Tag Archives: concrete

Barrier, heal thyself

Add some bacteria to your concrete mixture, and you get walls that heal themselves:

The researchers found just the right candidates: a hardy bunch of spore-forming bacteria belonging to the genus Bacillus that make a great living in the alkaline soda lakes of Russia and Egypt. Jonkers and his colleagues placed the spores and their food source, calcium lactate, into small ceramic pellets to prevent them from being activated prematurely by the wet concrete mix and adversely affecting the integrity of the material. The spores remained dormant until the formation of a crack allowed water to sneak in, waking the bacteria and their appetite. As they began to chow down, gobbling up the calcium lactate and water, they also began to pump out calcite (a very stable form of calcium carbonate), which quickly went to work filling up the holes. Now that they’ve successfully tested the bacteria’s mettle, Jonkers and his co-workers plan on comparing the strength of their natural concrete to that of the real thing.

Regular readers may remember that this is an idea we’ve seen before.

Flexible concrete

flexible self-healing concreteI try to avoid doing posts that just go along the lines of “hey, look – cool invention!”, but I thought flexible self-healing concrete was interesting enough to warrant a bending (arf!) of the rules

A handful of drizzly days would be enough to mend a damaged bridge made of the new substance. Self-healing is possible because the material is designed to bend and crack in narrow hairlines rather than break and split in wide gaps, as traditional concrete behaves.

“It’s like if you get a small cut on your hand, your body can heal itself. But if you have a large wound, your body needs help. You might need stitches. We’ve created a material with such tiny crack widths that it takes care of the healing by itself. Even if you overload it, the cracks stay small,” said Victor Li, the E. Benjamin Wylie Collegiate Professor of Civil Engineering and a professor of Materials Science and Engineering.

Ten kudos points and a Futurismic gold star to the first commenter with either a potential disaster scenario involving flexible concrete, or a design-fiction repurposing of it. Go! [via Technovelgy]


substrate_printDevotees of rapid prototyping technologies like the RepRap Project will be pleased to hear that construction equipment manufacturer Caterpillar is funding research into scaling the technology up so that it can be used to produce concrete structures:

Behrokh Khoshnevis, a professor in the USC Viterbi School of Engineering, says the system is a scale-up of the rapid prototyping machines now widely used in industry to “print out” three-dimensional objects designed with CAD/CAM software, usually by building up successive layers of plastic.

Instead of plastic, Contour Crafting will use concrete,” said Khoshnevis.

I suppose that rapid prototyping technologies are going to be a change of web/Internet/genetic engineering proportions over the next couple of decades, affecting everything and leading to unpredictable social changes.

[story on Physorg][image from jared on flickr]