How do you Determine the Specific gravity of cement?

Answer 1

Cement is usually purchased as a powdery substance that is mixed with sand, aggregate, gravel and water to form concrete. Since the cement itself is usually a powder, it is hard to measure a standard value for it's specific gravity. And since cement is usually not used by itself, knowing it's specific gravity is not particularly useful.

A more useful question is "What is the typical density of concrete?" A rule of thumb answer is that normal cured concrete has a density of about 150 pounds per cubic foot. This includes the weight of the cement, sand, aggregate, and that part of the water that chemcially binds with the cement to form the concrete. Since water weighs about 62.4 pounds per cubic feet, concrete is about 2.4 times as heavy. Thus the specific gravity of concrete is about 2.4. If you took cement and mixed it with water, you would eventually have a hard lump of useless cement and it would also have a specific gravity of between 2 and 2.4.

Ash Grove Cement from the Foreman, AR Facility normally has a specific gravity of 3.15. Depending on the source of the cement, the specific gravity may vary, but typically it will be close to this figure. Knowing the specific gravity of cement is critical when developing a mix design for concrete, because if one does not know the specific gravities of the raw materials, it is not possible to figure the proportions needed to give you the appropriate yield for a cubic yard of concrete.

Answer 2

To determine the specific gravity of cement, you typically use a Le Chatelier flask method. This involves measuring the weight of a specific volume of cement and comparing it to the weight of an equal volume of water. The specific gravity is then calculated as the ratio of the weight of cement to the weight of an equal volume of water.