Metodik för utmattning av asfaltbruk
Sammanfattning: The durability of asphalt can be investigated with fatigue tests, which unfortunately are very laborious and costly. Therefore, they are not used as often as they should. At LTH in Lund, an alternative method is utilized using a dynamic shear rheometer, DSR, on asphalt’s mastic for fatigue properties testing. The properties of asphalt mastic are crucial for the asphalt pavements ability to withstand repeated loads. Fatigue fracture is a well-known phenomenon and affects all types of materials. The method, using DSR for fatigue testing is new and needs to be evaluated. A crucial impetus came from TUW, Technische Universität Wien, who launched a version that is now being further developed at LTH. DSR is usually used to investigate pure bitumen, but several theses at LTH have been investigating mastics in a similar way, inspired by the American asphalt concept Superpave. Commonly rutting and low temperature properties are investigated with DSR on asphalt mastics. Fatigue testing with DSR may complement these tests. After developing a first operating scheme, various asphalt compositions with both standard bitumen and polymer modified bitumen were tested. The results showed that the test might order the fatigue properties in a logical order. Unfortunately, a considerable time was spent on preparing the operating schedule, meaning that only single and few measurements could be carried out. Nevertheless, surprisingly only a few results fell outside the expected outcome. Further studies should focus on to streamline the process, investigate precision data and finally conduct parallel studies with the conventional fatigue test methods to examine the validity of the test.
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