This test for Gilsonite is completely matches with the test for bitumen that is described below and its based on the standard ASTM D36.
This test method covers the determination of the softening point of bitumen in the range from 30 to 157°C (86 to 315°F) using the Ring-and-Ball apparatus immersed in distilled water (30 to 80°C), USP glycerin (above 80 to 157°C), or ethylene glycol (30 to 110°C).
The measurement of the Gilsonite softening point is also based on this method.
The softening point is useful in the classification of bitumens, as one element in establishing the uniformity of shipments or sources of supply, and is indicative of the tendency of the material to flow at elevated temperatures encountered in service.
To prevent adhesion of bitumen to the pouring plate
when casting disks, the surface of the brass pouring plate may
be thinly coated just before use with silicone oil or grease, a
mixture of glycerin and dextrin, talc, or china clay.
Sample the material in accordance with Practice D140.
And testing of all asphalt specimens within 6 h and all coal tar
Pitch specimens within 41⁄2 h. Heat the bitumen sample with care, stirring frequently to prevent local overheating, until it has become sufficiently fluid to pour. Stir carefully to Avoid incorporation of air bubbles in the sample.
Heat the two brass rings (but not the pouring plate) to the approximate pouring temperature, and place them on the pouring plate treated with one of the release agents.
More than 240 min shall elapse before completion of the test.
Bitumen cleanly with a slightly heated knife or spatula, so that
Each disk is flush and level with the top of its ring
And up to 157°C (315°F); use Thermometer 16C or 16F. The Starting bath temperature shall be 30 6 1°C (86 6 2°F).
110°C (86 and 230°F); use Thermometer 16C or 16F. The starting bath temperature shall be 5 6 1°C (41 6 2°F).
(176°F) shall be determined in a water bath and all softening
Points above 80°C (176°F) shall be determined in a glycerin bath.
Again using forceps, place a ball from the bottom of theBath in each ball-centering guide.
Heat the bath from below so that the temperature Indicated by the thermometer rises at a uniform rate of 5°C(9°F)/min (.Protect the bath from drafts, using shields If necessary. Do not average the rate of temperature rise over The test period. The maximum permissible variation for any 1-min period after the first 3 min shall be 60.5°C (61.0°F). Reject any test in which the rate of temperature rise does not fall within these limits.
SP (glycerin) = 1.026 583 × SP (ethylene glycol) – 1.334 968°C
SP (water) = 0.974 118 × SP (ethylene glycol)- 1.444 59°C
SP (glycerin) = 1.044 795 × SP (ethylene glycol) – 5.063 574°C
SP (water) = 1.061 111×SP (ethylene glycol) – 8.413 488°C