By Bennett's Concrete and Excavation, Norwich, NY. Updated October 2026.
The short answer
Fresh concrete sets within hours of the pour and is usually firm enough to walk on the next day. The curing period, when you keep it moist and warm on purpose, is typically 3 to 7 days according to the National Ready Mixed Concrete Association (NRMCA). Strength is measured at 28 days, which is the industry standard for rating concrete.
Concrete does not stop at 28 days. Most of the strength comes in the first few weeks, and it keeps gaining slowly after that as long as there is moisture in the slab.
Setting, curing and drying are three different things
- Setting is the change from a plastic mix to a solid. It happens in hours and is what the finishing crew is racing against.
- Curing is keeping water in the concrete and the temperature favorable so the cement keeps reacting. This is what builds strength.
- Drying is water leaving the slab. It matters if you plan to glue down flooring or paint a floor, and it takes much longer than curing.
People often say a slab is 'cured' when they mean it's dry or hard. The three run on different clocks.
A rough timeline
Here's what the numbers look like for a common bagged mix, using the published data for Quikrete Concrete Mix (No. 1101). Ready-mix concrete is ordered to a strength that fits the job, but the shape of the curve is similar.
| Age | What's happening |
|---|---|
| First hours | Concrete sets. Finishing, edging and jointing happen now. |
| Days 1 to 7 | Active curing period. NRMCA says typically 3 to 7 days. |
| 7 days | About 2,500 psi for Quikrete No. 1101 |
| 28 days | About 4,000 psi for the same mix, its rated strength |
See concrete strength and psi explained for what those numbers mean.
Why curing matters
Concrete that dries out too soon stops gaining strength at the surface. NRMCA's curing guide says concrete in a dry environment can lose as much as 50 percent of its potential strength compared with moist-cured concrete. The surface is what takes tires, salt and freeze-thaw, so a poorly cured top layer is the first thing to scale or dust.
Good curing also cuts down on surface cracking, because the top of the slab doesn't shrink faster than the rest.
How concrete gets cured
NRMCA lists two families of methods. Both start right after finishing.
- Keep water on it: fogging or sprinkling, wet burlap kept wet, or ponding on flat work. NRMCA notes that alternate wetting and drying is not acceptable curing.
- Keep water in it: plastic sheeting at least 4 mils thick, or a liquid membrane curing compound sprayed on once the water sheen is gone. Two coats at right angles give more even coverage.
On most patios, walks and driveways, a sprayed curing compound is the practical choice, because nobody has to remember to wet the slab every few hours.
Temperature changes everything
Cold slows curing. Quikrete's data sheet calls for 5 days of curing at 70 degrees F or higher and 7 days when it's 50 to 70 degrees F. NRMCA says placed concrete should be kept above 50 degrees F during curing and protected from freezing until it reaches at least 500 psi.
Heat speeds early strength but lowers the strength the concrete ends up with. In Central NY that means spring and fall pours need blankets and patience, and July pours need fast finishing and early curing. Our guides on cold weather concrete and hot weather concrete go deeper.
Signs curing was cut short
Poor curing doesn't always show the first week. Watch for these over the first year:
- Crazing: a fine web of surface cracks. NRMCA says the cells are usually no more than about 1-1/2 inches across and the cracks rarely go deeper than 1/8 inch. Fast surface drying and late curing are common causes.
- Dusting: a powdery surface that rubs off on a broom or your shoes.
- Scaling: the top layer flaking off after freeze-thaw and salt. See scaling and spalling.
All three are surface problems, which is exactly the layer curing protects.
What this means for your project
Plan to stay off a new slab for the first day, keep cars off it longer (see when you can drive on new concrete), and don't seal it until it has had time to cure and dry. When we pour a patio or driveway, we'll tell you how it was cured and what to avoid in the first weeks.
