NANOSILICA AGGLOMERATION AND RHEOLOGICAL PROPERTIES OF BITUMEN

抄録

 Nanosilica (NS) is available in various types or sizes and has been the focus of many research attempts on bitumen. However, most of the publications have failed to acknowledge or implement the effects of the NS type itself. The tendency for clustering in NS particles induces large lumps rather the fine particles, which impacts all the bitumen properties. Likewise, the dimension of clusters should be minimised by the appropriate selection of NS size and mixing conditions. Cryogenic SEM is a versatile tool to track the size of clusters, so it was employed here to visualise the changes in intact bituminous samples. This study introduced three NS types, 20–30 nm, 60–70 nm, and 20–30 nm with couplant, to the class C320 bitumen at dry and wet mixing conditions. Captured images were processed by ImageJ software to examine the status of clusters for various mixtures. Frequency sweep DSR tests and column chromatography were also undertaken to determine the likely relationships of bitumen properties at the nano to macro levels. It is found that, the NS type directly affects the average size of clusters, consequently, the rutting and fatigue performances of the binder. In addition, 60nm NS demonstrated the smallest size of clusters with better performances than other NS types.