Can salt be used to create a slip resistance surface in concrete?
I don't think you'd want to use salt for a couple of reasons:


if you have any rebar in there, salt will increase corrosion
salt will affect the concrete mix, possibly badly affecting strength


Instead, use one of the polymer grip additives designed for this purpose - they can be very cheap, and some are transparent so do not affect the appearance of the concrete.

An example - I haven't used this one, but there are many available.