عنوان مقاله [English]
The main objective of the present study was to conduct a comparative test program on unmodified bitumen and modified bitumen containing nanoclay and assess the effects of asphalt properties on pavement performance. To meet this objective, the main targets of this study are to find out if the nanoclays alter the critical properties of asphalt binder and influence the ageing and temperature sensitivity of the binder. Different tasks were performed to meet the objectives. The first task performed was studying the nanoclay modifiers at a nanoscopic level and the test performed in this area was the X ray analysis of the nanoclay modifiers. The second task was studying the influence of nanoclay modifiers on binder characteristics and the related tests performed were empirical studies of fresh (unaged) and aged bitumen types by empirical tests like penetration and softening points. Findings of the tests performed on binders proved that the cloisite-15A nanoclay modifications helped to increase the stiffness of the standard binder. This was especially true if the 4% cloisite modification was used. The nanofil-15 modification helps to improve the ageing resistance of the binder in short and long term applications. An overall conclusion from these findings is that the nanoclay modifications help to improve some characteristics of asphalt binders and asphalt mixtures, but at this level they are not at a stage to justify applications on large scales.