Fresh concrete doesn't dry — it cures. Curing is a chemical reaction (hydration) between cement and water that keeps building strength for weeks, as long as moisture stays in the slab. That distinction is why “how long until it's dry” has a longer answer than most people expect.
The short version: you can walk on it in about a day, drive a car on it after a week, and it reaches full design strength at 28 days.
The concrete curing timeline
24–48 hours: forms can usually come off and you can walk on the slab carefully. The surface is set but still green — keep heavy loads off it.
7 days: concrete reaches roughly 70% of its design strength. Passenger vehicles can use a driveway at this point. Most contractors keep it damp through this window.
28 days: concrete is considered fully cured at 100% of its rated strength. It keeps gaining a little strength for years, but 28 days is the engineering benchmark.
Why keeping it wet matters
Hydration needs water. If a slab dries out too fast — hot sun, wind, low humidity — the reaction stalls and you get a weaker, more crack-prone surface. That's why crews mist slabs, cover them with plastic or wet burlap, or spray a curing compound for the first several days. Slower, wetter curing makes stronger concrete.
What changes the timeline
Temperature is the big lever: curing slows sharply below 50°F and can stall near freezing, while hot weather speeds the set but risks cracking. Mix design matters too — high-early-strength and accelerated mixes hit milestones faster. Thicker pours and high humidity both extend the schedule.
Common questions
How long before you can walk on concrete?
Usually 24 to 48 hours for foot traffic, though it depends on the mix and temperature. Stay off it entirely for the first day.
Is concrete cured in 24 hours?
No. It's set enough to walk on, but it's only a fraction of its final strength. Full cure takes 28 days; 70% strength takes about 7 days.
Can it rain on concrete after pouring?
Light rain a few hours after finishing usually won't hurt a slab that has set — moisture actually helps curing. Heavy rain on a still-soft surface can wash out the finish.