Investigation on the performance properties of asphalt mixtures prepared with RAP and WMA additives at binder and mixture levels.

In consideration of both economic and environmental benefits, recycled materials, such as Reclaimed Asphalt Pavement (RAP), have been commonly used in pavement construction for decades (Büchler et al., 2018). On one hand, a number of research efforts have been conducted to evaluate the possibility of using a high amount of RAP in the pavement construction, leading to a wide acceptance on the use of RAP up to 40% in content (Poulikakos et al., 2017; Büchler et al., 2018; Wang et al., 2019). On the other hand, only limited studies focused on the combined use of RAP with other techniques or materials, for example, the Warm Mix Asphalt (WMA) technology for the mixture design and paving. In this study, the possibility of using a high amount of RAP together with WMA technologies to achieve similar performance properties compared with the conventional Hot Mix Asphalt (HMA) was experimentally investigated. The original idea of this research develops and expands from the interlaboratory work proposed by the RILEM technical committee (TC) entitled Asphalt Pavement Recycling 264-RAP-TG2 (RILEM, 2015). This TC was originally proposed in 2015, its objective is to enhance the fundamental understanding of the interactions between recycled asphalt (RA) materials and new fresh materials in asphalt paving mixtures, and the combination of RAP with various technologies and sustainable materials. In this paper, the recycled asphalt (RA) mixture, with an NMAS equals to 11.2 mm, provided by the RILEM committee was used as reference material. The following steps were conducted to evaluate the possibility of combined use of RAP and WMA at both mixture and binder scales