Too much water in the mix creates water reservoirs. Channels lead from the reservoirs to the surface, where a watery laitance forms. A weak surface results, leading to concrete crazing, dusting and scaling, especially if finishing operations work the bleed water back into the surface before it can evaporate. When the water reservoirs and channels dry out, air pockets remain that allow water and deicers to enter. When water in the reservoirs freezes and expands, stresses are induced in the concrete making it less durable.