Evaluation of the effects of compaction methods on the predicted performance of Superpave mixtures.

摘要

Several compaction methods are used to fabricate specimens for performance testing in the laboratory. As the physical properties of the specimens depend on the method of compaction used for fabrication, the compaction methods adopted in the laboratory should simulate the properties of the pavement in the field. The effects of different compaction methods on the performance of mixtures were investigated in this study. Laboratory compaction methods such as Superpave Gyratory Compaction (SGC) and Rolling Wheel Compaction (RWC) were compared with field compaction. Four field mixtures were selected. Various performance evaluation tests were conducted on the field cores and specimens fabricated using SGC and RWC. The mixtures were evaluated using the Shear tester, the Asphalt Pavement Analyzer (APA) and the NCSU Wheel Tracking Device.; The results indicate that the laboratory compacted mixtures tend to be superior in their performance than the field cores. The laboratory compacted mixtures have higher stiffness values and lower shear strain values than the field cores. The RWC seems to simulate field compaction better than the SGC. A good correlation was found between the results of the Repeated Shear tests at Constant Height tests, the APA tests and the NCSU WTD rut tests. The mixtures which failed to satisfy the RSCH test criteria had rut depths greater than 0.5 inch, as measured by the APA and NCSU WTD. The mixtures that passed the RSCH tests had rut depths less than 0.5 inch. The APA test and the NCSU WTD test can be used as a simulator to examine the rutting susceptibility of a mixture.; The compactability of the mixtures is studied using the SGC, IPC Servopac Compactor and GLPA. The compaction parameters that relate with the rutting behavior of mixtures were compared with the RSCH shear strains at different air void contents. The correlations showed different trends with two sets of parameters with one set measuring the compactability of the mixtures and another set measuring the shear behavior of the mixtures. The compaction parameters measured based on the theory of rate of densification could not satisfactorily predict the rutting behavior of the mixtures.