6
8.0
6.0
The effect of pavement-vehicle interaction on fuel consumption
4
is attributed
to flexible pavements as additional GHG emissions.4.0
2
2.0
0
0.0
-2
NRC I
Zaniews
Zaniews (Trucks
ki
ki (Cars)
100
(Trucks)
km/hr)
Upper
4.7
Insignificant
8.5
1.5
Lower
5.9
-0.7
4.0
average
7.2
0.4
4.3
NRC I
(Trucks
60
km/hr)
1.8
NRC II
(Trucks
100
km/hr)
2.3
1.6
1.7
1.4
1.8
NRC II NRC III ( NRC III NRC III NRC III
Michigan NPC
De
U Texas
(Trucks
Truck
(Full
(Empty
(Cars
SU
(Trucks Graaff
(Cars 60
60
100
Truck 60 Truck 60
100
(Trucks
at 80 (Cars 90
km/hr)
km/hr)
km/hr)
km/hr)
km/hr)
km/hr)
60km/hr) km/hr)
km/hr)
2.2
0.7
0.4
0.5
0.3
0.9
0.2
0.2
0.3
0.1
0.1
-0.1
1.4
0.4
0.2
0.4
0.2
0.4
1.0
0.0
-0.2
1.8
0.6
0.3
0.5
0.3
0.7
1.0
0.1
0.0
-2.0
Roughness Effect
Increase in Fuel Consumption Due to Change in Roughness
14
Sandberg (All cars)
CHANGE IN FUEL CONSUMPTION (%)
12
10
Descornet (All)
8
Du Plessis (Trucks)
Laganier & Lucas (Cars)
6
Du Plessis (Cars)
FHWA (Trucks)
4
2
NCAT (All)
Michigan SU (All)
0
0
1
2
3
4
5
CHANGE IN IRI VALUE (m/km)
6
7
8
Model Scenarios
High volume road:
Moderate volume road:
Low volume road:
 Route 101 in Oxnard, CA  Route 67 in Ramona, CA  Route 178 in Sequoia
(at Route 232 junction)
(at Route 78 junction)
National Forest
 65 mph highway
 35 mph urban road
 35 mph rural road
 3 lanes each direction + 4  2 lanes in each direction +  1 lane in each direction
shoulders
4 shoulders
 Daily traffic: 139,000
 Daily traffic: 23,400
 Daily traffic: 5,200

(Of which trucks: 6,672)
(Of which trucks: 1,357)
(Of which trucks: 468)
Full Life Cycle Emissions for
Different Traffic Volumes
High volume
Moderate volume
Low volume
Pavement LCA – In Summary
• Concrete production emissions are comparable to
asphalt, but concrete use phase emissions are lower
– High traffic volume concrete highways may have up to 80% lower
emissions for the entire life cycle compared to asphalt highways because
of the greater fuel efficiency of vehicles driving on concrete pavements.
• But no two pavements are alike
– The total carbon footprint of a pavement can vary by two orders of
magnitude depending on the traffic volume, rehabilitation schedule, and
many other assumptions.
• Pavement roughness and deflection are still not
completely understood
– No one has accurately quantified their interactive effects, the effect of
each pavement layer, nor the effect of temperature.
– Studies have not accurately quantified the effect on fuel consumption due
to pavement type, structure, roughness, and vehicle weight over the life of
a pavement
Work for Year Two

Refine fuel consumption models to better account for
pavement-vehicle interactions and to instill greater
confidence in fuel savings due to pavement design.

Continue ISO peer review process to have an expert
critical review of our LCA study.

Policy Analysis - Analyze scenarios that quantify the
carbon emissions associated with proposed renewal and
improved upkeep of the national highway system.

Combine with life cycle economic costing to understand the
economic impact of reducing greenhouse gas emissions.
Life Cycle Assessment of Buildings
PIs: John Ochsendorf, Les Norford
Projects
Commercial Buildings
Residential Buildings
Single family
• 2,400 ft2 total floor area
• 2 stories
• Glazing ratio – 15%
• Insulated roof (per code)
•
•
•
•
•
•
Large Commercial Office Building
500,000 ft2
12 Stories + Basement
40% Glazing
60% Aluminum Panel Rain Screen
VAV System
Multi-family
• 10,800 ft2 total floor
area
• 4 stories
• 2700 ft2 Floor plate
• Glazing ratio – 18%
Energy Modeling Scope
ENERGY USE
HVAC
HVAC
Internal Gains
Solar Gains
System Type
System Sizing
Fuel Type
CoP or Efficiency
Temperature Setpoints
Schedule
Lights, People, Equipment
Schedule
Glazing Ratio
Glazing Properties
Envelope Properties and Dimentipns
Air Infiltration
Plug Loads & Lighting
Fuel
Schedule
Hot Water Production
Fuel Type
Efficiency
Schedule
Life Cycle Assessment of
Commercial Buildings
Andrea Love, AIA, LEED A.P.
Libby Hsu, SMBT
Commercial Building Results
Global Warming Potential Over a 75-Year Lifespan
Embodied CO2-equiv
Operating CO2-equiv
End-of-Life CO2-equiv
2000
1800
lbs/ft2 CO2-equivalent
1600
1400
1200
1000
800
600
400
200
0
Concrete Chicago
Steel Chicago
Concrete Phoenix
Steel Phoenix
Year Two Work
1.
LCA Sensitivity Study
• Strategies to reduce CO2e of concrete
• More efficient material usage
2.
Envelope Assemblies
•
•
•
•
3.
Thermal mass
Percent glazing
Albedo
Thermal bridging
Advanced HVAC Strategies
• Passive strategies
• Active strategies
Life Cycle Assessment of
Residential Buildings
Jason Tapia, M.S., AIA, LEED AP
Marzena Kasia Fydrych, M.S., M.Eng.
Lori E. Ferriss, M.Eng.
Michael Street, B.S. Candidate
Wall Systems
Insulated Concrete Forms (ICF)
Wood Frame
•Industry requested a comparison of ICF versus wood frame construction
29
RESULTS: Single Family GWP Life Cycle
Global Warming Potential Over a 75-Year Lifespan
Embodied CO2-equiv
Operating CO2-equiv
End-of-Life CO2-equiv
2.50E+03
lbs/ft2 CO2-equivalent
2.00E+03
1.50E+03
1.00E+03
5.00E+02
0.00E+00
Concrete Chicago
Wood Chicago
Concrete Phoenix
Wood Phoenix
RESULTS: Multi-Family GWP Life Cycle
Global Warming Potential Over a 75-Year Lifespan
Embodied CO2-equiv
Operating CO2-equiv
End-of-Life CO2-equiv
2000
1800
lbs/ft2 CO2-equivalent
1600
1400
1200
1000
800
600
400
200
0
Concrete Chicago
Wood Chicago
Concrete Phoenix
Wood Phoenix
Work for Year Two
Passive Strategies
• Developing techniques for improving the operation of
concrete homes based on regional specificity
More research is needed to improve air tightness data for low
rise construction
Prototype Homes
• Designing next generation concrete homes
LCA: Year One Accomplishments
• Three teams
• Architecture
• Building Technology Program
• Civil Engineering
• Mechanical Engineering
• Technology and Policy Program
• Material Science
• Comprehensive LCA models
• Pavements
• Building
• Foundation for further studies
• Identifying competitive advantages and areas of
improvement
For more information:
• web.mit.edu/cshub
• cshub@mit.edu