Exploring the Mechanical Properties of Green Concrete

In the January 2007 issue of the Journal of the Mechanics and Physics of Solids, an MIT research team led by Professor Franz-Josef Ulm of CEE, reported that the source of concrete's strength and durability lies in the organization of its nanoparticles. That discovery could one day lead to a major reduction in carbon dioxide emissions during manufacturing, which make up a 5 to 10 percent of the world's total CO2 emissions. "If everything depends on the organizational structure of the nanoparticles that make up concrete, rather than on the material itself, we can conceivably replace it with a material that has concrete's other characteristics-strength, durability, mass availability and low cost-but does not release so much CO2 into the atmosphere during manufacture," said Ulm. In an article published later that year in the Journal of American Ceramic Society, a team of six MIT co-authors wrote: "Concrete, bone and shale have one thing in common: their load-bearing mineral phase is a hydrated nanocomposite. Yet the link between material genesis, microstructure and mechanical performance for these materials is still an enigma that has deceived many decoding attempts... In this article, we advance statistical indentation analysis techniques that make it possible to assess, in situ, the nanomechanical properties, packing density distributions and morphology of hydrated nanocomposites."

News release about green concrete

"Statistical Indentation Techniques for Hydrated Nanocomposites: Concrete, Bone and Shale," by Franz-Josef Ulm, Matthieu Vandamme, Chris Bobko, Jose Alberto Ortega, Kuangshin Tai and Christine Ortiz. Journal of the American Ceramic Society, Sept. 2007