AASHTO T 295:13(2017) Standard Method of Test for Specific Gravity or API Gravity of Liquid Asphalts by Hydrometer Method.
6.2. Other hydrometers conforming to the performance and accuracy requirements of ASTM E 100 may be used.
6.3. Thermometric Device—accurate to 0. 1°C (0.2°F). An ASTM I 2C thermometer as defined in ASTM E I is suitable. Any other thermometric device of equal accuracy may be used.
6.4. Hvdroineter Cylinder—clear glass, plastic (Note 2), or metal. For convenience in pouring, the cylinder may have a lip on the rim. The inside diameter of the cylinder shall be at least 20 mm (3/4 in.) greater than the outside diameter of the hydrometer used in it. The height of the cylinder shall be such that the hydrometer floats in the sample with at least 25 mm (I in.) clearance between the bottom of the hydrometer and the bottom of the cylinder.
Note 2—Hydrometer cylinders constructed of plastic materials shall be resistant to discoloration by oil samples and must not become opaque by prolonged exposure to sunlight or oil samples.
6.5. Constant-Temperature Bat/i- capable of maintaining the testing temperature within ±0.5°C (1.0°F) and of such dimensions that the level of the liquid is approximately the same as that of the sample in the hydrometer cylinder.
6.5.1. Thermometric Device—a thermometer or electronic temperature-measuring device accurate to
0.25°C (0.5°F) shall be used to measure the temperature of the constant-temperature bath.
6.6. Oven—for preheating the sample, and capable of maintaining the selected testing temperature within ±3°C (5°F).
6.6.1. Thermometric Device— a thermometer or electronic temperature measuring device accurate to 1°C (2°F) shall be used to measure the temperature of the oven.
7.1. Materials tested using this procedure may contain volatile and flammable hydrocarbons. Heat the sample in a covered container to minimize the loss of volatile components. Perform the test in a well-ventilated area, and avoid breathing any vapors that may be generated. Keep sources of ignition away from materials being tested.
8.1. Take samples in accordance with AASHTO R 66. The sample shall be free of foreign substances.
8.2. Thoroughly mix the sample before removing a representative portion for testing.
9. TEMPERATURE OF TEST
9.1. Because of differences in viscosity between various grades of liquid asphalts, the temperature of the test must be adjusted so that it will provide sufficient fluidity to conduct the test over a reasonable period of time. The recommended testing temperatures for the various grades shown in Table 2 arc based on a viscosity of approximately 200 to 500 cSt.AASHTO T 295 pdf download.