AirCrete - lime
Is it possible to use lime instead of regular cement?
NO. You'll have very, very low strength. You need to use portland cement. You can and should use fly ash in your recipe (your mix design to concrete people). Fly ash is a polozan - the secret of the Roman Empire. That's why a lot of their buildings are still standing hundreds of years later.
Your mix design is critical for a lot of reasons. You need strength, you want low shrinkage, you don't want your concrete to constantly be shedding dust, you don't want the surface to pop loose, and a lot of other things. Get a good mix design before you start! Pay very close attention to water cement ratio! Too much water will ruin your mix. It is best to do a lot of reading about foamed concrete before you begin. You don't want to build a nice looking structure, only to watch it crumble over time.