AASHTO T 331:13(2017) Standard Method of Test for Bulk Specific Gravity (Gmb) and Density of Compacted Asphalt Mixtures Using Automatic Vacuum Sealing Method.
Test specimens may be either laboratory-compacted asphalt mixtures or sampled from asphalt pavements. The mixtures may be surface or wearing course, binder or leveling course, or hot mix base.
4.2. Size ofSpecirneiis—Specimens shall conform to the requirements of T 166.
4.3. Specimens shall be taken from pavements with a core drill, diamond or carborundum saw, or by other suitable means.
4.4. Care shall be taken to avoid distortion, bending, or cracking of specimens during and after the removal from the pavement or mold. Specimens shall be stored in a safe, cool place.
4.5. Specimens shall be free from foreign materials such as seal coat, tack coat, foundation material, soil, paper, or foil.
4.6. If desired, specimens may be separated from other pavement layers by sawing or other suitable means. Care should be exercised to ensure sawing does not damage specimens. Jagged edges or sharp aggregates may puncture the plastic bag. Specimen ends or planar edges may require sawing if the bag does not conform to the specimen in a uniform manner.
Bag cutter—A knife, scissors, or other types of clipping devices may be used to quickly open bags.
5.2. Oven—The oven shall be capable of maintaining the appropriate temperature for drying specimens to a constant mass.
5.3. Weighing Device—The weighing device shall have sufficient capacity, be readable to 0.1 percent of the sample mass or better, and conform to the requirements of M 231. The weighing device shall be equipped with a suitable suspension apparatus and holder to determine the mass of the specimen while suspended from the center of the scale pan of the weighing device.
5.4. Plastic Bags— -The two most commonly used sizes of bags are designated as small and large size bags. The small bags shall have a minimum opening of 235 mm (9.25 in.) and a maximum opening of 260 mm (10.25 in.) with a mass of less than 35 g. The large bags shall have a minimum opening of 375 mm (14.75 in.) and a maximum opening of 394 mm (15.5 in.) with a mass of 35 g or more. The bags shall be made of a plastic material that will not adhere to asphalt film and shall be puncture-resistant, capable of withstanding sample temperatures of up to 70°C (158°F), impermeable to water, and contain no air channels for evacuation of air from the bag. The bags shall have a minimum thickness of 0.100mm (0.004 in.) and a maximum thickness of 0.152 mm (0.006 in.). The manufacturer shall provide the bag correction factor (apparent specific gravity) of the bags (usually located in the operator’s manual). Sec the manufacturer’s recommendations to ensure proper handling of bags.AASHTO T 331 pdf download.