I have a concrete floor and a cast iron toilet flange . One side has broken where the toilet bolt goes on one side. There seems to be a space between the flange and the concrete floor. I really don't want to try and break flange but will if necessary.
Ive seen these repair splicing method and the PVC insert with the rubber flange that expands when you tighten internal screws BUT you have to install screws to secure it to the floor. Having the concrete floor I need a hammer drill.
Can this type of flange be used without sing the screws ?

Where's all our plumbers and builders?

All I can say is that there are countless Youtube videos on various ways to repair a toilet flange in a concrete floor.
I would say as a DIYer who has never done one in concrete 'Of course you break the flange.' You replace it with a PVC insert with a new flange (don't see why you need one that expands?) and fill around the edge with concrete patch. Pad the drain while you work. Make sure everything is very flat and level.

Agree or you can try this Sioux Chief Stainless-Steel Flange Repair Ring-886-MR - The Home Depot (http://www.homedepot.com/p/Sioux-Chief-Stainless-Steel-Flange-Repair-Ring-886-MR/202274075)

There are number of ways to repair broken closet ring. Go with Ballengerb's advice. Quick, clean fix.

Milo

Bareboat should be breathing a huge sigh of relief about right now. You guys just saved him a lot of work.