Technical Questions

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How is the water-cementitious material ratio (w/cm) expressed?

Q. How is the water-cementitious material ratio (w/cm) expressed?


A. It is expressed as a ratio of the mass of mixing water to the mass of cementitious material; mixing water does not include water absorbed or batched to be absorbed by the aggregate. Water in admixtures and free moisture on aggregates should be accounted for when failure to do so would have a large effect on the actual w/cm such that the specified properties would not be achieved.


References: ACI 311.6-18; ACI 211.1-91(09)

Topics in Concrete: Concrete FundamentalsMixture ProportioningTesting of Concrete

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