ACI concrete mix design method
ACI recommends a relationship between compressive strength and w/c ratio. Water demands for aggregates sizes are summarised in relation to the concrete workability (consistence) required. This leads to an estimate of cement content and aggregate content from an assumed concrete plastic density. The rodded bulk volume for the course aggregate is estimated from tables giving the fineness modulus of the fine aggregate and the coarse aggregate size, hence the split between course and fine aggregate calculated.
The ACI also provide guidance on other forms of concrete. Other simplified methods of mix design include BRE Design of normal concrete mixes, and P Owen´s Basic mix design method.