Concrete strength gain versus time for concrete exposed to outdoor conditions. Concrete continues to gain strength for many years when moisture is provided by rainfall and other environmental sources.























During the first week to 10 days of curing it is important that the concrete not be permitted to freeze or dry out.

In practical terms, about 90% of its strength is gained in the first 28 days.

Concrete compressive strength depends upon many factors:
* Quality and proportions of the ingredients.
* The curing environment.