T0604-2011 Asphalt penetration test

I. Purpose and Scope

1.1 This method is applicable to the determination of penetration of road petroleum asphalt, polymer-modified asphalt, or diluted asphalt and emulsified asphalt residues.

1.2 This method is also applicable to the determination of asphalt penetration under multiple temperature conditions and the calculation of the penetration index PI.

1.3 The penetration measurement range of this method is 0–500 (0.1 mm).

II. Instruments and Materials

2.1 Needle Penetration Tester: To improve testing accuracy, the needle penetration test should be conducted using a needle penetration tester capable of automatic timing. The needle and needle rod must move vertically without significant friction, and the penetration depth should be accurate to 0.1 mm. The mass of the needle and needle rod assembly is 50 g ± 0.05 g, with an additional 50 g ± 0.05 g weight, for a total mass of 100 g ± 0.05 g to meet the load requirements of the test. The instrument should have a platform for placing a flat-bottomed glass dish and a leveling device; the needle rod should be perpendicular to the platform. A brake button for the needle rod should be provided to allow it to fall freely. The needle rod should be easily assembled and disassembled for checking its mass. The instrument also includes a freely rotating and adjustable cantilever arm with a cold light source (such as a small mirror or a spotlight bulb) at its end to observe the contact between the needle tip and the sample surface. When other test conditions are used, this should be noted in the test results.

Customizable features: +Y (Mini Printer); +E (Network Interface); +U (USB Data Export)

2.2 Standard needle: Consists of a needle body and a needle handle.

2.3 Flat-bottomed glass dish: Capacity not less than 1L, depth not less than 80mm. It should have an internal stainless steel tripod to ensure stability. For easy temperature control of the sample during the penetration test, the flat-bottomed glass dish should be connected to a constant temperature water bath to form a circulation system.

2.4Thermometer or temperature sensor: Range 0～50℃, graduation 0.1℃.

2.5Timer: Stopwatch or electronic timer, minimum graduation 0.1s, maximum permissible error ±0.10s/h.

2.6Displacement gauge or displacement sensor: Accuracy 0.1mm.

2.7 Sample dish lid: Flat glass, diameter not less than the opening size of the sample dish.

2.8Solvent: Trichloroethylene, etc.

2.9Others: Electric furnace or sand bath, asbestos mesh, metal basin or crucible, degreased cotton, etc.

Select appropriate sample dishes and standard needles. If the needle penetration is greater than 350 (0.1 mm), then select a loIII. Methods and Proceduresng needle penetration needle.

III. Methods and Procedures

3.1 Calibration of the Needle Insertion Meter and Standard Needle

3.1.1 The needle insertion meter should be calibrated annually to check the quality of each part.

3.1.2 The standard needle should be calibrated annually, and its appearance should be inspected under a microscope. Before each use, a visual inspection should be performed to ensure it is free of rust, has a sharp, burr-free tip, and does not bounce when rolled on a level table.

3.2 Determining Test Conditions

3.2.1 The standard test conditions are: temperature 25℃, load 100g, and penetration time 5s. If other conditions are used, this should be noted in the report.

3.2.2 The penetration index (PI) should be measured at three or more temperatures, such as 15℃, 25℃, and 30℃. If the penetration value at 30℃ is too high, 5℃ can be used instead. For arbitration tests, at least five temperature conditions should be used, and penetration measurements at 10℃ and 20℃ should be added.

3.2.3 Estimate the penetration range of the sample and select a suitable sample dish and standard needle. If the penetration is greater than 350 mm (0.1 mm), a long-penetration needle should be selected.

3.3 Preparation

3.3.1 Prepare the sample according to method T0602. While heating the sample, preheat the sample container and metal spoon in the same oven.

3.3.2 Adjust the constant temperature water bath to the required test temperature and maintain stability.

3.3.3 Pour the sample into the preheated sample dish, ensuring the sample height exceeds the expected penetration value by 10 mm. Cover the sample dish to prevent dust from falling in. The sample dish containing the sample should be cooled at room temperature (23℃±5℃) for at least 1.5 h (small sample dish), 2 h (large sample dish), or 3 h (special sample dish). After cooling, transfer it to a constant temperature water bath that has reached the test temperature ±0.1℃ and continue to maintain the temperature for at least 1.5 h (small sample dish), 2 h (large sample dish), or 2.5 h (special sample dish). Simultaneously, place the standard needle in the constant temperature water bath for maintenance.

Note: Preheating the sample dish can reduce air bubbles. The temperature can be 40-50℃, not exceeding the softening point. If there are air bubbles on the sample surface, they can be removed by briefly flashing a flame over the top of the bubble.

Note: The sample holding time should be adjusted according to the ambient temperature and the test temperature. When the ambient temperature is higher than 30℃ or the test temperature is lower than 25℃, the holding time should be appropriately extended.

3.3.4 Leveling the needle penetration gauge. Inspect the needle rod and guide rail to ensure there is no water or other foreign matter and no obvious scratches. Wipe the standard needle with a solvent such as trichloroethylene, then dry it with clean, dry, degreased cotton. Insert the standard needle into the needle rod and secure it with bolts.

3.4 Test Procedure

3.4.1 Remove the sample dish that has reached constant temperature and immediately place it onto the support of a flat-bottomed glass dish in water at a temperature of ±0.1℃ (water from a constant temperature water bath can be used), ensuring the sample is fully immersed.

3.4.2 Place the flat-bottomed glass dish containing the sample on the platform of the penetration meter. Adjust the cold light source so that the shadow of the standard needle is projected onto the sample surface. Slowly adjust the height of the penetration meter until the needle tip just touches the reflected shadow on the sample surface. Gently pull down the lever to make it contact the needle connecting rod, resetting the displacement gauge or dial pointer to zero.

3.4.3 Remove or turn off the cold light source. Begin the test by pressing the release button. The standard needle will fall and penetrate the sample, starting the timer. The penetration will automatically stop after the specified time (5s).

3.4.4 Gently pull down the lever to make it contact the needle connecting rod, and read the displacement gauge or dial pointer reading, accurate to 0.1mm. 3.4.5 The same specimen shall be subjected to at least three parallel penetration tests. The distance between each test point and the edge of the sample dish shall not be less than 10 mm. If the flat-bottomed glass dish is not connected to the constant temperature water bath for circulating insulation, the flat-bottomed glass dish containing the sample dish shall be placed in the constant temperature water bath after each test to maintain the water temperature in the glass dish at the test temperature.

3.4.6 A clean standard needle should be used after each penetration test. When the penetration is less than 200 mm, the standard needle can be removed, wiped with degreased cotton soaked in solvents such as trichloroethylene, and then dried with clean, dry degreased cotton. When testing asphalt specimens with a penetration greater than 200 mm, at least three standard needles shall be used. After each penetration test, the needle shall be left in the specimen until three parallel tests are completed before removing the standard needle.