Performance of Recycled Asphalt Pavement Mixes – Comparing New Zealand Experience to American Experience

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 paper investigated the use of RAP in New Zealand with the aim of establishing RAP as a standard pavement construction technology. The study findings were used to establish performance standards for RAP mixes in New Zealand. In this study, laboratory testing was undertaken to characterise the performance of asphalt mixes containing different quantities of RAP. Samples were prepared from three mixes containing 15% RAP, 30% RAP, and a control mix, and the samples were subjected to dynamic modulus, flow number and overlay testing using an Asphalt Mixture Performance Testing machine. The inclusion of 30% RAP resulted in notable increases in the deformation resistance of an asphalt mix, while the inclusion of 15% RAP only had marginal improvements to the deformation resistance of an asphalt mix. The presence of 30% RAP however increased the susceptibility of asphalt mixes to reflective cracking. No notable difference was observed between the cracking susceptibility of the 15% RAP mix and the control mix. The research results provide a valuable understanding of the performance of RAP and through this research new testing protocols were established for the use of RAP in the New Zealand context.