Al - Cement

[mcollins07]

While goggling for ferro-cement info I saw that expanded aluminum had been used as a lath in cement laminates for house construction. For boats, I suspect the aluminum core will eventually get exposed and corrode in salt water, but was wondering if there were real world attempts. Anyone know of Al lath being used in boats?

Know of any surface treatments for the Al to enhance adhesion to the cement? I speculate that a CaO wash of the aluminum would produce a Al2O3 surface which would enhance the cement bond. An anodized phosphate wash might be interesting to try also.

[DrCraze]

Aluminum reacts heavily with cement creating gas bubbles within during the cure cycle. I wouldn't recommend using aluminum in ferro for that reason. I suppose you could coat it first as I do with any galvanized lath. Galvanized lath react with cement as well but to a lesser degree.

[mcollins07]

Originally Posted by DrCraze

Aluminum reacts heavily with cement creating gas bubbles within during the cure cycle.

Ah yes, that is a good point DrCraze. The alkaline solution should produce hydrogen gas, and a good amount as long as it is wet.

What do you coat your galvanized materials with?

[DrCraze]

I use acrylic based concrete adhesive over anything with zinc in it but aluminum I use a polyacrylic clear coat to be sure I isolate it 100%.

[mcollins07]

Thanks for that info DrCraze.

[LyndonJ]

Don't
The temperature expansion ratios are completely incompatible too (between the cement/concrete and the mesh)