Several Key Features of the Asphalt Mixture Stability Tester

　　To achieve the above-mentioned objectives, this utility model adopts the following technical approach:
　　An automatic digital-display installation for testing the Marshall stability and flow values of high-strength asphalt mixtures, characterized by comprising a digital-display pressure testing machine, two Marshall test molds, shims, a flow-value sensor, and a signal switch. Specifically, the two Marshall test molds are installed directly above the center of gravity of the lower platen of the digital-display pressure testing machine and below the upper platen of the same machine. The two Marshall test molds are stacked one on top of the other, forming a cylindrical cavity. The flow-value sensor is positioned on top of the Marshall test mold. The flow-value sensor, the digital display screen of the digital-display pressure testing machine, and the hydraulic sensor are each connected to the signal switch. A shim is placed between the upper Marshall test mold and the upper platen of the digital-display pressure testing machine.
　　Operating Procedures
　　Special instrument inspection and metrological calibration
　　After powering on the instrument, turn off the power switch on the control box, then press the stop button on the front panel of the instrument chassis. At the same time, flip on the power switch of the instrument chassis. You’ll hear a single “beep,” indicating that the instrument has entered the inspection and calibration procedure. At this point, the pressure and displacement windows should display “000” (if the zero-point adjustment is available, you can adjust the pressure zero-position potentiometer on the rear panel). Once this is done, you can stop the displacement indicator.
　　Displacement calibration
　　Place the displacement device on a relatively stable workbench, align it with the scale markings, and push it inward until it reaches the second marking line. The reading displayed in the flow-value window should change accordingly. After completing the inspection, be sure to turn off the machine and then restart it before resuming normal measurements. Note: Under no circumstances should you use the inspection and calibration procedures to interrupt or terminate normal operation or testing. Normal experiments are equipped with over-maintenance protection features, whereas calibration procedures add additional maintenance functions—please pay close attention to this distinction.
　　Normal experiment
　　After the power is turned on and the preheating phase is complete, you can start the experiment once you hear the internal buzzer sound. Once the specimen reaches its peak load, the machine will automatically begin lowering. The descent takes 30 seconds, and you can use the setting key to adjust the duration of the descent. When one specimen’s experiment is completed and both the peak load and displacement values have been locked, the main unit will start descending. After the descent stops, if you need to print a report or generate a graph, simply press the Print key. Be sure to connect the printer beforehand.