AASHTO T 166:16(2020) Standard Method of Test for Bulk Specific Gravity ( Gmb) of Compacted Asphalt Mixtures Using Saturated Surface-Dry Specimens.
4. TEST SPECIMENS
4.1. Test specimens may be either laboratory-compacted asphalt mixtures or sampled from asphalt pavements.
4.2. Size of Specimens—It is recommended that: (1) the diameter of cylindrically compacted or cored specimens, or the length of the sides of sawed specimens. be at least equal to four times the maximum size of the aggregate; and (2) the thickness of specimens be at least one and one-half times the maximum size of the aggregate.
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.
Dry the specimen to a constant mass at a temperature of 52 ± 3°C (125 ± 5°F). Samples saturated with water shall initially be dried overnight and then weighed at 2-h drying intervals. Recently compacted laboratory samples, which have not been exposed to moisture, do not require drying. As an alternative to oven drying to constant mass, drying the sample according to R 79 may be used. When using R 79 to achieve constant mass, perform the drying procedure at least twice, with a mass determination after each drying cycle.
6.2. Cool the specimen to room temperature at 25 ± 5°C (77 ± 9°F), and record the dry mass as A (Note 2). Immerse each specimen in the water bath at 25 ± 1°C (77 ± 1.8°F) for 4 ± 1 mm, and record the immersed mass as C. Remove the specimen from the water bath; damp-dry the specimen by blotting it with a damp towel, and determine the surface-dry mass as B as quickly as possible the entire operation is 1101 to exceed 15 s). Any water that seeps from the specimen during the weighing operation is considered part of the saturated specimen. Each specimen shall be immersed and weighed individually.
Note 2—If desired, the sequence of testing operations may be changed to expedite the test results. For example, first the immersed mass C can be taken, then the surface-dry mass B, and finally the dry mass A.
Note 3—Terry cloth has been found to work well for an absorbent cloth. Damp is considered to be when no water can be wrung from the towel.AASHTO T 166 pdf download.