New Additive for Use in Hot In-Place Recycling to Improve Performance of Reclaimed Asphalt Pavement Mix

Abstract

With the emphasis on sustainability in recent years, hot in-place pavement recycling has been widely used in pavement maintenance in China. However, the application of this technology on modified asphalt pavement does not proceed smoothly because the aged modified asphalt in reclaimed asphalt pavement (RAP) mix is difficult to rejuvenate. So far, few effective rejuvenating agents have been developed for modified asphalt. Therefore, new agents or new methods are called for in modified asphalt pavement recycling. The purpose of the rejuvenating agent is to promote the properties of RAP mix through the rejuvenation of the aged binder. Styrene–butadiene rubber (SBR) latex, a polymer emulsion used to blend modified asphalt with conventional asphalt, now is considered to be a new additive agent to take the place of a rejuvenator but achieve the same goal. Tests were conducted in the laboratory to measure the effect of SBR latex on RAP mix. SBR latex was found to enhance the low-temperature properties of RAP binder efficiently without causing any observable negative influence on RAP mix compaction if a proper dosage was applied. Meanwhile, SBR latex was able to improve the viscoelastic characteristics and other performance of RAP mix, including the resistance to low-temperature cracking, rutting, and moisture damage. Finally, the field application in hot in-place pavement recycling proved the feasibility and effectiveness of using SBR latex.