Originally Posted by SuperJETT
Are you talking about using the cement dry or mixing with water?
Sorry, I forgot to mention water. Yes, you add water, and I believe some hydrated lime. It's been quite some time since I made this mixture so I don't remember the exact ratios.
Well, I guess what you're looking for is thermal mass more so than insulating properties. Like lining the walls with firebricks. That would definitely hold and keep temps stable once the thermal mass reaches ideal temp.