Smart Flexible Cement
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....from an abridged Press Release
"....A new type of cement could make buildings that can better withstand earthquakes and highways with fewer potholes.
It Bends, But It Doesn't Break
Each year, something in the range of 500,000 detectable earthquakes shake the four corners of the earth. About 100,000 of those can be felt, and around 100 of them, with about as much energy as an atomic bomb, cause real damage. Often, the real danger from earthquakes is from things that break apart and fall down when the earth starts to tremble.
Without warning a rumble builds and the room begins to shake. Buildings sway in unnatural ways, waves rock and warp groaning bridges, and the ground shifts beneath you.
EEC
But, engineers at the University of Michigan in Ann Arbor have developed a bendable, or ductile, concrete-like material that can withstand the severe stress, or "loading," that happens when an earthquake hits.
"It can carry the load without creating the typical type of failure that we observe now-a-days in buildings under severe loading,"
This high-tech smart concrete slurry, called Engineered Cement Composite (ECC), can be mixed and applied using traditional methods for concrete, but it is stronger, longer lasting, lighter, more flexible and less likely to crack than the concrete generally used to build roads, bridges and building.
Traditionally, the usual mix of cement, water and sand or gravel is reinforced with metal rods or bars to provide the strength needed for bridges and buildings. This new smart concrete-like composite looks like regular concrete, but incorporates super fine (100 microns in diameter) silica sand, and tiny plastic — polyvinyl alcohol or PVA — fibers covered with a very thin, nanometer-thick, slick coating.
PVA
"This surface coating allows the fiber to begin slipping when they are over loaded so they are not fracturing. It prevents the fiber from rupturing which would lead to large cracking,"
"[ECC] can deform much more than normal piece of concrete without fracturing into pieces."
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Under intense strain, the fibers slide within the concrete, giving under the pressure rather than breaking apart. The fibers behave somewhat like your body's ligaments, holding things together in a flexible manner.
More than that, the different components work together to share the load.
"They essentially collaborate, if you will, so that when the material is overloaded they provide a give in transferring the load elsewhere to its neighbor, so its neighbor also helps in supporting the load,"
In lab tests the ECC proved to be 500 times more flexible than traditional concrete, and 40 times lighter.
Cost: The new cement costs three times the price of regular concrete, but because it's so forgiving builders can use much less of it, and since it's so durable, maintenance will cost less.
ETA : 2005 The material is already being used in earthquake-prone areas of Japan and Korea, and is set to make it's American debut in fall, 2005 on a section of the Grove Street Bridge in Ypsilanti, in Michigan.
Funding: This research was funded by Michigan Department Of Transportation and the National Science Foundation.
Level: Intelligence Level (1) Adapting: Modifying Behavior to React to/Fit the Environment
Status: working lab prototype and commercial version
What do you think of this smart technology ? Pros or Cons? Impacts?
Walter Derzko
Expert and Guest Speaker on the Smart Economy and author of an upcoming book on the Smart Economy
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