How to remove adhesive from ceiling?
I would venture to say that if you remove that cement, the people in the apartment above you would land in your apartment. Your entire building is probably made of poured concrete and you're seeing the bottom of the upstairs apartment's floor.
The Styrofoam™ sheets you're seeing are for sound and thermal insulation between your apartment and the one above.
I'd suggest that you'll want to cut off the torn Styrofoam to create neat, square edges, replace it, then paint over it.
Also, you say &quot;apartment&quot; - to me, that implies that you're renting. I presume you have permission to do the renovation work? Often landlords don't like it when you start messing with their property without permission...