The purpose of this study was to investigate methods for the determination of bitumen floating, with a focus on sample preparation and temperature control during distillation tests. The reliability of the test results is improved by detailing the experimental procedure to ensure that the floatation determination is carried out under precise temperature control. In addition, the influence of different test conditions on the results is analyzed, and the allowable error of the measurement results is discussed, so as to provide a scientific basis for the evaluation of asphalt performance.
The bitumen float test is used to determine the softening characteristics of bitumen at a specified temperature. Specifically, floatation refers to the ability of an asphalt specimen to gradually soften in a tank at a certain temperature until it is broken by water. This indicator is essential for evaluating the performance of asphalt in real-world applications, especially in road construction and maintenance. The test is suitable for the determination of the float degree of liquid petroleum asphalt and coal pitch and other materials, the test temperature of the residue after distillation of liquid petroleum asphalt is generally 50 °C, and the test temperature of coal pitch is usually 32 °C or 50 °C.
Floatation Instrument – A combination of copper tube and float disc with specific wall thickness and size.
Sink - at least 185mm in diameter, not less than 185mm in depth, can maintain a water temperature of 5°C ±1°C.
Thermometer - used to accurately measure water temperature, measuring range 0~100°C.
Other equipment – heating furnace, glycerin talc separator, scraper, ice cubes, alcohol lamp, etc.
Preparation
1. Apply glycerin talc release agent to the copper or glass plate and place the copper tube on it.
2. Prepare the asphalt specimen according to the procedure, fill it with copper pipes, and cool the specimen to room temperature.
3. Adjust the water temperature of the sink to 5°C±1°C.
Test procedure
1. Tighten the copper tube to the bottom hole of the floating dish and re-place it in water at 5°C for 1 minute.
2. Remove the float instrument and quickly dry it, place it in a sink to maintain the test temperature, and start the stopwatch at the same time.
3. Observe the process of the specimen softening and being washed by water, and record the time to the second.
At least two parallel trials were conducted, and their average values were taken as test results. If the difference in the result is not more than 4 seconds, it is acceptable.
The purpose of this test is to determine the fraction content of liquid petroleum asphalt and provide a basis for further physical property testing (such as viscosity, floating, etc.). Standard distillation switching temperatures are 225°C, 316°C and 360°C.
Distillation flasks – made in standard shapes and sizes.
Insulation hood – lined with asbestos to maintain temperature.
Condenser tubes and guide tubes – for the export of liquids in the distillation process.
Other equipment – thermometers, graduated cylinders, iron frames, etc.
Preparation
1. Wash and dry all instruments.
2. The asphalt sample is evenly heated and injected into the weighed distillation flask to ensure that the quality meets the requirements.
3. Assemble the distillation equipment, connect the condenser tube and connect the water source.
Test procedure
1. Heat the distillation flask evenly so that the first drop of distillate should be dropping between 5 and 15 minutes.
2. Adjust the heating temperature to ensure that the distillation speed meets the standard.
3. When the specified temperature is reached, accurately record the fraction volume and keep the distillation temperature to 360°C before stopping the heating.
Again, at least two parallel trials should be performed, and the average of them should be taken as results. The influence of altitude on the distillation temperature should be taken into account during the test, and temperature correction should be made if necessary.
The float of asphalt and the distillation test of liquid petroleum asphalt are important material testing methods, which provide a scientific basis for the performance evaluation of asphalt. These tests ensure the reliability and safety of asphalt in engineering applications, so the relevant testing standards and methods must be strictly followed in the production and application of asphalt.