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.
You can walk it in 2 hours and set heavy objects in 4 hours. Conventional concrete setting times are bit more subjective. Assuming that optimum temperatures are present during pouring and setting, you can *possibly* walk it in 24 hours, but gently. I like to wait 48 hours to be on the safe side. It will take 7 days to reach 2,500 lbs.