Made with a water-cementitious materials ratio equal to or less than 0.40, quick-dry concrete should reach required water-vapor emission rates within two to three months under most drying conditions. Normal concretes may take several months longer than that.
However, contractors must be able to place and finish the concrete. To obtain the low water-cement ratio, quick-dry concretes must contain a high-range water reducer that may increase air content, time of set and shrinkage. The concretes may also contain high-reactivity pozzolans that affect the window of finishability. And owners must be assured that quick-dry concrete doesn't create long-term maintenance problems such as excessive drying-shrinkage cracking or curling. Because of these concerns, we recommend that you qualify your concrete by documenting its properties with tests for fresh and hardened concrete, and for water-vapor emission.