Running tip - When you see a cement truck ahead, you...
... turn around and run the opposite way...
Or slow down and search for wet cement.
Otherwise, you may do what I did. I was totally "in the zone," "Gateway to 8K" music louder than the horn on a cement truck. And then it happened very fast - there was the cement truck, and I was running through only-5-minutes-ago-laid-down wet cement. Or rather, I was already on solid ground, and my feet were covered in cement up to the ankles.
Honestly, there were no signs. The workers were on the opposite corner so I had nothing to warn me, except the truck. To their defense, the truck driver was what Chicago thought was a tornado siren. And I was the tornado.
Before I knew it, I was appologizing and the workers were hosing my feet down. They were very nice, and quickly fixed the side-walk. I ran (wishing the earth would swallow me whole) home, and put my Adizeros in the wash hoping they wouldn't come out (cement) crisp.
So, don't expect signs, instead watch for the truck. If there's a truck there, wet cement could be anywhere.
Funny, eh?