The DNA of Concrete—No, Seriously!

By Ed Martinez

September 11, 2009

Concrete has been around for about 2,000 years. It was widely used by the Roman Empire to build a vast system of aqueducts and large buildings throughout their territories. Today, cement has become the most prevalent man-made material on earth.

The concrete industry has been under pressure in the past several years, largely due to concrete’s carbon dioxide emissions, which are responsible for about five percent of all carbon dioxide emissions worldwide. "Cement is so widely used as a building material that nobody is going to replace it anytime soon. But it has a carbon dioxide problem, so a basic understanding of this material could be very timely," said MIT Professor Sidney Yip.

Yip and his team of researchers, have managed to decode cement’s molecular structure. The recent discovery means that the chemical structure within cement can now be manipulated to design concrete for strength and environmental qualities, such as the ability to withstand higher pressure or temperature.

"We've known for several years that at the nano scale, cement hydrates pack together tightly like oranges in a grocer's pyramid. Now, we've finally been able to look inside the orange to find its fundamental signature. I call it the DNA of concrete," added Franz-Josef Ulm, the Macomber Professor in the Department of Civil and Environmental Engineering (CEE). Ulm and Yip have both authored a recent paper in the Proceedings of the National Academy of Sciences (PNAS).