A Dynamic Loading Test for Evaluating Permanent Deformation Resistance of Asphalt Mixtures

摘要

Recent research shows that there is a serious need for accurate methods to evaluate the deformation resistance of asphalt mixtures at high temperatures, especially for stone-skeleton mixtures. To reflect the interlocking angle between coarse aggregates, confining pressure should be considered during testing. The dynamic loading test has been developed for applying different repetitive loads to a limited area of the specimen. This test can measure permanent deformation indices under different loads to evaluate the deformation resistance of asphalt mixtures at high temperature. The dynamic loading test is conducted on samples with different compaction rates and gradations. Further, the rutting resistance of two types of gradation is compared with a wheel tracking test and a dynamic loading test. The test results indicate that the dynamic loading test can apparently distinguish the influence of gradations on rutting resistance. It is also derived from this test that dense-graded mixtures have higher permanent deformation susceptibility than coarse-graded mixtures, which is consistent with experience in the field and validated by experiments. This test can reflect the entire permanent deformation and separate the compactive deformation and shear flow deformation. Furthermore, this test can simulate heavy and repeated loads to fully exhibit the deformation resistance of asphalt mixtures, especially for coarse-graded mixtures. However, this test is limited by the effects of rigid confinement, which can be improved by changing the confining pressure.