MIT Concrete Sustainability Hub
Bruce McIntosh, Portland Cement Association
Topics
• HUB background
• Life-cycle assessment of pavement
• Life-cycle assessment of buildings
and homes
• Econometrics
• Green concrete science
MIT Concrete Sustainability Hub
• Established by PCA and RMCREF
• $10 million investment over next 5 years
• Validate and innovate:
– Identify areas in which concrete excels
– Identify opportunities for improvements
– Create solid technical basis for future
industry development
R&D Platforms
• Concrete Science
• Building Technology
• Econometrics
Concrete Science Platform
• Mission: Scientific breakthroughs
toward reducing CO2 footprint of
cement and concrete
• Breakthroughs would imply:
– Strength with less material
– Lower energy processing
– Chemical stability
Building Technology
Platform
• Mission: Life-cycle assessment
(LCA) of concrete buildings and
pavements to identify impacts and
opportunities
Econometrics
• Mission: Assess the impact on jobs
and the economy of sustainable
advancements in cement and
concrete
Building Technology: Paving
• 8 million lanemiles
• 3 trillion vehiclemiles / year
• 27% of U.S. GHG
emissions from
road transportation
Improving Paving
Performance
• Comprehensive
methodology for pavement
LCA
• Quantifying greenhouse
gases
• Investigate pavementvehicle interaction
Life-Cycle Analysis
Opportunities from LCA:
• “Cradle-to-cradle” analysis
• Large impacts beyond initial
manufacturing
• Use-phase impacts
Use-Phase Impacts
•
•
•
•
Fuel consumption
Urban heat islands
Street lighting
Carbonation
Indirect impacts
• Traffic delays
• Additional materials and energy
• Construction equipment emissions
• Material waste
Key findings
• Whole life LCA needed to capture all
impacts
• Use and maintenance phases account
for 33% to 44% of CO2 for interstate
highways
Pavement-Vehicle
Interaction
• Demonstrates of fuel savings with
concrete
• Two factors: stiffness and roughness
Stiffness
Roughness
Stiffness or Deflection
• Rigid pavements produce less rolling
resistance and better fuel economy
Stiffness
Stiffness or Deflection
• Asphalt roads need to be 25% to 60%
thicker to achieve same fuel efficiency
as concrete.
• Goal is to assess impacts of pavement
properties on fuel consumption for both
environmental impact and cost
savings.
50-year GHG Emissions
PVI (Deflection)
Production + M&R
GHG Emissions (Mg
CO2e)
2500
2000
1500
1000
500
0
Concrete
Asphalt
High Volume
Concrete
Asphalt
Arterial
Building Technology:
Structures
• Life-cycle analysis research for
single-family housing, multifamily
housing, and commercial structures
Why are Buildings
Important?
56%
25%
18%
Commercial Bldgs
21%
Residential Bldgs
26%
Transportation
19%
35%
United States
Other of G7 countries
Rest of the world
Industry
Buildings Life-Cycle Analysis
• Examining materials within whole building
context, not just manufacturing and initial
construction
• Consider use and operations phases
Single-Family Housing
• Single family homes represent 80% of
total residential energy consumption
Multi-family
80%
Single family
Single-Family LCA
• Exterior walls
• Wood frame and
insulating concrete
forms
• Quantity of insulation
• Thermal mass
Key Findings
• Concrete homes produce 5% to 8%
lower GHG emissions.
• Concrete homes use 8% to 11% less
energy.
• Concrete wall systems have higher
embodied energy, but that accounts
for only 2% to 12% of GHG over a
60-year service life.
Next Steps: Air Tightness
• Not considered in initial study, but
represents greatest potential for
additional improvement
• Improvement from average to tight
saves 23% of total operating energy
Commercial Buildings
• Commercial buildings represent
18% of U.S. energy consumption
Commercial LCA
• Compares steel and
concrete structural
frames
• Floor to floor heights
identical
• 12-story building with
40% glazing
Key Findings
• No greater embodied energy than
comparable steel frames
• Energy savings when concrete
frame is exposed are 3%; when
covered by finishes, 2%.
• Active use of the thermal mass
capability of concrete slabs could
result in significant savings
Econometrics
• Study on life-cycle cost analysis” for
highways, “The Effects of Inflation
and Its Volatility on the Choice of
Construction Alternatives.”
• Study examines historical data on
real prices of construction materials.
Key Findings
• Traditional analysis uses the same
escalation rate for concrete and
asphalt .
• Assumption of constant real costs
can lead to serious cost overruns.
• Study suggests the use of materialspecific escalation rates.
Advocacy and Promotion
• Working with state and federal
officials to incorporate MIT findings in
life-cycle analysis models
• Focus of ad campaign
• Goal: Level playing field for concrete
and asphalt.
Ad Campaign
Concrete Science Platform
1. Alite/belite
reactivity
2. Aluminate reactivity
3. Alkali effects
4. Water and
dissolved
components
5. Mechanical
properties of
materials
Concrete Science Platform
• Industry/MIT collaboration
• Significant progress on key topics:
– Alite/belite reactivity
– Water and dissolved components
– Mechanical properties of materials
More Information
• http://web.mit.edu/cshub/
MIT Concrete Sustainability Hub
Bruce McIntosh, Portland Cement Association