The utilisation of reclaimed asphalt pavement (RAP) as a suitable substitute for natural aggregate and binder offers an energy-saving and cost-effective approach to enhance the performance of asphalt mix. Realising the potential use of RAP as a promising recycling technique, many countries are seeking to recycle RAP as part of the global effort to address the rising challenge of climate change and contribute to a sustainable environment. This study aimed to develop an integrated approach to determine the amount of RAP to be used in an asphaltic concrete wearing course with 14 mm nominal maximum aggregate size (ACW14). The RAP was incorporated with two waste materials comprising waste engine oil (WEO) as a rejuvenator and Crumb Rubber (CRM) as a binder modifier. A total of five different mixes, which include R0 (control mix), R30, R50, R70, and R100 (replacement of 30%, 50%, 70%, and 100% of RAP aggregates in the mix, respectively) were evaluated. The Marshall parameters, resilient modulus (M_R), indirect tensile fatigue, moisture susceptibility, and mass loss (ML) tests were conducted to investigate the performance of each mix. Finally, an arbitrary scale was developed to optimise the RAP content. The results showed that the Marshall parameters, moisture susceptibility, and ML values of the RAP mixes met the criteria outlined in the standard. According to the M_R performance, the R50, R70, and R100 mixes were more resilient than the R0. In terms of fatigue resistance, the R30, R50, and R70 mixes showed better performance than the R0. Overall, the collective performance of all RAP mixes was above the R0 and it increased with the increment of RAP content. Therefore, it was possible to design ACW14 mixes with up to 100% RAP in combination with WEO and CRM.

The present study aimed to investigate the properties of reclaimed asphalt pavement (RAP) mixes to determine their suitability for preparing conventional hot mix asphalt (HMA) for wearing courses. To effectively recover the properties of the aged binder, the RAP was combined with two waste materials such as waste engine oil (WEO) as a rejuvenator and crumb rubber (CR) as a binder modifier. The effect of WEO on the rheological and physical characteristics of the extracted aged binder was investigated by analysis. Five different HMA mixes were prepared with different percentages of RAP aggregate replacing virgin aggregates at 0%, 30%, 50%, 70%, and 100%. The flow, volumetric properties, and Marshall stability tests were examined in this study. Every RAP mix showed adherence to the 8.0 kN minimum stability requirement. The Marshall flow showed an increasing trend as the binder and RAP content increased. Notably, each mix met the minimum (2.0 kN/mm) Marshall quotient criteria. The results demonstrated that the optimum binder content (OBC) gradually decreased as the RAP content rose. With the increase in RAP content, there was a noticeable increase in the binder saving rate. Particularly, 79.7% less binder was used in the R100 mix compared to the R0 mix. Statistical analysis clearly showed that the amount of RAP and binder significantly influences the effectiveness of the mix’s design. the effectiveness of the mix’s design. Therefore, the combination of CR and WEO allows for the creation of HMA compositions with up to 100% RAP.