I have a concrete 10'x10' concrete slab. I am building a deck 28'x18'. I would like to use the concrete slab as a support for the 10'x10' secion and use dek blocks in the rest of the areas as support. I will be using 4x4's pressure treated screwed to the support beam to level the support beams in the areas sitting on the concrete slab. My question is do I need to attach the 4'x4' support to the concrete slab using concrete screws? The reason why i ask this question is the 4'x' supports sitting on top of the dek blocks are not secured so my thinking is i do not need to attach the supports to the concrete slab. Am i correct?

From you description I am a little confused. It sounds like you would like to use a beam. Using a beam is not an approved method of use for the blocks. It could result in sinking, wobbling, or deck failure. Rather than screwing the posts to the cement would it be possible to use blocks instead.

Deckman

The space between the patio door and concrete slab is not adequate for me to put the dek blocks. I wanted to use the support beams that run from the dek dlocks outside the concrete patio area over the concrete area without the dek blocks on the patio. I need a way to secure the support beams over the concrete patio.

sorry not a beam but the support board (2x6)