Copper pipe and cement - proper installation for repair?

Hello,

I'm doing a bathroom renovation and found some fist-sized divots in the concrete slab once the old vinyl floor was removed and the trim off. Two of those divots are near pipes - one's a copper hot water heater pipe for a baseboard heater, and one is a larger (presumably) sewer pipe.

The sewer pipe is "in the wall" and I'm tempted to leave it alone and not try to fill it. The copper pipe has some paper around it (insulation?). The paper is down to the concrete, but I'm thinking that I need to use some insulation if I want to patch the hole? What's best to put around the copper pipe here? Obviously, I can't remove the existing heater or pipe to add plastic. Is foam insulation sufficient, then fill the hole with patching cement?

The hole is essentially in the corner of the room, so I can't lay tile until I solve this. The house was built in the late 60s.

Thanks!

You can put just about anything around the copper pipe, the whole idea is to keep it from touching concrete; concrete will eat thru copper. Plactic, iron or steel drains can be run with the concrete touching them.

pipe

Wrap tape around it.

What about if there's a green patina on the pipe already? Do I need to clean or gently sand the pipe before wrapping it to get rid of any existing oxidation?

Sorry - I've gotten a few different answers on this, and I just don't want to fill a hole with concrete if I'm not confident I've done it right. The resident plumbing expert at Lowes told me to simply use Great Stuff in the hole and call it a day, and my plumber just said to wrap the pipe and just to buff it before filling with concrete if I really felt it was necessary. Copper.org pretty much says that the only thing you're protecting against is thermal expansion, not corrosion, so contact with concrete wouldn't be an issue - just to leave some extra space.

http://www.copper.org/consumers/copperhome/faq_page_2.html

Also, does anyone know how hot baseboard heat pipes get (180 to 200 degrees)? Some of the insulation I got for wrap had a max temperature threshold.

THANKS!