Politics.be - Milieuvriendelijk beton voor de eeuwigheid

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Milieuvriendelijk beton voor de eeuwigheid

Tegen Jehova's Armageddon
bouwt men best Wachttorens in beton.
Het nieuwste cement
blijkt uiterst potent.
Maar stopt het CERN's ontaard cyclotron ?

Eeuwig beton

Ziet er goed uit.
Een langere levensduur die ook lichtere constructies mogelijk maakt.

Citaat:

... the basic building block of cement paste at the nano-scale — calcium-silicate-hydrates, or C-S-H — is granular in nature. The paper explained that C-S-H naturally self-assembles at two structurally distinct but chemically similar phases when mixed with water, each with a fixed packing density close to one of the two maximum densities allowed by nature for spherical objects (64 percent for the lower density and 74 percent for high).

In the new research revealed in the PNAS paper, Ulm and co-author Matthieu Vandamme explain that concrete creep comes about when these nano-meter-sized C-S-H particles rearrange into altered densities: some looser and others more tightly packed.

They also explain that a third, more dense phase of C-S-H can be induced by carefully manipulating the cement mix with other minerals such as silica fumes, a waste material of the aluminum industry. These reacting fumes form additional smaller particles that fit into the spaces between the nano-granules of C-S-H, spaces that were formerly filled with water. This has the effect of increasing the density of C-S-H to up to 87 percent, which in turn greatly hinders the movement of the C-S-H granules over time.

Zie: http://www.physorg.com/news164337623.html

Uit: http://nextbigfuture.com/2009/06/mit...ete-creep.html

MIT 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 nano-scale.

The image shows the imprint left by a nanoindenter in a particle of cement paste.
The round blob at the top center is actually an extremely fine piece of dust on the surface.
Photo / Chris Bobko
.