I need to pour a 7'X10' (6"deep) concrete slab over an existing asphalt surface. I would rather not break up the asphalt, but pour on top of it. Is it ok to secure the slab in place prior to pouring by drilling and inserting 4" vertical re-bar spikes into the asphalt and then pouring over the 4" wire mesh and vertical re-bar spikes? Any suggestions greatly appreciated

If the asphalt is in good condition yes. Use the vertical rebar but see if you can get fiber concrete where you live. I have used it a lot and have had good results,i done one slab with it over 10 years ago and the slab is like it was then if you want use the wire mesh also. Talk to a good concrete contractor in your area first.