Laboratory performance of rejuvenated asphalt surfacing mixtures containing 30% RAP

Abstract

As the cost and demand for bitumen and aggregate resources increase, it is vital to implement more sustainable practices in asphalt pavement construction. Recycled asphalt pavement (RAP) technology involves the use of recycled asphalt material in the construction of new pavement surfaces which presents significant economic and environmental savings. In order to facilitate the further development of RAP technology, mix performance issues attributed to the use of high quantities of RAP need to be addressed. The present study investigated the use of RAP and the effect of binder rejuvenation on performance properties of hot-mix asphalt (HMA) mixes, with the aim of establishing RAP pavements as a standard practice in the asphalt paving industry in Australia and New Zealand. This study was conducted through the ARRB Group University Research Grant Support Scheme to investigate environmentally responsible technologies to improve the current road network and benefit Australian and New Zealand road agencies. In this study, laboratory performance testing was undertaken to characterise the mechanical performance properties of recycled, rejuvenated asphalt mixes. Test specimens were prepared from five mixes, all of which contained 30% RAP. The five mixes included one control mix and four mixes that contained different rejuvenation agents. Samples were subjected to overlay, dynamic modulus and wheel tracking tests. The addition of rejuvenation agents to recycled mixtures resulted in notable improvements to the cracking resistance and a decrease in dynamic modulus compared to the control mix. It was observed that rejuvenation slightly decreased deformation resistance when compared to the control, however, rutting measurements were well under standard specified limits. The results obtained from the present research provide an understanding of the effect of rejuvenation on the performance of asphalt surfacing mixes containing large quantities of RAP.