visionset wrote:
On Thu, 07 Sep 2006 11:39:19 -0700, Bookworm wrote:

Rednadnerb wrote:
Steel needs oxygen as well as water to rust. Reinforcing bars will
rust and the concrete spall if there isn't enough cover of concrete
over them or if the concrete isn't properly compacted around them.

I agree. Also concrete starts off being highly alkaline which
prevents oxidisation. However carbon dioxide in the atmosphere
penetrates the concrete at about 1mm per annum which turns it acid.
When this 'carbonation' reaches the rebar it will rust and in time
spall the concrete.

There are many ways to prevent this happening. (by the way, wire
brushing rust on MS just polishes it)

Right. Where do I get galvanised rebar from then? My BM just does the
mild steel stuff. I need about 8mts

You'll be lucky, it's as rare as rocking horse sh!t...why can't you just use
normal mild steel but treat it first with something? - this would
effectively double it's life.