It's not the strength of the concrete that matters. It's what is under it that really makes the difference. A highly compacted sub grade is what determines the viability of concrete. If your sub grade is weak, then the concrete will fail. 2400, 3000, 4000 it does not matter. Compact, compact, then compact some more.
If in doubt, have a soils engineer make the final call.
In my project, I have 2400 PSI 6" over native. Highly compacted. I have RV's running through here all day long. No failures at all, and I have 180,000 sq ft of it. Will it crack at some point? Yes. Nothing you can do about that. That is the nature of concrete. Mostly hairline cracks.