The need to decrease energy usage and subsequent emissions from the building sector has been at the forefront of U.S. green movement. Not only has energy reduction been viewed as a step for improving the environment, it has financial benefits for companies and homeowners.
To address this, researchers at the Massachusetts Institute of Technology’s (MIT) Concrete Sustainability Hub conducted a life-cycle assessment (LCA) study to evaluate and improve the environmental impact and study how the “dual use” aspect of concrete – its ability to offer a durable structure while providing thermal mass benefits for energy loads – affects the environmental footprint of the structure.
"Methods, Impacts, and Opportunities in the Concrete Building Life Cycle" provides a comprehensive analysis that advances three key areas relevant to the buildings LCA field: methodology, benchmarking, and impact-reduction opportunities. The study is a major development for construction-related life-cycle assessment because it thoroughly examines all phases of the complete life cycle of a building – from acquisition of materials to construction, the use of the building, and finally demolition and end of life.
“Most environmental assessments do not move beyond the construction phase and only provide a partial picture of the full impact a particular material can have on a building. This is short-sighted,” David Shepherd, director of sustainable development for the Portland Cement Association (PCA) said. “The heating, cooling, and general operations of buildings and homes in the United States accounts for approximately 70 percent of national energy consumption each year and an accurate LCA needs to include the operational phase.”
Concrete, essential for the construction of buildings and homes, has largely been chosen as a building material for its structural properties rather than its energy-saving properties. Although sustainable builders have known the thermal mass attributes of concrete significantly reduce heating and cooling needs, the energy consumption required to produce its key ingredient, cement, has raised questions about its environmental viability.
In its environmental assessment, MIT researchers found concrete homes produce lower greenhouse gas emissions than current best practice code – compliant wood-frame residences throughout a 60-year service life.
Concrete homes did have a higher embodied global warming potential (GWP) associated with the pre-use phase of LCA when raw materials are harvested and turned into construction materials, transported to the site, and assembled into the finished home. However, this phase accounts for only about 2 to 12%of the overall global warming potential for the life of the home. For the 60-year period of the study, houses constructed with insulated concrete forms have 5 to 8 percent lower GWP than current code compliant light frame wood houses, based on greater thermal mass and higher R-values. Researchers found similar results when evaluating multifamily residences.
Commercial office buildings built with a concrete structural frame produce slightly less greenhouse gas emissions over a 60-year service life than commercial structures built with steel frames, based on the results of the comprehensive MIT assessment.
MIT researchers then evaluated strategies to lower a concrete building’s carbon footprint and overall environmental impact. A major advancement was the incorporation of a cost-impact analysis to determine whether or not a given environmental reduction strategy made economic sense. Among the strategies evaluated, the two that reduced embodied emissions – increased fly ash and reducing the thickness of concrete walls from a 6-inch to a 4-inch concrete core – were found to be both economical and effective ways to reduce emissions. BD+C
Related Stories
| Oct 23, 2013
AIA: Crowd-funding shows promise for financing real estate projects
The American Institute of Architects issued a statement on the SEC's recent 5-0 vote to propose rules aimed at letting startups tap large numbers of ordinary investors for small amounts of capital.
| Oct 23, 2013
Gehry, Foster join Battersea Power Station redevelopment
Norman Foster and Frank Gehry have been selected to design a retail section within the £8 billion redevelopment of Battersea Power Station in London.
| Oct 23, 2013
Some lesser-known benefits of metal buildings
While the durability of metal as a construction material is widely recognized, some of its other advantages are less commonly acknowledged and appreciated.
| Oct 23, 2013
Architecture Billings Index hits seven-month high in September
AIA's Architecture Billings Index was 54.3 in September, the highest level since February 2013
| Oct 18, 2013
Meet the winners of BD+C's $5,000 Vision U40 Competition
Fifteen teams competed last week in the first annual Vision U40 Competition at BD+C's Under 40 Leadership Summit in San Francisco. Here are the five winning teams, including the $3,000 grand prize honorees.
| Oct 18, 2013
A picture’s worth a thousand words… if you can find it
Photographs are becoming more essential to project communication and documentation. Recently, I sat in a local airport integration project meeting in which the owner outlined their expectation for construction documentation. One of the first requirements was to provide photographs throughout the building process.
| Oct 18, 2013
Researchers discover tension-fusing properties of metal
When a group of MIT researchers recently discovered that stress can cause metal alloy to fuse rather than break apart, they assumed it must be a mistake. It wasn't. The surprising finding could lead to self-healing materials that repair early damage before it has a chance to spread.
| Oct 18, 2013
Call for submissions: AIA Emerging Professionals Summit essays
The American Institute of Architects (AIA) is seeking essays that will address what role architects will play in society in 2033.
| Oct 16, 2013
5 secrets of successful entrepreneurs
If you’re on the outside looking in, successful entrepreneurship may seem mysterious. But it isn’t. Here are five patterns of behavior that are common to successful entrepreneurs.
| Oct 15, 2013
High-rise Art Deco courthouse gets a makeover in Amarillo, Texas
Recognized as one of the most significant Art Deco courthouses in Texas, the Potter County Courthouse is modernized and restored to its 1930s aesthetic.