A comparison of rejuvenator and sryrene–butadiene rubber latex used in hot in-place recycling

With the government promoting use of hot in-place recycling (HIR) in China, the performance of HIR pavement has become a topic of intensive study. HIR processes had been using rejuvenator to restore properties of aged binder in the past, but it was found that rejuvenator is not sufficient in reconstituting the physical and chemical properties of aged polymer-modified asphalt, and that it is inclined to increase rutting potential. Sryrene–butadiene rubber (SBR) latex was then brought up as a proper substitute for rejuvenator in recent years. In this paper, both rejuvenator and SBR latex are evaluated and compared in the HIR process with modified asphalt binder. Comprehensive tests in laboratory and field trials were conducted to evaluate the properties of recycled binder and recycled mixtures. The results show that SBR latex increases the viscosity of aged binder, meanwhile it improves the rutting resistance and fatigue cracking resistance of reclaimed asphalt pavement (RAP) significantly, and that rejuvenator has adverse effect on both rutting and fatigue cracking resistance of RAP. Also SBR latex shows better application performance than rejuvenator in the moisture susceptibility and low-temperature cracking resistance of RAP. Both HIR trials with rejuvenator and SBR latex have maintained a high level of service since open to traffic, but trials with SBR latex is observed to be more promising in rutting resistance than those with rejuvenator.