National Standard for Highway Instruments Asphalt Low Temperature Elongation Tester

　　Ductility is one of the three major indicators to measure the properties of asphalt, usually expressed as the ductility of asphalt. An asphalt sample of a certain geometric shape and size is placed in a specified water medium, stretched at a constant speed, and the length when it is pulled apart is measured, which is called the ductility of asphalt and is expressed in millimeters.

　　This instrument is suitable for measuring the elongation of various types of asphalt, liquid asphalt distillation residues and emulsified asphalt evaporation residues and modified asphalt and other materials. It is widely used in production, road construction and scientific research departments.

　　2. Structural principle and characteristics of the instrument

　　The appearance of the asphalt elongation meter is elegant and refined. Its durability is fully considered. The inner tank is equipped with an electric heating tube and a set of refrigerators. The internal screen or computer is used to collect and control data, and it is automatic and convenient to save data. The frequency conversion control technology, the box body is made of imported stainless steel with exquisite bending, and the LCD controls the double screw rod, with high displacement movement accuracy, high safety and reliability. It can move from one end to the other at a constant speed of 5cm per minute, and the standard specimen in the test mold is broken at a constant speed in the water tank to obtain the elongation value of the specimen.

　　The digital temperature controller can directly control the heating and cooling systems. The water temperature in the water tank is adjustable at 0-50℃, and is equipped with a diversion circulating water system, which can effectively balance the water temperature.

　　The digital display of the elongation meter can directly display the extension length and automatically calculate the average elongation of three samples at the same time. It has the advantages of easy use, stable traction speed, small vibration and low noise.

　　3. Main technical indicators of asphalt elongation meter

　　1. Working voltage 220V±10% 50Hz±0.5Hz

　　2. Ambient temperature: 0~30℃

　　3. Temperature control accuracy ±0.5℃

　　4. Relative humidity (at 25°C) < 80%

　　5. Refrigeration power 1.2KW

　　6. Maximum extension: 150CM, 200CM

　　7. Heating power 1.5KW (1KW)

    8. Extension speed 5±0.25cm/min

　　9. Elongation measurement indication error ±0.5%

　　10. Overall dimensions: 1.5 type: 2340×810×670 (mm)

　　Type 2 2840×810×670 (mm)

　　4. Asphalt elongation tester test method and precautions

　　1. Preparation

　　(1) First, mix the release agent evenly and apply it on the bottom plate of the 8-shaped test mold and the inner side of the 8-shaped test mold. Then, assemble the test molds into an 8-shaped shape and place them on the bottom plate of the test mold.

　　(2) Heat the dehydrated sample, sieve it, and stir it thoroughly until the bubbles are completely expelled. Then move the sample back and forth from one end of the test mold to the other end several times, and slowly inject it into the test mold and slightly protrude it above the mold.

　　(3) After the sample has cooled at room temperature for 30 minutes, it is placed in water at the specified test temperature for 30 minutes. The sample is then taken out and the asphalt that protrudes above the mold is scraped off with a hot scraper, making sure that the asphalt is aligned with the test mold.

　　(4) Place the specimen together with the test mold base in a water tank maintained at the specified test temperature for 1-1.5 hours.

　　(II) Test steps

　　(1) The asphalt elongation meter should be placed horizontally indoors at a temperature of 0-40°C, relative humidity not exceeding 80%, on a ground free of vibration and corrosive gases, and should have good grounding protection.

　　(2) Before use, check the water level in the water tank to ensure that it complies with the test operating procedures. After turning off all function switches, turn on the power supply and check whether the stirring motor and the extended power motor are operating properly.

　　(3) Adjust the temperature controller to the required temperature, start the refrigeration or heating system function switch, and start the stirring motor at the same time. (Note: The stirring motor should be turned off to stop water circulation at the beginning of the test)

　　Microcomputer control interface

　　Open the software and you will be taken to the above interface.

    1: First select the serial port. In general, the default is COM1. Click to accept data. If the communication indicator turns green, it means that the computer and the control system have established a connection and data transmission and control operations can be performed. [page]

　　In the upper left corner of the interface are some current data displayed, which are collected and displayed in real time.

　　The curve display of the whole process can be seen on the elongation-tension curve.

　　2: Press the "Calibrate" key to calibrate the full scale pressure: enter the password 1110, enter the full scale pressure calibration, add pressure to make the force ring equal to the standard value, and press to confirm and return.

　　3: Press the "Parameter Setting" key to set the test parameters: change the full-scale data coefficient so that the tension display is equal to the standard value of the force ring and the standard value of the force ring, then press the "Confirm" key to save. When all test parameters are set, return to the initial interface.

　　4: Press the "Speed" key and the speed can be switched between 50 mm/min and 10 mm/min.

　　5: Test: Press the start key, the instrument starts counting, when the counting key is pressed for the first time, the value 1 is kept, when the counting key is pressed for the second time, the value 2 is kept, when the counting key is pressed for the third time, the value 3 is kept, and the average elongation value and the maximum tension, group number are displayed. At this time, press the print key. The test number can be printed. Press the "water pump" key to switch the water pump on and off.

　　6: Press the "Back" key to reverse the motor. When the reverse limit switch is closed or the "Counting Key" is pressed, the motor stops reversing.

　　7: Query: When you just enter the startup interface and when the test is finished, press the "Query" key and enter the query group number (1-20). Press the SET key to enter, then you can press the shift key to display the test curve of the current query group, press the SET key to view the test data of the next group, and press the "Query" key to return.

　　(During the query process, you can press the "Print" key to print the experimental data corresponding to the query group number)

　　(4) Adjust the temperature controller to the required temperature, start the refrigeration or heating system function switch, and start the stirring motor at the same time. (Note: The stirring motor should be turned off to stop water circulation at the beginning of the test)

　　LCD screen operation

　　1: Pressure 0 point calibration: On the power-on interface, press the Clear key to complete the pressure 0 point calibration.

　　2: Calibration of full pressure range: Press the shift key for 5 seconds, enter the password 1110, press the SET key to enter the full pressure range calibration, and when the pressure is increased to make the force ring equal to the standard value, press the SET key to confirm and return.

    3: Test parameter setting: Press the SET key to change the full-scale data coefficient so that the tension display is equal to the standard value of the force ring and the standard value of the force ring, then press the SET key to save. When all test parameters are set, return to the initial interface.

　　4: Press the "Speed" key and the speed can be switched between 50 mm/min and 10 mm/min.

　　5: Experiment

　　Press the start key, the instrument starts counting, when the counting key is pressed for the first time, the value 1 is kept, when the counting key is pressed for the second time, the value 2 is kept, when the counting key is pressed for the third time, the value 3 is kept, and the average elongation value and the maximum tension, group number are displayed. At this time, press the print key to print the test number.

　　Press the down key to switch the water pump on and off.

　　6: Press the "Back" key to reverse the motor. When the reverse limit switch is closed or the "Counting Key" is pressed, the motor stops reversing.

　　7: Query

　　When you just enter the startup interface and the test is finished, press the "Query" key and enter the query group number (1-20). Press the SET key to enter, then you can press the shift key to display the test curve of the current query group, press the SET key to view the test data of the next group, and press the "Query" key to return.

　　(During the query process, you can press the "Print" key to print the experimental data corresponding to the query group number)

　　(5) Connect the power supply of the digital display device on the gearbox, turn on the start switch, the instrument starts working, and the display will show the extension length. During the test, if asphalt filaments are found floating on the water surface or sinking to the bottom of the tank, add alcohol or salt to adjust the specific gravity of the water to be close to that of the sample, and then conduct the test again.

　　(6) When the asphalt sample breaks or meets the test requirements, press the value switch and the instrument will automatically count the elongation of the sample. When the second sample breaks, press the value switch again and the instrument will automatically count the elongation of the sample. After the third sample breaks, press the value switch again and the instrument will automatically calculate and display the average value of the three samples.

　　(7) After the work is completed, turn off the power, take out the test mold, pull out the handle 4 to neutral position, and push the gearbox back.

　　(8) Open the drain valve, drain the water in the tank, wipe it dry, and add appropriate amount of engine oil to each transmission part and gear to prevent rust.

　　(9) If the motor is used frequently, open the four bolts on the motor every six months and grease all the parts in the gearbox. If it is not used for a long time, it must be covered with a dust cover to prevent dust.

　　(10) It is strictly forbidden to turn on the heating switch or refrigeration system when there is no water in the sink.

    5. Notes on Asphalt Elongation Tester

　　1. The instrument must use a standard socket with good grounding protection.

　　2. The voltage of the instrument should be within the specified voltage range. If the voltage is unstable, a voltage stabilizer should be installed.

　　3. There is a time delay protection device when the instrument is turned on, which is not a fault.

　　4. If the refrigerator has not been used for a long time or is used for the first time, the condenser fan should be checked to ensure that it is working properly, otherwise it will cause compressor failure.

　　5. After using the instrument, please drain the water and then turn on the stirring water pump again to drain the accumulated water in the pump to prevent blocking.

　　6. After using the instrument, first turn off all function switches, and then turn off the main power switch.