Aerated concrete (AAC)

Aluminium comes in Update 3, so this is another good opportunity for its usage.
With aluminium can do concrete slabs with less cost.
Concrete mixer:
1.5 Cement + 1..3 Limestone + 1..3 Aluminium + 6 Water = 12 Concrete Slab

We don't know changes in recipes, but i expect aluminium to be VERY costly. Certainly not something going into concrete. But we could use alternative IRL recipes like adding rubber into it. Or forcing some gas into it (maybe CO2?) to make it lighter and thus using less resources.