Views:1 Author:Site Editor Publish Time: 2020-07-13 Origin:Site
Chocolate pudding, synthetic rubber, toothpaste and asphalt… At first glance, these items seem to be randomly selected. Although it may not be obvious, these products have a common, basic characteristic-their rheology, or flow and deformation, can be measured with one instrument.
1. measure flow and deformation characteristics
2. monitor the consistency
3. determine rheological properties
Asphalt binder tester measures flow and deformation characteristics. It can be in the form of any instrument that can apply prescribed stress (the force required to generate flow and deformation) or strain (deformation caused by flow), and then measure the resulting stress or strain. If the electronic monitoring of stress and strain match during a wrestling, the opponent and the monitoring system would constitute a rough rheometer. Fortunately, there is now a more accurate way to measure material flow and deformation.
Some early adopters of the asphalt binder tester were scientists in the food industry. By studying changes in rheological properties from one production batch to the next, it is possible to monitor the consistency of foods such as ketchup. Asphalt binder tester is designed to accurately measure the vibration and stress and strain of various materials under different temperatures, stable shear and repetitive loads, becoming a useful scientific tool in industry.
After reviewing the equipment specifications, the developers recognized the need to determine rheological properties at moderate temperatures. The problem is that the stiffness of asphalt binders is usually so high that by using the same parallel plate geometry and using 25 mm diameter plates at high temperatures, the torque capacity of the asphalt binder tester will have to be greatly increased. Under the same conditions, the torque required to determine the stiffness of the asphalt binder at moderate temperatures may be 100 to 1000 times the torque required at high temperatures!
In order for the asphalt binder tester to be an affordable, compliant device, designers must either "increase" torque or find ways to reduce demand. Since the measured complex modulus G is a function of the fourth power of the radius of the sample, small changes in the size of the parallel plate can greatly reduce the torque requirement. By reducing the size of the plate to one-third (25 mm) of the original size, the torque required for an 8 mm diameter plate is approximately 100 times lower than that required for a 25 mm diameter plate.
Although the torque problem seemed to be resolved, the technicians found that using smaller plates at moderate temperatures produced more variable test results than using larger parallel plates at high temperatures. This variability is partly due to the increased throughput of the asphalt binder tester aging process. Using two aging procedures, a rolling film oven and a pressure aging container, at intermediate temperatures before testing on asphalt binders, the chance of error increases. Murphy's Law tells us a lot. Another challenge with increasing variability is testing variables. Smaller plates mean more important trimming. Trimming errors increase rapidly.
The acceptable range of the intermediate temperature asphalt binder tester test results from two different laboratories is 40%. This means that if a laboratory tests asphalt binders and obtains a specification value of 3700 kPa at 22 ° C, then it can be assumed that the material is within the specification range and has a long service life. If the same asphalt binder tester is provided to the user and his laboratory tests a sample of the asphalt binder, he can get a specification value at 22 ° C, which is as high as 5500 kPa, and is still being tested. The problem is that in the Performance Graded (PG) asphalt binder specification, one specification value of 5500 kPa fails, while the other result (3700 kPa) is easily passed.
In other words, suppose you bought a car and the fuel consumption listed above is 30 miles per gallon. After driving for a while, you'll find that it doesn't seem to reach 30 miles per gallon; roughly 20 miles per gallon. So you go online and do some research and find that asphalt binder tester result reported by the manufacturer is 30 miles per gallon, and the test result reported by an independent laboratory is 20 miles per gallon. If the test variability is as high as 40% of our intermediate asphalt binder tester value, then these two fuel consumption tests will be considered to be of the same statistical significance.