As you can see, there are lots of variables to answering the how long is hamburger meat good for question. Raw hamburger meat (ground beef) is much more perishable than other cuts of beef and will keep in the refrigerator for only 1 to 2 days. Cooked hamburger meat will keep 3 to 4 days in the refrigerator.
Re: Poured side walk/steps, how long to leave forms? I strip the forms 24 hours later, but am careful not to damage the new concrete. It will still be very soft and with crumble if you put too much force on the edges. Usually concrete will harden withing 30 days to the point where it is considered cured.
The main character has been walking every day for 10 years without ever seeing another person. The buckling concrete walk is foreshadowing the fact that the nature will soon overtake the society, since no one uses or upkeeps these things. This can also be seen in the quote, He stumbled over a particularly uneven section of sidewalk. The cement was vanishing under flowers and grass..