Concrete creeps. And now scientists think they know why.
![](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2009/06/10577.jpg?resize=300%2C217&ssl=1)
New measurements suggest that the rearrangement of nano-sized concrete particles is responsible for the way buildings, bridges and other load-bearing concrete structures deform over time, a process technically known as “creep.” The new insight could allow engineers to make stronger and longer-lasting concrete, researchers report in a study to be published online in the Proceedings of the National Academy of Sciences.
Creep limits the life span of a building or bridge, deforming its structure and leading to instability, says Franz-Josef Ulm of MIT, a coauthor of the study. “It’s a little like chewing gum,” Ulm says. Gum will stretch and compress if a constant force is applied. “Concrete does exactly that, but at a much larger scale.”