I pulled up the old glued down parquet at my house recently and at the edge of the slab there is an exposed gap filled with fiberglass insulation, probably about an inch thick, six inches tall. The mastic was just slathered over it to to level the floor in that area. The insulation got damaged when I pried up the mastic, so I'd like to remove it. What would be the best material to replace the fiberglass with, foam board? Also, can I put concrete patch on top to level the floor?

I dont remember coming across insulation in that location. I would sure be interested in the purpose. Was someone just grabbing something to fill a void that wasn't suppose to be there ? An expansion joint an inch wide ???

It's around the whole perimeter of the foundation. I found this website, which sort of helps me. I'm in a moderate climate.

scroll down to the part titled "Insulation Slab Techniques"
http://www.house-energy.com/Insulation/ ... lation.htm

I would not remove it, could be a can o worms. Patch over it

That's interesting. I didnt realize the potential energy loss at that location.
I wouldnt pull out what's left of the insulation either. What I might think about is renewing the missing insulation to keep the concept intact. Maybe stuffing some more high R rated insulation in in the void , then patching over it.
I think if you tried to remove it all and then tried to stuff foam board in there, it would open a can of worms, and not be a tight seal.