Assuming an ERUV, can one salt or sand an icey walkway or steps for safety on Shabbos? Even yes, are there any restrictions?
This would be permitted.
There are two potential problems with spreading sand or salt on the walk on Shabbos. One would be the melocho of Boneh. In this regard salt poses no problem as it is will dissolve and by it’s nature is only temporary. Sand by it’s nature can remain and therefore there are those who are stringent. One may be lenient if necessary. It’s presence is clearly temporary and undesirable once the ice is no longer there. See Eruvin 104a, Shulchan Aruch 313:10, and Shmiras Shabbos Khilchisa Chapter 25 footnote 49.
The other issue is that of Molid, the Rabbinic prohibition of changing something from a solid state to a liquid state. However, here the melting is not being done by rushing the snow with his hands, rather it is being caused by the spreading of the salt. While we are generally stringent even for this form of Molid, the Rama in 318:16 writes that in a case of need one may be lenient. This case may also be comparable to what the Gemara describes in Shabbos 42a that when there is a danger in the public domain one may violate the prohibition of muktzeh to remove it, see Rama 308:6. Presumably this would be true of the Rabbinic prohibition of Molid as well.