jike....typical for wet cure is 7 to 14 days. If you want to achieve 3000 psi in 5 days, I would continue to wet cure as with conventional concrete strength. One reason for wet curing is to mitigate early drying shrinkage and the ensuing cracks. There's enough water in the concrete to hydrate, but the wet curing will provide more uniform curing, top to bottom, and help mitigate curling, crazing, and excessive drying shrinkage.