OBJECTIVE
This method covers the determination of the specific gravity of semisolid bituminous materials, asphalt cements, and soil tar pitches by use of a pycnometer.
The specific gravity of semisolid bituminous materials, asphalt cements, and soft tar pitches shall be expressed as the ratio of the mass of a given volume of the material at 250 C(770 F) or at 15.6°C (60°F) to that of an equal volume of water at the same temperature, and shall be expressed thus:
Specific gravity, 25/25°C (77/770F) or 15.6/15.6°C (60/60°F)

PROCEDURE
1. Thoroughly clean, dry, and weigh the pycnometer to the nearest 1 mg. Designate this mass as A.
2. Fill the pycnometer with freshly boiled distilled water at test temperature and place the stopper in the pycnometer. Do not allow any air bubbles to remain in the pycnometer.
3. Allow the pycnometer to remain in the water for a period of not less than 30 min. Remove the pycnometer, immediately dry the top of the stopper with one stroke of a dry towel (Note 1), then quickly dry the remaining outside area of the pycnometer and weigh to the nearest 1 mg. Designate the mass of the pycnometer plus water as B.
4. Preparation of Sample Heat the sample with care, stirring to prevent local overheating, until the sample has become sufficiently fluid to pour. In no case should the temperature be raised to more than 560C (100°F) above the expected softening point for tar, or to more than 111°C (200°F) above the expected softening point for asphalt. Do not heat for more than 30 minutes over a flame or hot plate or for more than 2 hours in an oven, and avoid incorporating air bubbles in the sample.
5. Pour enough sample into the clean, dry, warmed pycnometer to fill it about threefourth to its capacity. Take precautions to keep the material from touching the sides of the pycnometer above the final level, and to prevent the inclusion of air bubbles (Note 3). Allow the pycnometer and its contents to cool to ambient temperature for a period of not less than 40 minutes, and weigh with the stopper to the nearest 1 mg. designate the mass of the pycnometer plus sample as C.
6. Fill the pycnometer with freshly boiled distilled water at test temperature and place the stopper in the pycnometer. Do not allow any air bubbles to remain in the pycnometer.
7. Allow the pycnometer to remain in the water bath for a period of not less than 30 minutes. Remove the pycnometer from the bath. Dry and weigh using the same technique as that employed in Procedure No.3. Designate this mass of pycnometer plus sample plus water as D.