What happens to Aluminium in Autoclaved Aerated Concrete
$$\ce{2Al + 7Ca(OH)2 -&gt; Ca[Al(OH)4]2 + 3H2 ^ + 6CaO}$$ 
or maybe 
$$\ce{2Al + Ca(OH)2 + 6H2O -&gt; Ca[Al(OH)4]2 + 3H2 ^}.$$
I think you'd get basically (ha) aluminium hydroxide.  This is effective because bases can dissolve the protective aluminium oxide layer that usually protects aluminium metal from corrosion.  The concrete is foamed by the hydrogen.