Thanks Will.
If this was a rebar problem, that would apply, but, this is the base of a steel "I" beam pillar, so it's more difficult. I have reinforced with welded and bolted plates and I intend to protect the feet with concrete, but, this will only be the first 5or6 inches, so above, there's nothing and a potential damp penetration. I have found out that Phosphoric acid is used as a concrete cleaner/etcher, so I'll need to do something to separate the phosphoric acid from the concrete. I am thinking either of neutralising the acidity or simply painting to protect the concrete.
Regards, Matthew