Moist Curing

Click to see the Moist Curing chart

During hot weather, it is crucial to moist cure (ensure zero moisture loss) for as long as practical. Since formwork typically helps prevent moisture loss, you should plan to leave the forms on for as long as possible during hot weather. Once products are removed from forms, moist curing is essential during hot weather, as shown on this chart, taken from the 13th edition of the PCA text “Design and Control of Concrete Mixtures.” It shows that the strength gain of concrete is proportional to the moist-cure time. While it is ideal to moist cure for 28 days, this chart shows that you can obtain design strengths after 180 days if moist curing is sustained for seven days. If moist curing is sustained for three days, you can expect to achieve only approximately 80 percent of the mix design strength.