To determine the specific gravity of soil solids by Density bottle method.
Specific gravity G is defined as the ratio of the weight of an equal volume of distilled water at that temperature, both weights taken in air.
IS 2720 (Part III) – 1980 is the standard recommended to determine specific gravity of fine grained soils. The value ranges are same as the previous experiment. The average of the values obtained shall be taken as the specific gravity of the soil particles and shall be reported to the nearest 0.01 precision. If the two results differ by more than 0.03 the tests shall berepeated.
Specific gravity of soil solids is defined as the weight of soil solids to weight of equal volume of water.
Equation for specific gravity, G:
G= (W2-W1)/((W2-W1)-(W3-W4))
Where,
W1= weight of empty bottle
W2= weight of bottle + dry soil
W3= weight of bottle + soil + water
W4= weight of bottle + water
Note: This method is normally used for fine-grained soils. The method may also be used for medium and coarse grained soils, if the coarse particles are grained to pass 4.75-mm IS sieve beforeusing