The specimen preparation method for bitumen ensures that the bitumen sample is properly treated to maintain its physical properties before quality testing in the laboratory. This method covers the steps of heating, dewatering, and filtration, and is suitable for a wide range of asphalt types, including viscous asphalt, coal pitch, and emulsified asphalt. Through standardized specimen preparation, the accuracy and consistency of test results can be improved, and a reliable basis for subsequent quality evaluation can be provided.
Purpose and Scope of Application
The specimen preparation method for bitumen is designed to provide high-quality bitumen samples for subsequent performance testing. It is suitable for viscous road petroleum asphalt, coal asphalt, polymer modified asphalt, etc., especially for tests that can only be carried out after heating. Depending on the testing needs, the number of samples is usually not less than 600 grams.
Technical requirements for instruments and materials
Oven – 200°C, with temperature control and regulation.
Heating equipment – electric or gas stoves (propane, petroleum gas, natural gas).
Asbestos mat – for placing on heating equipment.
Filter sieve - pore size 0.6mm.
Sample utensils – metal pots or porcelain crucibles.
Beaker – 1000mL capacity.
Thermometer - range 0~100°C and 200°C, graduation value 0.1°C.
Balance - weighing range of 2000g, inductance is not more than 1g; The weighing range of 100g is not more than 0.1g.
Other equipment – glass rods, solvents, cotton yarn, etc.
Methods and Steps:
Hot asphalt specimen preparation
Heat treatment
The asphalt specimen is heated in an oven, and if the sample contains moisture, the oven temperature is set to about 80°C to ensure that the asphalt is completely melted and dehydrated; If there is no moisture, the temperature should be 90°C above the softening point (usually about 135°C).
Asphalt should not be heated directly with an open flame.
Dehydration process
Heat and dehydrate in a temperature-controlled sand bath, Oil Bath or electric heating jacket, if it must be heated by an electric or gas stove, an asbestos mat should be placed, and the heating time should not exceed 30 minutes.
Stir gently to prevent local overheating, and the temperature should not exceed 100°C.
Filtration and molding
The asphalt is filtered through a 0.6 mm sieve and immediately poured into the mould for each test.
If the temperature drops too much, you can heat it properly and then fill the mold.
clean
The remaining asphalt after filling the mold should be cleaned immediately and should not be reused.
Preparation of emulsified bitumen specimens
Mix well
For emulsified asphalt, gently shake the sample container to make the sample even up and down.
sampling
Pour the required amount of emulsified bitumen into a sample container or beaker for testing.
Prepare your own emulsified asphalt
Prepare emulsifier, water and asphalt according to the proportion, weigh the corresponding quality of emulsifier and heat it to 40~60 °C, add water and stir evenly.
Heat the asphalt to 120~150 °C, and then mix the two in an emulsifier to observe the emulsification to ensure the success of emulsification.
conclusion
The specimen preparation method of asphalt ensures the representativeness and reliability of the specimen through standardized operating procedures, which in turn provides a reliable basis for subsequent performance tests. These steps help to improve the detection accuracy of asphalt and the confidence of the results, laying a solid foundation for applications in highway construction and related fields. With the right specimen preparation, the quality and performance of the asphalt in practical applications is ensured.
summary
The method of specimen preparation for bitumen is critical to ensure that the sample remains in excellent condition until it is tested for quality. Through standardized heating, dehydration and filtration steps, changes in sample performance can be effectively avoided and the accuracy of test results can be ensured. This method is not only suitable for a wide range of asphalt types, but also provides reliable data support for subsequent applications in highway engineering and related fields. In the future, the specimen preparation process should be continuously optimized to further improve the accuracy and practicability of detection.
