Introduction to Knowledge About Stability Instruments

Introduction to the relevant knowledge about stability meters.

　　Main features of the stability meter:

　　1. It can achieve automatic counting, automatic compaction, and automatic shutdown.

　　2. Equipped with a hammer holder and a manual handle, allowing the hammer to be lifted easily.

　　3. Semi-automatic molding device, making it easier to load and unload molds.

　　4. The one-piece hammer head will not fall off, break, or crack.

　　So, how do you operate and use a stability meter?

　　Preparation/About to start work:

　　1. Determine the compaction temperature of the asphalt mixture specimen.

　　2. Mix the asphalt mixture using a fully automatic mixing machine.

　　3. Wipe the test mold, sleeve, and compression seat with cotton gauze lightly coated with butter, then heat them in an oven at approximately 100°C for 1 hour and set aside for later use.

　　Usage steps:

　　1. Add the heated mixture into the test mold. Insert a thermometer near the center of the mixture. Once the temperature meets the required specifications, place a round paper with low oil absorption on top of the loaded mixture, then insert the compaction head—equipped with a rammer and guide rod—into the test mold.

　　2. Turn the “Preset” knob to set the desired number of compaction cycles as needed. Press the “Set Number” button, and the preset number will be displayed in the window. Press the “Start” key, and the motor will begin rotating. Once the specified number of compaction cycles is reached, the window will display “00,” and the motor will automatically stop.

　　3. After compacting one side of the specimen, remove the sleeve, flip the mold over, reattach the sleeve, and then compact the other side using the same method and number of passes.

　　4. After the specimen has been compacted, immediately remove the top and bottom papers using tweezers and measure the specimen’s height with calipers. Specimens that do not meet the requirements shall be discarded. If the specimens meet the requirements, remove the sleeve and base, allow them to stand at room temperature for 12 hours, and then use a demolding machine to extract the specimens.

The stability tester is primarily used to determine the thermal stability and resistance to plastic deformation—specifically, the stability and flow value—of asphalt mixtures. It provides an accurate basis for the design of asphalt mixture compositions. The stability tester is also one of the commonly used pieces of equipment in our laboratory.

　　The stability tester is equipped with overload protection and overtravel protection, features simple operation, accurate test data, and stable and reliable performance. The instrument automatically tests, displays, and prints stability values as well as corresponding flow rates, and plots coordinate curves showing the stress and deformation of the specimen. It can store the test results from up to 15 planned test sequences. A large LCD screen displays the stability curve and flow rate in real time. The instrument also includes a manual lifting function, allowing the platform to be positioned precisely. Flow rate detection is available in both single-channel and dual-channel modes.

The stability tester is controlled and displayed by a digital tube, capable of automatic lifting and lowering, automatic completion of the entire testing process, and automatic display of test pressure and flow rate values. It can serve as a small Marshall specimen holder. A miniature printer is included to print test data and small-scale charts. This device can be used both for small Marshall specimens and for large Marshall specimens—just like other similar devices. The stability tester can display graphical curves showing the progress of the test, the data trends, and the values of pressure and flow rate. It also comes equipped with an A4-paper printer that can produce detailed graphs of the test results, data trends, and pressure/flow rate values. Additionally, the tester features a serial port and can connect to a computer network.