The density of cement can be anywhere from 62 to 81 pounds per cubic foot, depending on the type of cement. General purpose cement, for example, can have a density up to 81 pounds per cubic foot.
There is another type of cement called builder's cement, which can have a density of anywhere from 62 to 78 pounds per cubic foot. Bulk density is not important for cement because, when thrown in water, the liquid fills in the spaces in between the particles where the air would normally be.
General purpose cement and builder's cement have different relative density ranges because they are fundamentally different kinds of cement. General purpose cement, also sometimes referred to as GP cement, is considered straight cement, made from cement clinker, gypsum and limestone. This type of cement is used in many different settings for construction of buildings and various other structures. Builder's cement, which is also sometimes referred to as general purpose blended cement, is different from regular general purpose cement because it contains a nominal mass of fly ash. This type of cement is known to maintain its strength for a longer period of time with improved workability and a lower carbon footprint.