Use of Rejuvenator,Styrene-Butadiene Rubber Latex,and Warm-Mix Asphalt Technology to Achieve Conventional Mixture Performance with 50% Reclaimed Asphalt Pavement

To reduce the demand on new asphalt and aggregates, more attention has been paid to increasing reclaimed asphalt pavement (RAP) contents used in asphalt paving mixtures. However, Chinese transportation departments are reluctant to use high RAP contents in practice, partially because of the performance of high RAP mixtures, its possible effectiveness, and potential rutting problems caused by asphalt rejuvenators. An investigation was done of the effect of styrene-butadiene rubber (SBR) latex and a warm-mix asphalt (WMA) agent on RAP mixes. The objective was to produce mixtures with high RAP content that demonstrate similar or better pavement performance than the conventional hot-mix asphalt. In this study, different laboratory tests were conducted on high RAP mixtures with a rejuvenator, SBR latex, and a WMA agent. The results illustrated that the asphalt rejuvenator partly recovers the RAP binder performance and has a negative effect on the rutting performance of mixtures, while SBR latex can improve both high-temperature and low-temperature performance with the rejuvenator. Using the WMA agent can satisfy the specifications and production tolerances of volumetric properties for high RAP mixes. Finally, it is found that the mixture with 50% RAP and SBR latex can supply a better fatigue performance, low-temperature performance, and moisture-resistant performance than the conventional hot-mix asphalt mixture.