Engineers in the US don't need a license to call themselves engineers and I did call myself a student at the end, so I think that tells you what I am.
Plus I have a couple years of field and design experience now which doesn't make me an expert, but I've seen sidewalks get poured and that's certainly not how a "control joint" is created. I could have sworn I said concrete shrinks when it cures.

In regards to concrete shrinking as it cures, I could swear I included that up above. The only thing you don't like about what I said was saying it was an expansion join and not a control joint. Go ahead and look at buckled sidewalks because no expansion joint was put in. Also know as contraction/control joint.

I said I wrote this at 1 AM, forgive me for not being on my A game.