| Autor: |
Zhai, Huachun, Bahia, Hussain U., Erickson, Signe |
| Zdroj: |
Transportation Research Record; January 2000, Vol. 1728 Issue: 1 p7-14, 8p |
| Abstrakt: |
In the current Superpave® binder tests, the rheological properties of asphalt binders are determined by the dynamic shear rheometer. The asphalt binders are tested using a gap size of either 1 or 2 mm. In the asphalt mixture, the thickness of the asphalt film between aggregates can vary between a few microns and a few millimeters. Because of the interaction between the asphalt and the aggregate, rheological behavior in thin films can differ from the behavior determined at large gap sizes. In this study the rheological properties of asphalt binders were measured at different gap sizes that simulate the range in film thickness of a typical mixture. Significant changes in rheological properties were observed as the gap size changed. The results indicate that different modified binders show different trends as the gap size changes. A review of the literature was conducted for an explanation of this behavior. Four mechanisms were offered to explain similar gap effects observed for other materials. Using the data collected in this study, the disentanglement mechanism caused by adhesion to testing plates appears to fit the observations for asphalt binders. The results suggest that the current gap settings in the binder tests might not be sufficient to determine the performance of the binder in the mixture. The findings also suggest that more work is required to understand the effect on the rheological behavior of asphalt binders of physical and chemical interactions with aggregates. |
| Databáze: |
Supplemental Index |
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