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: |