We use paving slabs to make feeding platforms in the fields - they're 'bedded in' on soft, wet, squishy mud and the pigs are kept off them until they've dried out - this has been working
What doesn't work is letting the pigs on them BEFORE they're totally set, they have great fun digging them up again
I'm guessing, if you're building a block sty you'll be putting in foundations for the walls? (you'd be best to!) You could lay the floor inside using slabs and join it to the run - just make sure it slopes away from the sty.
HTH (not sure if it makes sense lol!)