CEE engineers find way to slow concrete creep to a crawl
June 15, 2009
By Denise Brehm
Civil & Environmental Engineering
MIT civil engineers have for the first time identified what causes the most frequently used building material on earth — concrete — to gradually deform, decreasing its durability and shortening the lifespan of infrastructures such as bridges and nuclear waste containment vessels.
In a paper published in the Proceedings of the National Academy of Sciences (PNAS) online Early Edition the week of June 15, researchers say that concrete creep (the technical term for the time-dependent deformation that occurs in concrete when it is subjected to load) is caused by the rearrangement of particles at the nanoscale.
“Finally, we can explain how creep occurs,” said Professor Franz-Josef Ulm, co-author of the PNAS paper. “We can’t prevent creep from happening, but if we slow the rate at which it occurs, this will increase concrete’s durability and prolong the life of the structures. Our research lays the foundation for rethinking concrete engineering from a nanoscopic perspective.”
This research comes at a time when the American Society of Civil Engineers has assigned an aggregate grade of D to U.S. infrastructure, much of which is made of concrete. It likely will lead to concrete infrastructure capable of lasting hundreds of years rather than tens, which will bring enormous cost-savings and decreased