| Rutting test, because of its simple operation and easy calculation, is widely used as the test methods way to detect the optimum asphalt content of asphalt mixture (AM) by many countries.In China, it is mainly used as one of the test methods to evaluate the high temperature stability (HTS) of AM, and the evaluation index is dynamic stability (DS).But this index is not comprehensive enough to consider the rolling process, and sometimes when the DS is same, the deformation is-different greatly. In order to find a better index to evaluate the HTS of AM, this paper, which is on the basis of rutting test and through the coordinate transformation of the deformation curve and regression analysis, reaches a new index-modified dynamic stability (MDS).The content of this study and the results achieved are as follows:(1)Through the method of volume design, two asphalt mixtures of AC-16and AC-20have been designed. And the VV of AC-16is4%, and the VMA is13.5%-16%.The VV of AC-20is4%and5%, VMA is1-5%and16%.(2) By comparison and analysis of the existing lacks of evaluation index of DS, relative deformation rate (δ) and deformation index (rutting depth, RD), this article focuses on the need for new indicators. During the analysis of rutting deformation curve, this paper implements a computer applied algorithm to prevent deformation wave from the individual time point, keeping the right of the results, picking up the deformation and corresponding time point, repainting the rutting deformation curve and doing researches on coordinate transformation and regression analysis to deformation. It is concluded that AM has entered into the stability period when the time of test is about36min. Then deduce the new index MDS.(3)Under the different VMA, nominal size and load pressure, MDS, DS and RD are used to evaluate the HTS of AM. It shows that the evaluate results of the MDS is closer to the actual performance. Therefore, MDS is more reasonable as the evaluation index. |
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