Look up your CC without weapon master. If your CD is higher than the listed number, then axe/mace is better, otherwise sword is better. For example if you have 30 CC without weapon master, then you're better off with a sword if your CD is less than 273, otherwise you're better off with an axe/mace. As you can see, by the time you get to 50CC, sword is almost always going to be better.
Note that this is for damage only. For procs on certain barb skills, the higher CC might be better regardless of damage. OTOH, there are many barb skills such as OP Killing Spree or HotA where your in game CC is significantly better than your listed CC and sword becomes an even better option.