On Thu, 17 Feb 2011 10:45:41 -0000, "anon and off"
wrote:

During the recent cold spell, I kept a footpath's width along
the driveway clear by copious amounts of cooking salt.

Now, although the rest of the concrete has 56 years' of
grey drabness and growth (which you could "liken" to a moss)
the bit that I kept clear is yellowish and crumbling.

I wonder if anyone here has the chemical reaction info, or
similar experiences?

Have a look at

http://www.ehow.co.uk/how_6382604_re...-concrete.html