Although concrete needs about a month to fully cure, it usually is ready to use in a short duration. Due to variations in the weather, concrete mix, placement, and finishing methods, each project will change significantly. After between 24 and 48 hours, your concrete should be sturdy enough to walk on without leaving any traces. Your concrete should have reached at least 70% of its full strength after seven days of curing. It should be safe to drive over, but you might want to wait before rolling large pieces of machinery over it. You can treat your concrete as fully hardened after 28 days.