All precast concrete producers can now use a group of materials called "fly ash" to improve the quality and durability of their products. Fly ash improves concrete's workability, pumpability, cohesiveness, finish, ultimate strength, and durability as well as solved many problems experienced with concrete today–and all for less cost. Fly ash, however, must be used with care. Without adequate knowledge of its use and taking proper precautions, problems can result in mixing, setting time, strength development, and durability.