ASTM D5 Standard Test Method for Penetration of Bituminous Materials
9. Procedure
9.1 Examine the needle holder and guide to establish the absence of water and other extraneous materials. If the penetration is expected to exceed 350 use a long needle, otherwise use a short needle. Clean a penetration needle with toluene or other suitable solvent, dry with a clean cloth, and insert the needle into the penetrometer. Unless otherwise specified place the 50-g weight above the needle, making the total weight 100 ± 0.1 g.
9.2 If tests are to be made with the penetrometer in the bath, place the sample container directly on the submerged stand of the penetrometer. Keep the sample container completely covered with water in the bath. If the tests are to be made with the penetrometer outside the bath, place the sample container in the transfer dish, cover the container completely with water from the constant temperature bath and place the transfer dish on the stand of the penetrometer.
9.3 Using the level indicator, ensure that the apparatus is level.
9.4 Either note the reading of the penetrometer dial or bring the pointer to zero. Position the needle by slowly lowering it until its tip just makes contact with the surface of the sample. This is accomplished by bringing the actual needle tip into contact with its image reflected on the surface of the sample from a properly placed source of light. Quickly release the needle holder for the specified period of time and adjust the instrument to measure the distance penetrated in tenths of a millimetre. If the container moves, ignore the result.
9.5 Make at least three determinations at points on the surface of the sample not less than 10 mm from the side of the container and not less than 10 mm apart. If the transfer dish is used, return the sample and transfer dish to the constant temperature bath between determinations. Use a clean needle for each determination. If the penetration is greater than 200, use at least three needles leaving them in the sample until the three determinations have been completed. If the sample container is less than 65 mm in diameter and the expected penetration is greater than 200, make one penetration in each of the three separate containers prepared as per section 7.2.
NOTE 6 - With a 55 mm container and a sample with expected penetration greater than 200, it is often not possible to position the needle holder for a third determination without bumping the other two in-place needles. For routine testing it is acceptable to use a single container for all three needle penetrations, moving the first two needles as necessary, provided that the difference between the highest and lowest penetration values does not exceed the value specified in section 10.1.
