The short version
- Curing period: the American Concrete Institute’s guidance (ACI 308R) sets a basic curing period of 7 days when it is above 50°F. Curing means keeping the concrete damp: plastic sheeting, wet burlap or a curing compound.
- Design strength: mix strengths like 4,000 psi are measured at 28 days. Quikrete’s data sheet rates its Concrete Mix at 4,000 psi at 28 days.
- Fast-setting mixes: set in 20 to 40 minutes, but still need time to gain strength before heavy loads.
Walking, driving and loading
Follow your contractor’s or the mix maker’s advice for when to walk on or drive on new concrete. Heavier loads wait longer. Cold weather slows curing a lot.
Common mistakes
- Letting the surface dry out on a hot, windy day: it can crack and dust.
- Pouring when frost is coming without protection.
- Adding extra water to make it easier to place, which weakens it.
Sources
- ACI 308R basic curing period (7 days above 50°F), as summarized in US NRC concrete training slides
- Quikrete Concrete Mix (No. 1101) data sheet: bag yields 0.30, 0.375, 0.45 and 0.60 cu ft for 40, 50, 60 and 80 lb
- Quikrete Fast-Setting Concrete Mix data sheet (sets in 20 to 40 minutes)
Sources last checked 1 November 2026.
