I have a new concrete back patio. At some point we would like to place a hot tub on it. How long should we wait before doing something like that. The concrete pad is 4" thick, 3000 psi with rebar. How long should we wait to insure it has the time to fully cure before placing that much weight on it or covering an area that size.

Concrete cures for years but I've done concrete work and normally I tell folks allow 24 hrs for walking and 48 hrs for anything heavy such as your tub or in most of my cases autos or trucks. You can wait longer if you care to but 2 days is plenty.

For a hot tub as frank said above 2 days should be OK to drive on at least a week, as for the 3000 psi why? I usually won't pour anything less the 4000 psi sidewalks patios floors or driveways, 3000 psi is footer grade mix.

Frankford A little FYI
Most concrete cures about 60 to 70% in two weeks at 70 Degrees. At this temp it takes a standard 30 days before any

2 days is NOT long enough for trucks... Now if you use curing agents and keep moisture in and above 70 Degree then a shorter time in curing.

21 boat you are correct and I forgot my "," as for the hot tub placement 2 days should be OK "," but to drive on at least one week
When I need to drive on sooner than a week I use 4500 psi with a calcium non chloride I get 3850 psi test cylinder breaks in 3 days...