Put pvc on the back and painted. Turned out good
Tile and thin set require good substrate.if concrete is flaking the thin set will fail too. Look for penetrating sealer and stop flaking before tilingmy neighbour had huge amount of scaling on his and tried to repair with thinset, self leveling concrete, etc......nothing seemed to work after so many attempts all summer.
Eventually he conceded and will let me offer my services to apply thinset morter and non slip outdoor tiles over the steps next spring when frost is out of the ground.
plan is to rent a concrete planer to grind down to surface. Local rental places have them here for less than $200/day.Tile and thin set require good substrate.if concrete is flaking the thin set will fail too. Look for penetrating sealer and stop flaking before tiling