HELP! Slab and Rebar

[layman]

My builder was suppose to chose either 1/2" or 5/8" rebar for the slab, whichever was better. He has had delivered 1/2" rebar and plans to use 3000psi concrete.

Is the smaller 1/2" better, not much difference in light of the 3000psi, or has my builder cut a corner to save money to my slab's detriment? I still have time to make him exchange the 1/2" package for a 5/8" package. Help!

thank you,

House in Progress

[Rich]

#4 rebar is pretty standard for most residential construction. Unless you have a floating slab (used in areas of expansive soils) with large spans #4 should be just fine.