PIs: John Ochsendorf , Les Norford , and Timothy Gutowski

1. The Edge of Concrete: A Life Cycle Investigation of Concrete and Concrete Structures PIs: John Ochsendorf, Les Norford, and Timothy Gutowski September 13, 2010

3. Motivations for LCA work Growing demand for quantifying performance of structures Industry Day – August 31, 2010

4. Motivations for LCA work Growing demand for quantifying performance of structures Industry Day – August 31, 2010

5. Motivations for LCA work • Growing demand for quantifying performance of structures 2030 Challenge calls for carbon reductions of: 60% in 2010 (of average carbon emissions for building type) 70% in 2015 80% in 2020 90% in 2025 Carbon-neutral in 2030 Industry Day – August 31, 2010

6. Motivations for LCA work Growing demand for improved quantification of green building 2030 Challenge calls for: 60% in 2010 (of carbon emissions 70% in 201580% in 202090% in 2025 Carbon-neutral in 2030 Industry Day – August 31, 2010

7. Motivations for LCA work Growing demand for quantifying performance of structures Increasing recognition that green design includes the construction phase and the operating phase of buildings Industry Day – August 31, 2010

8. Motivations for LCA work Growing demand for quantifying performance of structures Increasing recognition that green design includes the construction phase and the operating phase of buildings Advantages of concrete construction in lowering the emissions in the operating phase Industry Day – August 31, 2010

9. Goals of LCA Project Identify advantages over full life cycle Identify areas for improvement Build foundations for future studies Industry Day – August 31, 2010

10. 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 Industry Day – August 31, 2010

11. Pavements: Locations and Materials • Concrete versus asphalt roads • Analysis currently based on national averages • Concentrating on high-volume highways Industry Day – August 31, 2010

12. Roadway lighting, lane closures, etc.

13. Model Scenarios High volume road: Route 101 in Oxnard, CA (at Route 232 junction) 65 mph highway 3 lanes each direction + 4 shoulders Daily traffic: 139,000 (Of which trucks: 6,672) Moderate volume road: Route 67 in Ramona, CA (at Route 78 junction) 35 mph urban road 2 lanes in each direction + 4 shoulders Daily traffic: 23,400 (Of which trucks: 1,357) Low volume road: Route 178 in Sequoia National Forest 35 mph rural road 1 lane in each direction Daily traffic: 5,200 (Of which trucks: 468)

14. Full Life Cycle Emissions for Different Traffic Volumes

15. In Summary • Concrete production emissions are higher than asphalt, but concrete use phase emissions are lower • High traffic volume concrete highways can have up to 90% 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 inaccurate • No one has accurately quantified their interactive effects, the effect of each pavement layer, nor the effect of temperature.

16. Work for Year Two • Refine our fuel consumption models to better account for pavement-vehicle interactions and to instill greater confidence in fuel savings due to pavement design. • Continue 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.

17. Buildings: Locations Phoenix Chicago We consider two climate regions in the US We will expand the studies to other cities Industry Day – August 31, 2010

18. LCA Components Pre-use phase Use phase End of life Extraction Heating Disposal Manufacturing Cooling Recycling Transportation Lighting Reuse Concrete Fans Transportation Steel Plug loads Insulation Maintenance Glass Energy Mix Industry Day – August 31, 2010

19. Commercial Buildings • Reinforced concrete frames versus structural steel frames in: • 12-story commercial office buildings Industry Day – August 31, 2010

20. Results CHICAGO PHOENIX Total HVAC: - 5% Chicago - 6% Phoenix Industry Day – August 31, 2010

21. Results Chicago - 2.5% Phoenix - 2.7% Industry Day – August 31, 2010

22. Results Thermal mass provides energy savings over time Better estimation needed of concrete recycling rates and end-of-life emissions Even greater advantages are possible for concrete buildings Industry Day – August 31, 2010

23. Next Steps • Passive strategies • Night cooling • Passive solar heating • Active strategies • Radiant systems • Low-lift cooling • “Predictive Pre-Cooling Control for Low Lift Radiant Cooling using Building Thermal Mass” by N. Gayeski, 2010 • Envelope systems Industry Day – August 31, 2010

24. Residential Buildings • Insulated concrete form (ICF) structures versus wood frames in: • Two-story single-family residences • Four-story multi-family residences Industry Day – August 31, 2010

25. RESULTS: Single Family Operational Energy Chicago - 34% Phoenix - 6.3% • Results based on average quality wood construction, insulated to meet code vs. typical ICF quality construction • Primary research performed to determine air-tightness of ICF construction • MIT sponsored tests on 15 ICF houses around the country

26. Conclusions • ICF homes deliver substantial energy savings over the lifetime of residential buildings • Blower door testing revealed that ICF homes offer tight construction with improved energy performance • Significant further improvements can be made to the life cycle performance of ICF homes

27. Highlights of LCA Studies in Year One For a high traffic volume highway, the greater fuel efficiency of vehicles driving on concrete pavements can lead to significantly lower carbon emissions compared to an asphalt pavement. Over a 50-year lifetime, the savings could be as high as 90% of the carbon emissions associated with the pavement selection. For commercial buildings, the higher thermal mass of concrete buildings can offer savings of 6% of the heating, ventilation and cooling (HVAC) energy consumption for a hot climate such as Phoenix, and 5% of HVAC energy for a cold climate such as Chicago, compared to steel construction. Even greater reductions (up to 25% of operating energy) are possible through improved design of concrete commercial buildings. For residential buildings, insulated concrete form (ICF) construction can offer HVAC energy savings of 30% or more compared to code compliant wood-framed buildings in a cold climate such as Chicago. Such operational energy savings can compensate for the initial carbon emissions of the concrete within a few decades of operation. Industry Day – August 31, 2010

29. Embodied versus operating Industry Day – August 31, 2010

30. Embodied versus operating 40% reductions possible 30% reductions possible Industry Day – August 31, 2010

31. Next Steps Complete studies and write reports this fall Finalize work plans for year two Integrate new team members Industry Day – August 31, 2010

32. Thank You Industry Day – August 31, 2010