Reply #2: You can rent a jackhammer pretty cheaply

[Jersey Devil]

I rented one to bust up steps and concrete walks this summer at Home Depot (probably also at Lowes). I think it was something like $70 for the day and it made my 18 year old son so happy that he could do something destructive that I approved of. BTW, 3" is a pretty thin slab and the jackhammer should have no problem with it. If you do it be sure to get a cheap pair of ear protectors, wear safety goggles (a lot of chips) and heavy gloves to protect from the vibrations. It also helps to have a 6'3" healthy 18 year old kid with nothing to do, which you probably can rent if you don't have one of your own. Kids love to destroy stuff.

Also, you might consider hiring one of those "cleanout" companies to do it for you and take it all away in one fell swoop. Though I busted it up myself I had to pay $300 for someone to haul the concrete away.