Investigation of road performances of rejuvenated styrene-butadiene-styrene modified asphalt mixture

Exploring the effective recycling of waste styrene-butadiene-styrene block copolymer (SBS) modified asphalt mixture is the difficulty and hotspot in the field of road materials research. Common rejuvenation method and reactive rejuvenation method were used to recover the road performances of aged SBS modified asphalt mixture (ASMBM) in this paper. The recovery effect of high- and low-temperature performance, fatigue resistance and water stability for ASMBM after rejuvenation was studied, and the road performance development of ASMBM after reactive rejuvenation in the early stage was also investigated. The results show that reactive rejuvenation method could significantly enhance the Marshall stability and rutting resistance of rejuvenated ASMBM, and further improve its low-temperature cracking resistance as compared with common rejuvenation method, which attributes to the reconstruction of aged SBS cross-linking structure and its improvement on the interface stability of rejuvenated mixture. Meanwhile, the fatigue life of reactive rejuvenated ASMBM under strain level of 400 με is 26.6 % higher than that of common rejuvenated mixture. Water stability test results show that reactive rejuvenation is more beneficial to restore the water-immersed Marshall stability and Hamburger rutting resistance of ASMBM. Furthermore, the road performances of reactive rejuvenated ASMBM have a further improvement with the extension of time in the early stage after rejuvenation, its Marshall stability, the freeze-thaw splitting strength ratio and water-immersed Marshall stability could restore to the initial level of fresh mixture. Thus, reactive rejuvenation method is more conducive to realizing the high-performance recycling of waste SBS modified asphalt mixture and enhance its recycling value.