The only time I have seen concrete not crack was when the concrete contractor really knew what he was doing. There were water reducing admixtures added (not just a hob nob addition but a careful designed mix) and, this I believe was the real reason it worked, a controlled cure cycle using misters and a protected environment. I believe after this concrete can be placed with no cracks, just is it worth the money for what is really a non-structural issue. Epoxy the cracks that don't follow the saw cuts and have the painters come in. The slab I saw being placed was for a mill and would have machinery placed on it. The slab was a continuous pour and even varied in depth from 6" to 12". No rebar all fiber for reinforcing