ASTM D2746 Test Method for Staining Tendency of Asphalt (Stain Index)
5. Apparatus
5.1 Rings - Square shouldered brass retaining rings conforming to the dimensions required for use in the ring-and-ball softening point apparatus (see Fig. 1 (a) of Test Method D36).
5.1.1 The inside diameter of the ring to be placed in contact with the filter paper during the test is 16 mm (40
/in.).
NOTE 2 - This test method depends on accurate measurement of diameter and precise alignment of the face and rim of the ring on a flat surface. Therefore, deformed rings must not be used.
5.2 Pouring Plate - A flat, smooth, brass plate approximately 50 by 75 mm (2 by 3 in.).
5.3 Paper - Filter paper of the standard double acid-washed analytical grade.
5.3.1 The filter paper must be of sufficient area to accommodate the number of samples and the known material arranged as described in 7.3.
5.4 Support Plate - A flat, clean, smooth metal plate approximately 1.5 mm (1/16 in.) thick and area at least sufficient to support the size of filter paper being used.
5.5 Oven - A constant temperature oven capable of maintaining the test temperature of 80°C (175°F) within ±1°C (±2°F).
5.6 Thermometer - An ASTM thermometer having a range from -20 to 102°C (-5 to 215°F), and conforming to the requirements for Thermometer S12C (or S12F) as prescribed in Specification E2251. As an alternative, any other thermometric device used shall be at least: (1) of equal accuracy to that of the thermometer specified in Specification E2251, (2) capable of indicating temperature to within 1°C (2°F), and (3) stable to within 1°C (2°F) for the duration of the exposure.
5.7 Measuring Rule - A steel rule graduated in 0.5 mm (64ths of an inch).
5.7.1 Hole Template - A metal or plastic template provided with holes of diameter from 16 to 24 mm (40/64 to 60
/in.) in 0.5-mm (1/64-in.) increments may be used as an alternative to the steel rule to measure the diameter of the stain circle after the test.
6. Sampling
6.1 Sample the material in accordance with Practice D140.
