Determination Of Specific Gravity Of Bitumen

 

STANDARD

  • IS: 1202—1978.

DEFINITION

  • Specific gravity is the ratio of the mass of a given volume of the substance to the mass of an equal volume of water.

APPARATUS 

  •  Specific gravity bottle of 50 ml capacity (Ordinary specific gravity bottle for material which remain absolutely fluid at 27 °C and wide mouthed capillary is used for materials which remain semi solid or high viscous at 27 °C)
  • Constant temperature bath having a depth greater than that of Pycnometer capable of being maintained within 0.2 °C of the specified temperature.
  • Balance of capacity 500grams and sensitivity 0.01gm.

PROCEDURE

  • Clean dry and weigh the specific gravity bottle together with the stopper (A).
  • Fill it with freshly boiled and cooled distilled water and insert the stopper firmly.
  • Keep the bottle up to its neck for not less than half an hour in beaker of distilled water at a temperature of 27 ± 0.1°C or any other temperature at which specific gravity is to be determined.
  • Wipe all surplus moisture from the surface with a clean, dry cloth and weigh it (B)
  • Bring the bituminous material to the fluid condition by gentle application of heat, care being taken to prevent loss by evaporation.
  • When the material is sufficiently fluid, pour the bituminous material in to the clean, dry specific gravity bottle to fill at least half.
  • Slightly warm the bottle before filling the material
  • Keep the material away from touching the sides above the final level of bottle and avoid the inclusion of air rubbles.
  • The use of small funnel will prevent contamination of the neck of the bottle.
  • To permit escape of entangled air bubbles, allow the partly filled bottle to stand for half an hour at a suitable temperature, then cool to the specified temperature, and weigh with the stopper (C).
  • Fill the specific gravity bottle containing the asphalt with freshly boiled and cooled distilled water placing the stopper loosely in the specific gravity bottle. 
  • Do not allow any air bubbles to remain in the specific gravity bottle.
  • Place the specific gravity bottle in the water bath and press the stopper firmly in place.
  • Allow the specific gravity bottle to remain in the water bath maintained at a temperature of 27 ± 0.1°C for a period of not less than 30 minutes.
  • Remove the specific gravity bottle from the water bath, wipe all surplus moisture from the surface with a clean dry cloth and weigh it along with the stopper.

CALCULATIONS

  • Specific gravity =   ( (C-A ) /  (B-A)- (D-C) )
    A=  Weight of specific gravity bottle
    B =  Weight of specific gravity bottle filled with distilled water.
    C = Weight of specific gravity bottle about half filled with the bituminous material
    D = Weight of specific gravity bottle about half filled with the material and the rest with distilled water.  

REPORT

  • Express the ratio of mass of a given volume of the bituminous material to the mass of an equal volume of Water.

PRECAUTIONS

  • Only freshly boiled and cooled distilled water shall be used.
  • At no time of weighing shall the temperature of the apparatus be allowed to exceed the specified temperature.

DETERMINATION OF SPECIFIC GRAVITY
IS 1202 -1978

Description Units Test I Test 2 Average
Weight of Specific gravity bottle (A) gms
Weight of Specific gravity bottle + distilled water (B) gms
Weight of Specific gravity bottle-f bitumen( C) gms
Weight of specific gravity bottle+ bitumen +distilled water(D) gms
Specific gravity of bitumen = ( C-A ) / (B-A) – ( D-C )
Remarks:

 

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