Effects of using waste high-density polyethylene on the rheological, mechanical, and thermal performance of asphalt materials

Concern for the environment has been increasingly evident in recent years, knowing that one of the main environmental problems found in urban centers is associated with the urban heat island phenomenon. In view of this environmental problem, one way to obtain cooler paved surfaces under the incidence of solar radiation is to increase their albedo, through the coloring of paved surfaces. Thus, the objective of this work was to investigate the potential of using waste high-density polyethylene (HDPE) waste to color asphalt mixture and minimize the urban heat island phenomenon due to the high reflection of HDPE colors. The research was structured in three main strands: (i) rheological characterization of the binder modified by HDPE in the contents of 1%, 2%, and 3%; (ii) mechanical analysis of asphalt mixtures with HDPE; (iii) evaluation of the use of HDPE on the asphalt surface and its contribution to the reduction of surface temperature. A statistical Student’s t test verified the significance of the mechanical performance data of the mixtures. The results showed that the addition of 2% of HDPE contributed to the asphalt binder presenting rheological benefits at high temperatures and, consequently, a gain in the mechanical performance of the asphalt mixtures. The use of HDPE on the asphalt surface provided a reduction in surface temperatures, which could be a contributing agent in the reduction of urban heat islands.