A crystalline grout can be used at the cold joint. But if you have a dimpled membrane or similar waterproofing system on the exterior, and there are no special conditions or evidence of water seepage, it's likely overkill.

Here is a link that might be useful: Crystalline Grout

You can also use a self leveling polyurethane caulk. You would need to stuff a foam backer rod into the gap first, since the caulk is runny enough that it will just flow down to the bottom otherwise

Alex

I think he may be talking about the rim joist area. Chpwaman, do you mean the space above the wall (all around the perimeter of the basement)? If so, any/all air gaps first get sealed with caulk or foam, then add insulation.

Getting a professional to spray foam up there is a good way to go. Sometimes folks put fiberglass insulation there, but I've heard that fiberglass can retain moisture (not a good thing for that area), so foam is better. (I used solid foam pieces for our basement, cut to fit, then sealed edges with spray foam - trouble with that is that you have to hold those spray cans upside-down, and it's very difficult in that area (no room to maneuver the cans).

No...I was asking about the cold joint as worthy called it...the area where the basement floor and basement walls meet. There is a small gap all the way around the basement.