ASTM D3461 Test Method for Softening Point of Asphalt and Pitch
ASTM D3461 Standard Test Method for Softening Point of Asphalt and Pitch (Mettler Cup-and-Ball Method)
5. Apparatus
5.1 A Mettler dropping point cell6 can be used to determine softening points by this test method. These commercially available instruments consist of a control unit with a digital temperature indicator, matched furnace, sample cartridges, and accessories. The control unit automatically regulates the heating rate of the furnace. The softening point is indicated on the readout, and the heating program stopped, when the sample flow triggers a photocell detector. A general view of the components of the Mettler apparatus is shown in Fig. 1.
5.1.1 Control Unit - This unit shall provide a continuous, linear temperature increase from 25 to 250°C at a rate of 2°C/min. A digital readout shall indicate the temperature to 0.1°C throughout.
5.1.2 Furnace Unit - This unit shall be capable of heating a specimen cup assembly, as described in 5.1.3, at a linear rate of 2 +/- 0.3°C/min. It shall include a sensing system capable of detecting the softening point with a precision of 0.1°C.
5.1.3 Specimen Cup Assembly - A cup of chromium-plated brass, or stainless steel conforming to the requirements for Type 303 (UNS 530300) as prescribed in Specification A 314, with dimensions shown in Fig. 2. It shall be placed in the assembly so that the test specimen will flow down a distance of 19 mm before interrupting a light beam and stopping the heating program as the softening point is reached.
5.1.4 Lead Ball - A lead ball weighing 3.20 +/- 0.10 g. A32-caliber lead shot is suitable for this purpose.
6. Reagents
6.1 Xylene, industrial grade.
