The goal of any mix design is to produce a concrete that will meet performance requirements for the specified conditions and use. "Standard Practice for Selecting Proportions for Normal, Heavyweight, and Mass Concrete" is the most widely used guide for concrete mix design. The major steps involved in this method are as follows:
- Choose the slump range and nominal maximum size of coarse aggregate for the type of construction and placing conditions.
- Use tables to approximate the mixing water and air content requirements for different slumps, aggregate maximum sizes, and exposure conditions.
- Select the water-cement or water-cementitious material ratio to meet strength and durability requirements.
- Calculate the amount of cementitious material needed per unit volume of concrete by dividing the weight of mixing water required by the water-cementious ratio. Use the table in ACI 211.1 to estimate the dry-rodded volume of coarse aggregate needed to produce satisfactory workability for normal conditions.
- Sum the solid volumes of water-cementitious materials, air, and coarse aggregate and subtract them from the unit volume to calculate the solid volume of fine aggregate needed.