ABSTRACT
ART. 2.1. WEIGHT O t h e r things being equal, concretes made from aggregates of the same density and grading vary in weight according to the proportion of cement in the mix. With aggregates of normal density, contrary to popular belief, concretes rich in cement weigh less than concretes of weaker mixes, provided always there is enough cement in the mix to fill the voids. This follows from the fact that cement weighs less than concrete. In Fig. 2.1 the
weights are shown of various concretes each made from the same dense-ballast aggregate but with different percentages of cement. One of the curves is for concrete cured in air: the other is for concrete cured by submersion in water. The cement percentages of the nominal mixes given in C.P. 114 (1957) are indicated. It will be seen from Fig. 2.1 that over normal ranges, concrete cured dry weighs about 2 lb/cu. ft. less than concrete cured wet.
