Rubber swelling plays an important role in the property development of rubberized binders during bitumen-rubber interactions. Laboratory tests have shown that swelling of rubber in bitumen is a Multiphysics phenomenon which consists of liquid diffusion and solid volume expansion. Finite element model of rubber swelling was built to couple the above physics. The swelling process of rubber in bitumen was visualized using FEM software COMSOL. It was confirmed that rubber swelling is time and temperature dependent. More accurate model inputs and simulation at various interaction conditions will provide guidelines for material selection and sample preparation. ... Read more

The continuous increasing demand of public transportation capacity requires the railway network operating in tight schedule. The high transporting volumes not only aggravate the degradation of railway infrastructure but also shorten the time fo r maintenance. Well-arranged infrastructure maintenance contributes to the budget reduction and reliability improvement. With the purpose of key parameters investigation in the turnout crossing degradation process, a series of subsequent measurements using instrumented crossing system (ESAH-M) on a 1:15 railway turnout at various stages were performed. The results indicate that wheel/rail impact area narrowed with deepened rail wear. This narrowing is a signal of rail damage. Frequency band pass filtered results describe the condition development of different structures in the turnout crossing section in the test period. Series of mo re systematic crossing measurements are in progress in a test section in the Netherlands. The ultimate purpose of this study is to form the crossing degradation function to be implemented in the structural health monitoring system (SHMS) for railway turnouts developed at the TU Delft. ... Read more