What is a common method for calculating specific gravity in aggregates?

The method of calculating specific gravity in aggregates by comparing the weight of aggregates in air and water is based on Archimedes' principle. This principle states that the buoyant force acting on an object submerged in a fluid is equal to the weight of the fluid displaced by the object.

To determine the specific gravity, the weight of the aggregate is measured in air, followed by its weight when submerged in water. The specific gravity is then calculated using these weights, where the difference between the two weights allows for the calculation of the volume of water displaced, leading to the specific gravity of the aggregate being derived as a ratio of the weight of the aggregate to the weight of the water displaced.

This method provides accurate results as it compensates for the buoyant effects of water, thus reflecting the true density of the aggregates. It is widely accepted in the field of materials testing for its reliability and adherence to established testing standards.

Other methods mentioned, such as using a graduated cylinder, a pressure sensor, or weighing aggregates before and after drying, do not accurately determine specific gravity based on the fundamental principles related to density and buoyancy, making them less suitable or indirect approaches for this specific measurement.