Structure and artificial ageing behavior of organo montmorillonite bitumen nanocomposites

This paper studied the structure and ageing behaviors of bitumen modified with organo montmorillonite (OMt). Two OMt with different surfactants were used to modify one base bitumen using a laboratory high-shear mixer. The rolling thin film oven test and the pressure air oven test were performed to simulate the short term (ST) and long term (LT) ageing on the bitumen, respectively. The structures of OMt were determined by X-ray diffraction, fluorescence microscopy and computed tomography (CT) scanning. The ageing behaviors were evaluated with a dynamic shear rheometer. The intercalated structure of both OMt was observed in the bituminous matrix. This structure improved the ST ageing behaviors of bitumen. With respect to the LT ageing, an automatic accumulation of OMt particles took place under the tough artificial ageing conditions, and consequently led to a less improvement in the ageing behavior.

► An intercalated structure of organo-montmorillonite (OMt) in bitumen was observed.
► Rheological property change of bitumen is related to the surfactant type on OMt.
► The addition of OMt can improve the short term ageing resistance of modified bitumen.
► An automatic accumulation of OMt particles could take place during the long ageing test and consequently limit the improvement in the long ageing resistance of modified bitumen.