Steel re-bar in concrete

[DaveIrons@aol.com]

You are correct Rick.  

Steel re-bar re-enforcement does make a pressure hull stronger under
compression about 50% stronger.  However, several of the samples imploded
unexpectedly at lower pressers, sometimes drastically lower pressures.  My
real concern with steel re-bar is rust.  In theory the re-bar will not rust
because
no oxygen is available.  When you put people inside vessel the situation may
change.  The experiments were done with unmanned concrete test spheres and
cylinders.  
When steel rusts it expands.  The rusting steel exerts an enormous force.  A
section of concrete is blown off.  Look at a concrete bridge and you will see
the effects of rusting re-bar inside concrete.  I think I'll keep the re-
enforcement outside the pressure hull, where rust will only make the paint
chip, not blow a hole in the hull.

David Irons

>As you pointed out, you discovered problems that you hadn't thought about. 
>I was surprised to discover that re-bar re-enforcement actually WEAKENS a
>concrete pressure hull.  I would have assumed the opposite.

>Rick


>Rick Lucertini
>empiricus@sprint.ca
>(Vancouver, Canada)