Concrete filler material
My concrete driveway butts up against my foundation for about 40 feet in the side and rear. Over the years, movement of one or the other or both has resulted in a large separation... Up to 3 or 4 inches in spots. About ten years ago, I hired somebody to fill it when it wasn't as pronounced, and they used a hardening sand compound. That lasted, but now it needs filled again.
Any ideas on how to fill it and with what?