U-M researchers make bendable concrete

University of Michigan ^ | 04 May 2005 | Laura Bailey

[ctlpdad]

It's not hard to make an unsinkable concrete canoe. I did in college. We used a cement, water, polymer & glass bead aggrate mix that had a unit wieght less than water, so it floated without any added foam floatation necessary. It was also 12,000 psi, about 3 times as strong as the concrete used for house foundations, and was also relatively flexible.

The glass beads and the polymer made the big difference. The beads are the same used in the road line striping paint to provide the reflective quality.

Last I knew, several school, especially University of Alalbama, Huntsville, were using carbon fiber reinforcing and space age polymer "concete" at about 3/8" thick to make canoes that were lighter than any commercially available canoes.

[jigsaw]

Unreal! Thanks.

[Kozak]

would be worth it in earthquake country. Think Cypress Freeway in 89

[buridan]

A bend in the road can finally be a bend in the road.

[aposiopetic]

While long-term studies are still needed, comparison studies by the School of Natural Resources and Environment's Center for Sustainable Systems, in conjunction with Li's group, show that over 60 years of service on a bridge deck, the ECC is 37 percent less expensive, consumes 40 percent less energy, and produces 39 percent less carbon dioxide (a major cause of global warming) than regular concrete. The study notes that the findings are based on the assumption that ECC lasts twice as long as regular concrete, a reasonable assumption given the known information, but it must be confirmed through further study.

So if they last the same amount of time, is ECC 26% more expensive and does it consume (?) 20% more energy than regular concrete?

[1john2 3and4]

Excellent! I remember seeing a video of a Coast Guard boat plowing into monster waves offshore. Thing would go belly-up, then pop around and right itself.

So the dream was to build a sailboat with the same characteristics....and having read about "rogue waves" (on Free Republic of course!), plus the danger of ramming something, or being rammed, I thought the ferro cement concept would be the ultimate in safety. Not surprised that the aggregates & polymers have advanced in the years since. FRegards,
john

[Ichneumon]

Science ping?

[ctlpdad]

Well, the coast guard 44 footers, and now the new 47' motor life boats work on a different principle. The engines are low in the hull, and they require the watertight compartments be sealed by the hatches before going out into the rough seas.

That is some serious extreme sailing you want to do where you get smashed by a wave so bad you would roll aover like that, and potentially bump into stuff. What do you plan to use for a mast? I might suggest 6" diameter, 3/4" wall weathering steel tube.

A weighted keel and a fiberglass hull might work out better for your intended application.

[jimfree]

Wow!

[PatrickHenry]

Not really. It's darned interesting, but I've been using the science list mostly for cosmology, physics, etc. This is way far from that, and the listees didn't sign on for engineering improvements. So I gotta pass.

(PatrickHenry, the sensitive ping list keeper.)

[G Larry]

Would be a best seller in bentonite soil areas like Denver suburbs.

[concrete is my business]

Please excuse my very late reply. I have been away from computers for the last 3 weeks!

The part that I find most interesting in this new concrete development is the difference in the weight. That alone could save alot of work and money.

Also since concrete is very strong in vertical compression and weak and brittle horizontally, this could help prevent cracking, but concrete slabs are only as good as what is under them and IMO that will always be true.

[Final Authority]

Transparent aluminum or crystalline Al2O3, also known as synthetic sapphire has been in existence for decades. It is the watch crystal for good to expensive watches, it is the window on the grocery store scanner, it is the detector window for MWIR instrumentation and is used as all sorts of optical components in military optics.

The article you cite talks to a cheaper way to make an inferior product. As soon as it is doped with the rare earth elements it becomes less useful as an IR optic material.

[the invisib1e hand]

we are the children of concrete and steel...
everything is possible but nothing is real...

Living Colour, Concrete and Steel.