Particle density and water absorption tests - general

2 Particle density and water absorption tests - general 

Determining the density or the specific gravity of aggregates is important as the value is used in calculations such as composition of aggregate in bituminous mixtures, determination of voids in a bituminous mixture and calculations of weight/volume. 

The ratio of the mass of aggregate to the volume the aggregate occupies in water is designated as density and its units of measurement are g/cm, Mg/m or kg/m. The mass of the volume of aggregates to the mass of an equal volume of water, normally at 25°C, or alternatively 23°C or 20°C, is designated as specific gravity. The value determined is dimensionless. 

In either case, what is taken as volume of the aggregate affects the result. 

In an ideal situation in which the aggregates do not have any internally enclosed or surface micro- or macropores, the measured volume (V) coincides with the absolute volume of aggregate. In this case, the absolute density (p) or the absolute specific gravity of aggregates (G) is determined. 

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