ASTM D36 for softening point of bitumen (Ring-and-Ball apparatus)
ASTM D36 standard test method for softening point of bitumen (Ring-and-Ball apparatus)
7. Sampling
7.1 Sample the material in accordance with Practice D140.
8. Test Specimens
8.1 Do not start unless it is planned to complete preparation and testing of all asphalt specimens within 6 h and all coal-tar pitch specimens within 4 1/2 h. Heat the bitumen sample with care, stirring frequently to prevent local overheating, until it has become sufficiently fluid to pour (Note 6). Stir carefully to avoid incorporation of air bubbles in the sample.
NOTE 6 - An electric hot plate having a minimum power to unit-surface-area ratio of 37 kW/m2 has been found satisfactory for this purpose.
8.1.1 Take no more than 2 h to heat an asphalt sample to its pouring temperature; in no case shall this be more than 110°C (200°F) above the expected softening point of the asphalt.
8.1.2 Take no more than 30 min to heat a coal-tar pitch sample to its pouring temperature; in no case shall this be more than 55°C (100°F) above the expected softening point of the coal-tar-pitch.
8.1.3 If the test must be repeated later, do not reheat this sample; use a fresh sample in a clean container to prepare new test specimens.
8.2 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.
8.3 Pour a slight excess of the heated bitumen into each ring, and then allow the specimens to cool in ambient air for at least 30 min. For materials that are soft at room temperature, cool the specimens for at least 30 min at an air temperature at least 10°C (18°F) below the expected softening point. From the time the specimen disks are poured, no more than 240 min shall elapse before completion of the test.
8.4 When the specimens have cooled, cut away the excess bitumen cleanly with a slightly heated knife or spatula, so that each disk is flush and level with the top of its ring.
