Recycled polyethylene waste as binder stabilizer for SMA mix in gulf environment

Each year, millions of tons of household and industrial waste, including plastic, are responsible for harming the environment through burning, landfilling, or going to dump in open water. Waste plastic disposal is a critical issue faced by municipalities in modern cities. In addition, the development of hundreds of kilometers of roads worldwide leads to the consumption of vast quantities of raw materials and the depletion of valuable natural resources. The high expense of virgin polymers and rising plastic waste have shifted the research focus toward green pavements that utilize waste plastics. Therefore, this research aims to investigate the use of recycled plastic waste as a binder modifier for Stone Mastic Asphalt mix (SMA). The high-temperature performance of the Recycled Polyethylene Modified Binder (RPMB) has been evaluated with various percentage dosages to satisfy the environment of the Gulf region. In addition, the impact of RPMB on the SMA mix was studied through three performance tests, drain down resistance, moisture damage resistance, and rutting performance. The results showed continuous improvement in rheological properties with increased recycled polyethylene (RP) content by up to 6%. The RP enhances the binder properties such as the rutting parameter, non-recoverable compliance, and viscosity to meet the high-temperature performance requirement for heavy traffic (UPG 76 H) of most roads in the gulf environment. However, the results showed that RPMB could not meet the recovery requirement set by AASHTO TP 70. That is due to RP's plastomer nature. Therefore, it is necessary to supplement some proportion of the RP with an elastomeric polymer. Further, the results of SMA mix properties with RPMB showed remarkable improvement over than control mixture in terms of resistance to drain down, moisture damage, and rutting by 55.1%, 52.6%, and 96.4, respectively.