Using fixed weights of variable ingredients under variable conditions yields a predictable result - a variable product. To avoid problems caused by keeping ingredient weights constant, concrete should be produced to meet performance requirements in accordance with a design formula for the composite mixture. This can be done by applying computer technology. A software system scheduled for release in 1991 allows the producer to store a mixture design formula instead of batch weights in the plant control computer. The mixture design formula is supported by ingredient properties, construction needs, concrete mix performance history, and weather conditions and delivery times. Changes in information within these databases would trigger a mix proportion change.