Re: Steel re-bar in concrete

[Rick Lucertini <empiricus@sprint.ca>]

DaveIrons@aol.com wrote:

> [snip]
> 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.
>
> David Irons

That sounds nasty.  It reminds me of the force of freezing water expanding.  Farmers
used to pour water into the cracks of boulders on their farms during winter months so
that the expanding water/ice would fracture the rock into smaller manageable
fragments.

>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.

If you put the re-enforcement inside the hull, would it help eliminate thru hull
support members?  Wouldn't putting the re-enforcing members outside the hull require
fittings to protrude, and therefore create areas of potential weakness in the hull?
This would require extra design work and testing.  Unless, of course, you need the
extra room inside for equipment, life support, etc.

The unpredictability of it certainly eliminates rebar.  The poly mixes were, if I
remember correctly, much more predictable in failure?

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