Transcript Slide 1

Methods, Impacts and
Opportunities in the Concrete
Building Life Cycle
Lionel Lemay, NRMCA
Life Cycle Assessment
The Process
TRACI – Tool for the Reduction and
Assessment of Chemical and other
environmental Impacts
Quantifying/Prioritizing Impacts
LEED v4
Mfg
Impact
Sust. Sites
Location/Tran
sportation
PCR / EPD
Material LC
Disclosure
Community
Planning
Operational Impact
Innovation
Innovation
Regional
Impacts
Water
Consumption
Energy
Water
Consumption
Energy
Consumption
Heat Island
Stormwater
Site
Remediation
Renewable
Recycled
Content
Locally
Available
Waste
LEED v4 Credit Evolution
SS Credit: Rainwater Management
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Reduce runoff volume
Improve water quality
Replicate natural
hydrology
1-3 points
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Pervious pavement!
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SS Credit: Heat Island Reduction
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Roof and paving areas (2
Points)
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Parking under cover (1 point)
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Pavements with high solar
reflectance (SR)
75% spaces under cover
Roof with high SR, green roof,
solar panels, etc.
Concrete pavement!
EA Credit: Optimize Energy Performance
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Whole Building Energy
Simulation
Building Envelope, HVAC,
Water Heating, Electric
Power, Electric Motors,
Lighting, etc.
1-18 Points for 5% to 50%
Reduction over base
building
MR: Building Life Cycle Impact Reduction
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Option 1. Historic Building Reuse (5 points)
Option 2. Renovation of Abandoned Building (5 points)
Option 3. Building and Material Reuse (1–4 points)
Option 4: Whole Building LCA (3 points)
10% impact reduction (for 3 impacts)
from reference building:
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Global warming potential (Required)
Ozone depletion (CFC)
Acidification
Eutrophication
Tropospheric Ozone
Non-renewable energy
MR: Building Product Disclosure And Optimization
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Environmental Product Declarations (2 Points)
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Life Cycle Assessment
Sourcing Of Raw Materials (2 Points)
Material Ingredients (2 Points)
International Green
Construction Code
Chapter 5: Materials & Resources
503.3 Building
material life cycle
assessment. The
execution of a building
material life cycle
assessment shall be
performed…
Environmental Product Declarations
GREEN BUILDING
Architecture 2030
Who’s Signed On?
2030 Challenge for Buildings
2030 Challenge for Products
Environmental Product Declarations
Environmental Product Declarations
Required by:
• LEED v4
• IgCC
• Architecture 2030
Environmental
Product
Declarations
Life
Cycle
Assessment
Data:
Life Cycle
Inventory Data,
plant specific
Product
Category
Rule
Whole Building LCA
Product LCAs
Whole Building LCA
Pre-use Phase
Cradle to Cradle
Perspective
Use Phase
Global
Warming
Potential
92% to 94.5%
5.5% to 8%
Source: Architecture 2030
MIT Concrete Sustainability Hub
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$10 million investment over next 5 years
Funded equally by RMCREF & PCA
NRMCA providing technical support and
guidance
NRMCA and state associations to play a
critical role in the technology transfer
3 Research Platforms
Concrete Science Platform: Mission
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Scientific breakthroughs toward reducing
CO2 footprint of cement and concrete
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Strength with less material
Lower energy processing
Chemical stability
Building Technology Platform
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Mission: Life Cycle Assessment (LCA) of
Concrete Buildings and Pavements to Identify
Impacts and Opportunities
Research Topics:
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Material Flow Analysis
LCA of buildings
LCA of homes
LCA of pavements
LCCA
Commercial Buildings
Greenhouse Gas Emissions
Industry: 29%
Transportation: 31%
Residential
Buildings: 21%
Commercial
Buildings: 19%
Goal and Scope
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Investigate the role of thermal mass in
reducing carbon emissions
Quantify energy advantages of concrete due
to thermal mass
Identify potential areas for improvement in life
cycle emissions
LCA Model
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GaBi software to conduct the LCA
EnergyPlus for energy simulations
Boundaries
Commercial Building
12 stories
498,590 ft2
Phoenix
Concrete
Steel
Chicago
Benchmark Analysis
2
CO
equivalent
Resources
Water
Global Warming
Potential
Ozone Depletion
Acidification
Eutrophication
Smog Formation
Human Toxicity
Eco Toxicity
Waste
Land Use
Life Cycle Emissions (60 years)
Impacts
Global Warming Potential
Embodied
Energy, 5%
Operating
Energy, 95%
Impact Reductions: Passive Solar
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High thermal capacity
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Energy savings of 5-15%
Benefits of Thermal Mass
THERMAL LAG
Off peak demand
Lower energy costs
DAMPING
Lower peak energy
Smaller HVAC
REDUCED TEMPERATURE SWINGS
Less heating and cooling energy
Materials Used for Thermal Mass
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Water
Adobe brick or
mudbrick
Earth, mud, and sod
Rammed earth
Natural rocks and
stones
Concrete, clay bricks
and other forms of
masonry
Direct Gain System
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South facing glass
admits solar energy
Strikes thermal mass
floors and walls
Absorbs heat during day
Radiates heat at night
Utilizes 60 - 75% of
sun's energy
Indirect Gain System
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Mass between sun and
living space
Wall absorbs sunlight
Transfers heat by
conduction
Operable vents permit
convection into living space
When vents are closed heat
radiates into living space
Utilizes 30 - 45% of the
sun's energy
Isolated Gain System
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Separate from living area
Sunroom is best example
Heat retained in mass wall
and air of sunroom
Vents heat living space by
convection during day
Wall heats living space by
radiation at night
Utilize 15 - 30% of the
sunlight striking the glass
Impact Reductions: Low-lift Cooling
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Pre-cool concrete with embedded chilled
water pipes
Use efficient low-lift chillers
Saves 37-84% of cooling energy
Impact Reductions: Lighting Controls
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Strategies studied:
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Façade systems
Shading systems
Building massing
Daylighting yielded
greatest reductions
71% in perimeter
zone lighting by using
sensors and dimmers
Impact Reductions: Structural System
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Recommendations made to reduce GWP
GWP could change slightly if different
structural systems were implemented
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Change GWP by a small percentage
GWP would still be similar to steel frame
Impact Reductions: Mix Design
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More efficient mix designs
Increased use of SCMs
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Fly ash
Slag cement
Silica Fume
Increasing fly ash from 10% to 25%
Decrease pre-use embodied GWP 4.3%
0.18-0.25% reduction of total GWP for 60year life span
Residential Buildings
Greenhouse Gas Emissions
Industry: 29%
Transportation: 31%
Residential
Buildings: 21%
Commercial
Buildings: 19%
Structural Systems Considered
Insulated Concrete Forms (ICF)
Traditional Wood Framing
Benchmark Single Family Building
2 stories
2,400 ft2
ICF
Wood
Phoenix
Chicago
Benchmark Multi-Family Building
4 stories
33,763 ft2
Phoenix
ICF
Wood
Chicago
Structures
2 stories
Single Family
4 stories
Multi-Family
Impact Reduction - Air Tightness
Impacts
Further Reduction: Passive Solar Design
Pavements
Greenhouse Gas Emissions
Industry: 29%
Transportation: 31%
Residential
Buildings: 21%
Commercial
Buildings: 19%
LCA of Concrete Pavements
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2.6 million miles of public roadways
3 trillion vehicle miles
Road transport contribute most GHG of
any transport mode
Construction and maintenance consumes
energy and resources
Goal and Scope
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Assess environmental
impact of concrete
pavements
For entire life cycle
Quantify cumulative
environmental impacts
Ways to reduce GHG
emissions
Supporting Designers and Decision-Makers
Tools
•Performance:
Design
Method
•Cost: LCCA
•Environmental
Impact: LCA
Research improves
existing tools by:
•Quantifying novel
issues
•Characterizing risk
•Highlighting data that
are key impact drivers
Goal
Pavement
design that
balances:
•Performance
•Cost
•Environmenta
l Impact
This enables designers and decision-makers to:
•Focus on key drivers of decisions
•Make fully informed decisions
•Understand risk and uncertainty in decisions
LCA for Pavement Environmental Impact
Incorporating use phase in pavement
LCA is a recent innovation
• Pavement-Vehicle
Interaction
 Roughness
 Deflection
• Albedo
• Carbonation
• Lighting
• Extraction and
production
• Transportation
• Onsite equipment
Materials
Construction
Use
• Pavement
Removal /
Milling
• Landfilling
• Recycling
• Transportation
End-of-Life
Maintenance
• Materials
• Construction
• Traffic delay
Reducing Carbon Footprint
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Modify Cement Production Process
Increase Use of Supplementary Cementitious
Materials
Increase Albedo of Pavement Surface
Decrease Deflection and Roughness
Optimally Time Rehabilitation Cycles
Etc….
Relative GWP
Impact Reduction
Current Research Has Provided Three Key Insights
Incorporating uncertainty
facilitates robust decisionmaking
A full life cycle perspective is
important
Uncertainty approach
illuminates key drivers of
differences in designs
Case study: dry no-freeze urban interstate HW in Arizona
AC
PCC
2.5” Asphalt Surface
3” Asphalt Inter.
11.0” JPCP
w/ 1.5 in Dia Dowels
8.0” Base
6.0” Agg Subbse
12” Agg subbase
Subgrade
Subgrade
ADOT Rehabilitation Schedule
and
MEPDG Rehabilitation Schedule
Parameter
AADTT two Directions
Number of Total
Lanes-two Directions
AADTT Linear Annual
Increase
Climate: dry no-freeze
Soil Type
Value
8000
vehicles/day
6
3%
AZ
A-2-6
Functional Unit:
1 center-lane mile over a 50year analysis period
Is the difference statistically significant?
4.0E-04
PDF
3.0E-04
AC PC
C
2.0E-04
1.0E-04
0.0E+00
0
5
10
15
20
Global Warming Potential (Mg CO2e/km)
PCC
The difference is
statistically significant
Frequency (%)
18%
25
X 1000
AC
Comparison
indicator :
𝛼≈0.96
15%
𝐶𝐼𝐺𝑊𝑃 =
12%
9%
𝑍𝐺𝑊𝑃,𝑃𝐶𝐶.
𝑍𝐺𝑊𝑃,𝐴𝐶.
𝛼 = 𝑃 𝐶𝐼𝐺𝑊𝑃 < 1
6%
3%
0%
0.5
0.6
0.7 0.9 1.0 1.1
CIGWP=ZGWP,Conc./ZGWP,Asph
1.2
a% of the time PCC has
lower impact
Hypothetical Situation
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4-Lane Collector Street w/Center Turn Lane
Between Two New Subdivisions
About a Mile in Length
Owner Must Make a Decision Regarding
Pavement Cross Section to Select
Must Equally Consider:
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Life Cycle Costs
Environmental Impacts Over the Long-Term
Owner is Risk Averse (i.e. does not take risks)
Decision Time…
Pavement Options
1
PCCP
Granular Base
2
PCCP
3
4
HMAC
HMAC
Cement Base
Granular Base
Granular Base
50% Confidence
LCCA (NPV) $ 3,156,700.00
LCA (tons CO2e/mi)
1,587
$ 3,115,700.00
1,762
$ 2,998,300.00
1,632
$ 2,889,450.00
1,827
95% Confidence
LCCA (NPV) $ 3,193,500.00
LCA (tons CO2e/mi)
2,103
$ 3,168,400.00
1,901
$ 3,503,250.00
2,108
$ 3,389,300.00
2,091
Conclusions
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Life Cycle Assessment is being adopted
Use Phase Impacts outweigh pre-use phase
impacts
Concrete systems perform well compared to
steel and wood over a building life cycle
Thermal mass helps reduce energy
consumption
Thank You
www.nrmca.org/sustainability