This compression system is a very handy invention, especially for Web users, because it lets you reduce the overall number of bits and bytes in a file so it can be transmitted faster over slower Internet connections, or take up less space on a disk.
Concrete hardens to 600PSI (Minimum) after 24 hours. This means that 5 three grown men could all stand on a pogo stick (if that were possible) who's base covers 1 square inch without harming the concrete. You walking with shoes on exert about 10 PSI, well below anything that could damage the new pour.
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.