Snowplow cutting edges are very hard steel and are reversible as well. They can also be surfaced hardened by any good welder.
Grant..the problem with trying to push gravel or dirt with a plow is that they don't have down pressure but must be allowed to float with the road surface. Underbody scraper blades do usually have down pressure and are used to break up ice on the road. MotorGraders of course are also D/A or they wouldn't be worth a toot.
