Tuesday, March 6, 2012

Ultra-high performance concrete


ultra-high performance concrete -
Iran is an earthquake zone, so its engineers have developed some of the toughest building materials in the world. Such materials could also be used to protect hidden nuclear installations from the artificial equivalent of small earthquakes, namely bunker-busting bombs.

Leon Panetta, America’s defence secretary, seems worried. He recently admitted that his own country’s new bunker-busting bomb, the Massive Ordnance Penetrator (MOP, pictured above being dropped from a B-52), needs an upgrade to take on the deepest Iranian bunkers. But even that may not be enough, thanks to Iran’s mastery of smart concrete.

UHPC is based—like its quotidian cousins—on sand and cement. In addition, though, it is doped with powdered quartz (the pure stuff, rather than the tainted variety that makes up most sand) and various reinforcing metals and fibres.

UHPC can withstand more compression than other forms of concrete. Ductal, a French version of the material which is commercially available, can withstand pressure many times higher than normal concrete can. UHPC is also more flexible and durable than conventional concrete. It can therefore be used to make lighter and more slender structures.

One way to tamper with the internal structure of concrete is to use nanoparticles. Ali Nazari and his colleagues at Islamic Azad University in Saveh have published several papers on how to do that with different types of metal-oxide nanoparticles. They have worked with oxides of iron, aluminium, zirconium, titanium and copper. At the nanoscale materials can take on extraordinary properties. Although it has been demonstrated only in small samples, it might be possible, using such nanoparticles, to produce concrete that is four times stronger than Ductal.

http://www.economist.com/node/21548918?fsrc=scn/fb/wl/ar/smartconcrete

Are Indian firms really going to take over the world? - http://www.economist.com/node/21548965?fsrc=scn/fb/wl/ar/runningwiththebulls