One group of engineers at MIT decided to focus its work on the nanostructure of concrete, the world’s most widely used material. The production of cement, the primary component of concrete, accounts for 5 to 10 percent of the world’s total carbon dioxide emissions; the process is an important contributor to global warming.
Cement is manufactured at the rate of 2.35 billion tons per year, enough to produce 1 cubic meter of concrete for every person in the world. If engineers can reduce carbon dioxide emissions in the world’s cement manufacturing by even 10 percent, that would accomplish one-fifth of the Kyoto Protocol goal of a 5.2 percent reduction in total carbon dioxide emissions.
If the researchers can find-or nanoengineer-a different mineral to use in cement paste, one that has the same packing density but does not require the high temperatures during production, they could conceivably cut world carbon dioxide emissions by up to 10 percent.
This aspect of the work is just beginning. Ulm estimates that it will take about five years, and says he’s presently looking at magnesium as a possible replacement for the calcium in cement powder. “Magnesium is an earth metal, like calcium, but it is a waste material that people must pay to dispose of,” he said.