Note that ACI 211.1, Standard Practice
for Selecting Proportions for Normal, Heavyweight, and Mass
Concrete uses “oven-dry relative density (specific gravity)”
(i.e., Gsb) of coarse and fine aggregates in the method for
determining concrete mix designs. Also note that all specific
gravity values used in ACI standards are reported to the
hundredths place (e.g., 2.68)..