[ledhedsymbols]

I don't think there is enough existing slab to tie into. If it was thicker I would suggest using rebar dowels and Hilti epoxy or something like that. With only 2 1/2" to work with, I don't think there is a good way to tie it to existing. Maybe undermine the current slab after you saw-cut out the waste material and then pour so that it locks into the existing slab? Throw a stinger in it while you are pouring to get rid of the voids. Just a cocktail napkin kind of idea.