Concrete in Saltwater

[Flyboy]

G'day,
Just wanted to ask what extra steps/precautions are needed when concreting in saltwater, in particular to prevent the reo corroding. Need to lay a small slab (about 1000x1200x200) which will be exposed only at lowtide.
I would have guessed something like using galvanised reo but someone was telling me that in saltwater, gal is actually worse:confused::confused::confused:
Cheers

[TEEJAY]

The concrete code AS3600 - 2001 says high strength concrete with plenty of cover - so minimum 50MPa concrete and minimum 50mm cover to the reo.

Ensure good compaction of the concrete - you can use a prodder and poke vigorously to remove any entrapped air.

If you want to do more you can always paint the surface of the concrete with a waterproof membrane to prevent the ingress of water and salts.

[Flyboy]

Thanks Teejay,
Are there additives you can get which will stop the saltwater penetrating the concrete? And would that be standard reo or galvanised reo to use?
Cheers

[attie]

Hi Flyboy, I've done a fair bit of concrete work in salt water, I've actually poured concrete under water by displacing the water with concrete. Do what TEEJAY says and have plenty of cover and get the air out of it, I have always used 30mpa with about 25mm slump. I don't think there is any need for any additives and standard reo is fine