Abstract:
Developing technologies that provide sustainable solutions for future pavement construction is vital given the ever-increasing demand on the supply of bitumen and good-quality pavement construction materials. Recycled Asphalt Pavements (RAP) is a technology that presents many benefits in terms of both cost and environmental savings. The presented study investigated the effect of polymers on the deformation (rutting) resistance and cracking resistance of RAP mixes. In this study, laboratory testing was conducted on six paving mixes manufactured using various proportions of RAP and polymers. The mixes contained 15%RAP, 30%RAP, a control mix, 15%RAP+polymer, 30%RAP+polymer and polymer only mix. Samples were subjected to dynamic modulus testing, flow number testing and overlay testing using an Asphalt Mixture Performance Testing machine. The inclusion of RAP resulted in notable increases in the stiffness of the mixes, particularly with a 30% RAP proportion. The addition of polymers reduced the stiffness of the mixes, most notably in the 30% RAP mix while no change in stiffness was observed for the 15% RAP mix. The presence of polymers improved the rutting resistance of all the mixes, although the presence of polymers in conjunction with RAP decreased the reflective cracking resistance of the mixes, where when the RAP content was high, the negative effects of polymers on the cracking performance of the mixes were more significant. The research results provided a valuable understanding of the behaviour of RAP mixes, and in particular, this study provided valuable performance specifications for RAP mixes for the pavement construction industry in New Zealand.
