Rheological and anti-moisture characteristics of rubberized reclaimed asphalt pavement with interfacial bond behavior

The application of recycled materials in terms of reclaimed asphalt pavement (RAP) and crumb rubber, as an environmental-friendly and sustainable strategy, has become an important topic in the pursuit of long-term growth in the pavement construction field. However, the interfacial bonding behaviors of rubberized reclaimed asphalt were still ambiguous, causing the deteriorated life-performance of pavement. This study analyzed the interfacial bonding characteristics of various rubberized RAP binders with binder bond strength (BBS) test, in terms of two crumb rubber with different mesh sizes and contents, and two RAP sources with different age levels and contents. The high-temperature rheological properties were evaluated through Dynamic Shear Rheometer (DSR) test. Additionally, softening point test was also adopted to characterize the high-temperature performances. Moreover, comprehensive mechanical performance tests, including Hamburg wheel track (HWT) test, water boiling test for visual interpretation and indirect tensile strength (ITS) test were conducted to assess the feasibility of rubberized RAP mixture as pavement construction materials. It was reported that the PG temperature of asphalt was increased from 73rom ed thand the stripping of mixture under moisture reduced from 11.98% to 9.20% at least. Finally, a surface interaction model of rubberized RAP binder with colloid structure and statistical analysis were established. This research demonstrated that the reuse of end-of-life materials in pavement was feasible and provided comparable service performance. The surface interpretation with the light components trapping within gel-phase of rubber and the chemical composition oxidization of RAP would ultimately affect the bonding characteristics and properties of rubberized RAP materials, whose interfacial bond mechanism was recommended investigation before application.