Is there a risk of frozen water pipes in a home built on a concrete slab. I live in central Indiana

Yes, there is always a risk but many homes are built this way and never have a problem. The water lines in the slab should never get anywhere near freezing if the home is heated and occcupied. The slab is probably 65-70 degrees and the dirt below it rarely gets below 55 degrees. Pipes in an outside wall have a much better chance of freezing.