Concrete is brittle, only a small amount of sudden force is necessary to fracture 1/2" of concrete. A latex additive increases the strength and toughness significantly. Fiberglass fibers also increase the strength like cement board used for showers and tile underlayment.

A tornado can exert in excess of 5 psi on a wall. Given 16" studs and an 8 foot wall; each stud would have to resist 8 x 12 x 16 x 5 = 7,680 pounds of lateral force. The 1/2" cement board would buckle under that force, let alone unreinforced concrete.

Nanotube fibers could very well make your idea practical and desireable. Nanotubes are over 1000 times stronger than steel. But currently they are cost prohibitive.

I'm sure in some applications precast concrete is less expensive because of labor and performance requirements.

Thanks for your input. However, perhaps you have never heard of "ferrocrete".They even use it to build ships.I have been following its development for over thirty years.It is made by a different method than ordinary steel reinforced concrete.

One might compare it this way: Take fiberglas products where let's say we call the resin the "binder" and the glass fibers the "fillers". Now, let's substitute the product make-up to "ferrocrete" where cement (concrete) is the "binder" and steel mesh is the "filler". There are several instances on the web that fall under that description. I, myself have seen one ship on the Gulf Coast made this way. I've also seen demonstrations of car fenders made of this where a sledge hammer bounced right off it when struck. The steel-to-concrete ratio is much higher than in ordinary concrete.

The process has been around for almost one hundred years.

The problem in making it a success it seems, is casting the item you want to make in one giant piece.

My design calls for a completely different method of fabrication. A secret method using pre-fab construction - joining piece after piece in a special way so one can fabricate a giant dome using thousands of smller parts.

Please look it up on the web. It's a fascinating subject!

By the way, I've read about the "nano tubes" and I concur with you. One day, when the costs come into line with the need it'll be a "whole 'nother" ballgame.

Bill Claborn