Bricks, Masonry, Asphalt and Concrete - Pour Concrete on top of concrete

I have a concrete garage floor. The concrete is sloughing off in places. I am about to install a machine shop with machines that weigh over a ton and do not have nice rubber wheels like a car. I would like to pour a slab on top of this floor. Can anyone PLEASE give me suggestions. How thick should this new slab be? Should I put metal in it as well..

The shop is about 30ft by 30ft.

Jim

if your want your equipment to be supported properly you will need at least 5-in of concrete, I would just tear out the old floor and pour a 4000 psi mix. if you pour on top of your floor you may make all of your doors and other parts of the shop the wrong heighth,
Or you could just lay out where you want your equipment, then cut out the size of concrete where each piece will sit. Then excavate down about 18 in, place gravel into the hole and pack it thouroly in 3-in lifts, about 6 in of gravel then place some rebar in about a 1 foot cross pattern and at about 3 in from the surface pour a 4000 psi mix and set anchors for your equipment

life begins when the kids leave home and the dog dies

I agree with speedwrench. In this case, pouring a thin layer on top of the old is a bad idea. The machines are too heavy and the vibration would most likely crack the new concrete up.
I would either tear out the entire old floor and replace with at least 6 inches of heavily reinforced 4,000 psi concrete, or do as speed suggested and cut out portions of the floor and do the same. The anchors are a good idea too.

I own a machine shop and you don't want anchors in your floor. The machines will be put on leveling pads and leveled with "jacking screws". The sectioning of the concrete isn't a bad idea though. Just make sure the entire machine is on its own slab. It can't be on separate slabs.