The % of Cement in Fresh Concrete Asimple test for determining the percentage of cement in fresh concrete is based on a density measurement. Asample of concrete is taken immediately after it has been hatched. The gravel is screened out leaving only the wet cement and sand mixture. This is quickly dried before the hardening reaction can occur. The density of the dry cement and sand mixture is then determined. The sample is weighed, and its volume is determined by the displacement of kerosene. Since the densities of the sand and cement are known, the percentage of cement in the concrete can be calculated assuming that the density of the concrete is a linear combination of the densities of the sand and cement.
Density of Mixture =
368 1 Journal of Chemical Education
of Denslfy o (Fractron Cement ) ( Cement 3
+
Fraction) (Density) ( l - of cement o f sand
