How to fill and finish joints on ceiling between pre-cast concrete planks
There is nothing you can use to fill in the area if yours is like the picture from the site.  Well you can and it could quite possibly look great for a period of time but it will invariable crack in every joint.  Not only due to expansion and contraction but also to movement in the concrete.  

You would have to install wood/metal furring strips across the whole ceiling to do this right.  This would be a bit of work since you would need to secure these to concrete.  And then just sink your drywall into the furring strips.  Given that you have the ability to make holes in the ceiling (you are permitted to) this is a rather "cheap" task for a DIYer but very very labor intensive task.