Make sure the aggregate sizes don't segregate during storage.
Materials for Precasting There are two ways to get concrete for your precasting operation-have ready-mixed concrete delivered or make your own concrete in your shop.
In general, most decorative precasters make their own concrete.
That allows them to make only as much as they need and to more carefully control the characteristics and quality.
Wet-Cast versus Dry-Cast Most decorative precasters use a wet-casting method, as opposed to dry-cast.
Wet-cast means that the concrete has a water-cement ratio of about 0.4 or higher.
Dry-cast concrete is very dry (w/c of 0.30 to 0.36), has zero slump, and the forms can be stripped as soon as the concrete has been consolidated.
Dry-casting requires an expensive dry-casting machine and is typically used for mass production of products like concrete pipe or manholes and also in concrete block production.
But if even you are only making small batches, you will need to maintain stock piles of the various ingredients, which include aggregate-in various sizes, cement and other cementitious materials, admixtures, and reinforcement.
Controlling the quality of the materials is critical, both before they arrive and after.