Fracture does almost exactly the same amount of damage as one Butcher's Block. That means it's the same amount of damage as our highest damage ability (excluding Inner Beast). If you look at the rotation below you can see how I play over a time period of 30 seconds (not including buffs and situational usage of other Global Cooldown skills).
You won't put up Fracture right away and the reason I start with Butcher's Block combo is because you always want to get enmity up quickly. This works out as long as you don't have any other tank-class NUKING the boss/mob (which they shouldn't if you're the main-tank).

The rotation is just rince and repeat, after putting fracture up it will cover the whole 30 second period (even the first 15).