Laboratory Study of the Effects of Compaction on the Volumetric and Rutting Properties of CRM Asphalt Mixtures

摘要

The compaction conditions (e.g., compaction temperature and compaction level) of crumb rubber modified (CRM) asphalt mixtures should be determined carefully because the viscosity and amount of the CRM binder affects the compactability of the mixtures. Furthermore, the properties of CRM mixtures relating to the compaction conditions have not been studied in great detail. In this study, a laboratory investigation was conducted on the volumetric and rutting properties of CRM mixtures as a function of compaction conditions. For this research work, four Superpave mix designs for four different asphalt binders (control, SBS modified, 10% rubber modified, and 15% rubber modified) were carried out to determine the optimum asphalt contents. A total of 260 specimens were fabricated using the Superpave gyratory compactor at four compaction temperatures (116, 135, 154, and 173℃) and five compaction levels (20, 40, 60, 80, and 100 gyrations). The volumetric properties were obtained and analyzed, and the rutting resistance of the mixtures was measured using the asphalt pavement analyzer. The results from this study indicated that: (1) the compaction temperatures used in this study significantly affected the volumetric properties of the CRM mixtures, unlike the control and SBS-modified mixtures; (2) in general, the air void contents of the mixtures were significantly influenced by the compaction levels; and (3) as expected, the higher air void contents of the CRM mixtures seemed to have a detrimental effect on the rutting resistance.