Research on Evaluating Method and WRI of Asphalt Mixture

This paper studied the high temperature stability of the HMA(hot mixed asphalt) to the same aggregate gradation by rutting test. It is pointed that traditional dynamic stability (DS) index for evaluating the high temperature stability of the HMA can not cover the permanent deformation resistance throughout the whole pavement service life, sometimes the rut is still too deep to tolerate although the DS is relatively high. Therefore wheel rutting index(WRI),a new index for evaluating the whole term high temperature stability is presented in this paper. It combines the influence factors of velocity, cumulate deformation and maximal permanent deformation. The results indicate: Analysis of the degree of track rut in different period shows that the calculation of DS only considers the deformation ratio of 15min after the HMA is compacted, overlooking the maximum deformation and the development of deformation in the entire process, thus limits the DS to a great degree to value the stability of HMA. That the WRI is accord with the rut formation regular in project, WRI reflects the development of rut in pavements, and has an effectual distinction for evaluating the high temperature stability of the HMA, so is more effective in differentiate the stability property of HMA.