Research shows environmental impacts of concrete over 60 years

The Massachusetts Institute of Technology (MIT) has just published two major studies looking at the environmental and cost impacts of concrete pavements and buildings, comparing them to other materials.

Conducted at MIT by the Concrete Sustainability Hub (which is supported by the Portland Cement Association and the Ready Mixed Concrete industry), the research looked not only at the embodied CO2 of concrete vs. other materials at the initial construction stage i.e. the carbon emissions given off in manufacturing and installing the material, but also over the entire lifecycle of the material, i.e through its use and operations phases.

For highways, for example, they say that between 33 and 44 per cent of the C02 emissions over the lifetime of concrete pavement are related to the use and rehabilitation phase.

The MIT researchers researched the impacts of different paving materials and structures on vehicle’s fuel consumption. For this they used the “first ever mechanistic pavement-vehicle interaction model.” The initial tests found that “for the same stiffness and fuel consumption, an asphalt pavement had to be up to 60 per cent thicker than the concrete pavement.”

The study of buildings looked at the energy use and emissions related to concrete and other materials in single-family residential, multi-family residential and commercial buildings. They also considered the use of insulated concrete forms (ICFs) in homes.

Among the findings were that in general the total embodied global warming potential (GWP) of single-family homes built with insulated concrete forms was actually higher than that for light-frame wood houses. Over the 60-year period of the tests, however, the ICF houses have 5% -8% lower GWP than light-frame wood houses, due to their greater thermal mass and higher R-values.

For commercial buildings, the studies compared concrete and steel structural systems. They found that over 60 years, both types of buildings had an equivalent embodied global warming potential “and the choice of structural material does not dramatically influence the total emissions.”

The studies, “Methods, Impacts, and Opportunities in the Concrete Building Life Cycle” (Ochsendorf, John et al),  and “Methods, Impacts, and Opportunities in the Concrete Pavement Life Cycle” (Santero, Nicholas, et al) wer published in August.  Click here.

http://web.mit.edu/cshub/index.html