Friday, 3 August 2018

Define Specific Gravity ,Bulk Specific Gravity,Air Content and Percentage Air Voids-Soil

Specific Gravity(G)

Specific gravity is defined as the ratio of the weight of a given volume of soil solids at a given temperature to the weight of an equal volume of distilled water at that temperature, both weights being taken in air.In other wards, it is the ratio of the unit weight of soil solids (𝛾s) to the unit weighs of water (𝛾w). 
                              Thus, G = 𝛾/ 𝛾w
The Indian Standard specifies 270° C as the standard temperature for reporting the specific gravity 

Mass or Apparent or Bulk Specific Gravity (Gm)

It is the ratio of the bulk unit weight of soil mass (𝛾) to the unit weight of water (𝛾w). 
                                Thus, G𝛾𝛾w

Air Content (ac)

The air content is defined as The ratio of the volume of air voids (Va) to the volume of voids (Vv). 
                             Thus, aVVv

Percentage Air Voids (na) 

The percentage air voids is defined as the ratio of the volume of air voids (Va) to the total volume (V) of the soil mass. It is expressed as percentage.
                             Thus, nVV *100