Instructions for Using the Asphalt Penetration Tester

　　1. Purpose and Scope of Application
　　1.1 This method is applicable to the determination of the penetration of road petroleum asphalt, polymer-modified asphalt, and the residue remaining after evaporation of liquid petroleum asphalt or emulsified asphalt, using a needle with a diameter of 0.1 mm. The standard test conditions are as follows: temperature 25℃, load 100 g, and penetration time 5 s.
　　1.2. The Penetration Index (PI) is used to characterize the temperature sensitivity of asphalt and is preferably determined at 15℃ and 25℃.
　　The penetration value is determined under two or more temperature conditions, including 30℃, and then calculated according to the prescribed method. If the penetration value at 30℃ is excessively high, 5℃ may be used as a substitute. The equivalent softening point T800 is the temperature corresponding to an asphalt penetration value of 800, and it is used to evaluate the high-temperature stability of asphalt. The equivalent brittle point T1.2 is the temperature corresponding to an asphalt penetration value of 1.2, and it is used to assess the low-temperature crack resistance of asphalt.

　　2. Main testing equipment
　　2.1 Penetrometer: Accuracy class 0.1 mm.
　　2.2. Standard needle: Made of hardened and tempered stainless steel, with a total mass of 2.5 g ± for the needle and needle shaft combined.
　　0.05 g
　　2.3. Sample Dish: Made of metal, cylindrical with a flat bottom. The inner diameter of the small sample dish is 55 mm, and its depth is...
　　35 mm (suitable for samples with a penetration value less than 200); the large sample dish has an inner diameter of 70 mm and a depth of 45 mm (suitable for samples with a penetration value between 200 and 350); for samples with a penetration value greater than 350, a special sample dish must be used, with a depth of at least 60 mm and a volume of at least 125 ml.
　　2.4. Constant-temperature water bath: The capacity shall be no less than 10 L, and the temperature control accuracy shall be 0.1℃. In the water bath...
　　A perforated shelf shall be provided, located no less than 100 mm below the water surface and at least 50 mm above the bottom of the sink.
　　2.5. Flat-bottom glass dish: Capacity not less than 1 L, depth not less than 80 mm. Equipped with a...
　　Stainless steel tripod stand, which ensures stable positioning of the sample dish. 2.6. Thermometer: Range from 0℃ to 50℃ with a resolution of 0.1℃.
　　2.7. Sample Dish Lid: Flat glass with a diameter no smaller than the opening size of the sample dish.
　　2.8. Solvent: Trichloroethylene, etc.
　　2.9. Standard sieve (filter screen): Mesh aperture size 0.6 mm.

　　3. Experiment Preparation
　　3.1. Set the constant-temperature water bath temperature to the experimental temperature and check whether the temperature control accuracy meets the requirements. 3.2. Place the sample container, complete with its lid, into the constant-temperature oven.
　　3.2.1. When the petroleum asphalt sample contains moisture, the oven temperature should be around 80℃.
　　Heat until all the asphalt has solidified for dehydration.
　　3.2.2. When there is no moisture in the petroleum asphalt, the oven temperature should be above the softening point temperature.
　　90℃, typically around 135℃.
　　3.3. When the petroleum asphalt sample contains moisture, place the sample container on temperature-controlled sand.
　　Dehydrate the sample by heating in a water bath, oil bath, or heating mantle. The dehydration time should not exceed 30 minutes, and the sample should be gently stirred with a glass rod to prevent localized overheating. Under the condition that the asphalt temperature does not exceed 100℃, carefully dehydrate the sample until no foam is present. The final heating temperature should not exceed 100℃ above the softening point for petroleum asphalt or 50℃ above the softening point for coal asphalt.
　　3.4. Filter the asphalt from the sample container through a 0.6-mm sieve, and pour it into the mold without allowing it to cool between pours.
　　Place the sample into the mold for the asphalt penetration test. As required, the sample can also be divided and placed into one or more asphalt sample containers that have been thoroughly cleaned and dried. The number of containers should be sufficient to accommodate the asphalt samples needed for the entire batch of test items, with an adequate margin to spare.
　　3.5 During the asphalt molding process, if the temperature drops, it can be appropriately reheated in an oven. Test...
　　After the sample has cooled, the number of times it is reheated should not exceed two, to prevent asphalt aging from affecting the experimental results. To avoid introducing air bubbles, do not repeatedly stir the asphalt when pouring it into the mold. Any asphalt remaining after molding must be cleaned immediately and should never be reused.