ACI Method of Mix Design Outline
The most common method used in North America is that established by ACI Recommended Practice 211.1
Any mix design procedure will provide a first approximation of the proportions and must be checked by trial batches
Local characteristics in materials should be considered
The following sequence of steps should be followed:
(1) determine the job parameters – aggregate properties, maximum aggregate size, slump, w/c ratio, admixtures,
(2) calculation of batch weight, and
(3) adjustments to batch weights based on trial mix.
Water/cement ratio (w/c ratio) theory states that for a given combination of materials and as long as workable consistency is obtained, the strength of concrete at a
given age depends on the w/c ratio
The lower the w/c ratio, the higher the concrete strength.
Whereas strength depends on the w/c ratio, economy depends on the percentage of aggregate present that would still give a workable mix.
The aim of the designer should always be to get concrete mixtures of optimum strength at minimum cement content and acceptable workability.[gview file=”http://www.ce.memphis.edu/1112/notes/project_2/beam/ACI_mix_design.pdf” profile=”14″]