Effect of Asphalt Rejuvenating Agent on Cracking Properties of Aged Reclaimed Asphalt Pavement

摘要

Hot in-place recycling (HIR) preserves distressed asphalt pavements while minimizing use of virgin binder and aggregates. The final quality of an HIR mixture depends on characteristics of the original binder, aging of the pavement surface during service, and whether or not new binder or rejuvenator was added to the mixture. An HIR mixture should maintain desired properties for additional service periods, making asphalt binder modification inevitable. Asphalt binder modifications in HIR are commonly done by adding an asphalt rejuvenating agent (ARA). However, ARA may adversely affect the qualities of new HIR and potentially fail to improve the quality of the final surface. The objective of this research was to investigate the effects of rejuvenation on HIR performance by assessing critical performance indicators such as cracking resistance, moisture susceptibility, and low temperature cracking. An experimental program was designed that included mechanical property measurements of the HIR mixture by conducting Texas overlay, thermal stress restrained specimen, and moisture susceptibility tests. HIR Samples were obtained from three Kansas Department of Transportation projects and tests were conducted on HIR mixtures with and without ARA. Study results showed significant variability in the mechanical performance of HIR mixtures, which was attributed to the variability of binders.