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Concrete over asphalt over concrete !

Q. I have an interesting dilemma, perhaps someone could offer guidance on. My driveway, originally constructed in 1948ish, was poured concrete, about 6 inches thick. Apparently, someone along the time line, decided that they did not like concrete, so, they paved over it with asphalt, the resulting thickness now being about 8-9 inches thick. I know the net is littered with questions regarding concreting over asphalt, however, my question is this. Would this arrangement be a satisfactory base for a new thickness of 4-5 inch concrete? I am raising the grade anyway, and the prices I am getting to rip this out combination is completely out of reality. Does anyone have any suggestions?? I cannot believe that somehow I could not use this for some sort of base, but, I am NOT a professional.

A. For residential concrete, it is my opinion that pouring concrete over existing concrete or asphalt is ok, as long there are no major structural problems with the existing slabs. I do recommend having a 2 inch buffer of sand or pea gravel between the old and new. This allows the old and the new slabs to shift or move separately from one another.