The most common method used in North America is that
established by ACI Recommended Practice 211.1
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
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,
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
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.
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.
mixtures of optimum strength at minimum cement content
and acceptable workability.
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