The dynamic viscosity test of asphalt is designed to determine the dynamic viscosity of viscous petroleum asphalt and is suitable for various asphalt materials. The test is usually performed at a temperature of 60 °C with a vacuum of 40 kPa. This method provides a scientific basis for evaluating the fluidity and properties of asphalt under different conditions, especially in road construction and material design.
Technical requirements for instruments and materials
Vacuum-decompressed capillary viscometer
Vacuum decompression capillary viscometer is used, and common models include United States Asphalt Society type (AI type), Cannon Manning type (CM type) and modified campein type (MK type). The instrument must meet the standard size and shape requirements.
thermometer
A thermometer with a range of 50~100°C and a graduation value of 0.1°C should be used to ensure the accuracy of temperature measurement.
Thermostatic sink
The thermostatic sink should be equipped with heating and automatic temperature control to keep the test temperature within the range of ±0.1°C. The temperature difference between different locations in the sink must not exceed ±0.1°C.
Vacuum decompression system
The vacuum system should be able to ensure a vacuum level of 40 kPa ± 66.5 Pa, and the connections must be sealed to prevent air leakage.
stopwatch
A minimum of two stopwatches with an accuracy of 0.1 seconds and a total range of no more than 15 minutes are required.
oven
It should be equipped with an automatic temperature controller to facilitate uniform heating of the specimen.
solvent
Use solvents such as chemically pure trichloroethylene to clean the equipment.
Other materials
Including auxiliary materials such as lotion and distilled water.
Methods and Steps:
Preparation
Select the appropriate capillary viscometer and estimate whether the flow time required is more than 60 seconds based on the viscosity of the sample.
Use a solvent such as trichloroethylene to clean the capillary tube to ensure that there is no oil stain.
Prepare the asphalt sample, heat and stir it sufficiently to ensure good flowability.
Set the thermostatic sink to 60°C±0.1°C and calibrate the thermometer.
Test procedure
1. Inject the hot asphalt specimen into the capillary viscometer and adjust it to the E mark.
2. Place the viscometer in the oven and keep warm for 10 minutes to allow air bubbles to escape.
3. Remove the viscometer from the oven, cool it and place it in a Thermostatic Water Bath.
4. Connect the vacuum system and turn on the pump to vacuum to the set value.
5. After 30 minutes, record the time for the sample to pass through the reticle.
Washing steps
Drain the bitumen out of the capillary tube in an oven at 135°C and avoid scorching for too long.
Wash the capillary with solvent until it is clear and transparent, and finally rinse with distilled water.
Data calculation and reporting
The test results should be tested in parallel, and the error of the measurement results of the three viscometers should not exceed 7%. If the requirements are met, the average of the three results is taken as the final measured value. The permissible errors for the repeatability test and the reproducibility test were 7% and 10%, respectively.
conclusion
Asphalt dynamic viscosity testing is a key test method to effectively evaluate the flow and physical properties of asphalt. Reliable viscosity data can be obtained by vacuum decompression capillary method, which provides a scientific basis for the application and selection of asphalt materials. The standardized operation of this method ensures the accuracy and repeatability of the test results, which is suitable for the performance evaluation of different types of asphalt.
summary
The dynamic viscosity test of asphalt is used to determine the dynamic viscosity of viscous petroleum asphalt by vacuum decompression capillary method, which is often used to evaluate the fluidity and physical properties of asphalt. The test was carried out at 60 °C and 40 kPa under vacuum, using specific instruments such as a capillary viscometer and a Thermostatic Water Bath. The test process includes steps such as sample preparation, constant temperature insulation, vacuum measurement, etc., and requires a thorough cleaning of the instrument. By accurately calculating the flow time of the sample, the dynamic viscosity value can be obtained, which provides a scientific basis for the selection of asphalt materials in road construction and other fields. This method is highly reproducible and reliable, and meets industry standards.
