## 4 Conclusions  
This study examined an integrated approach to optimise the RAP content of ACW14 mixes using high RAP content and waste materials (WEO and CRM) with the following conclusions:  
1. The OBC of all RAP mixes was below the R0 value. It was demonstrated that the OBC values decreased gradually as the RAP content increased. Furthermore, it was anticipated that the use of higher RAP percentages in the asphalt mixes would lead to a significant revenue in the related pavement construction field.
2. The stability of all RAP mixes was higher than the R0 (10.2 kN) as well as the standard limits (8.0 kN). The increment of RAP content was found to increase the flow. The findings also showed that all RAP mixes satisfied the Marshall stability, flow, and volumetric properties criteria.
3. The value of M\({}_{\text{R}}\) increased with the increment in RAP content. All RAP mixes were more resilient than the R0 except the R30 mix, in which the M\({}_{\text{R}}\) value obtained was 1.6% lower than the R0. Thus, it was concluded that the combined use of WEO and CRM was effective to obtain a balanced M\({}_{\text{R}}\) value.
4. The TSR values of all RAP mixes were above the R0 (88.7%) and standard requirement (80%). Thus, it can be summarised that the RAP mixes were sufficiently resistant to moisture susceptibility.
5. In terms of fatigue performance, the R30, R50, and R70 mixes produced a higher fatigue resistance compared to the R0. The R100 mix was approximately 5% less resistant to fatigue cracking than the R0.
6. The lower threshold value (15%) of all mixes from the ML test showed promising results and indicated that the mixes were highly resistant to ravelling and sufficiently durable.
7. The arbitrary scale was successfully developed as an effective performance evaluation method to determine the five major performance test results. The collective performance of all RAP mixes was higher than the R0 with increased performance as the RAP content increased. Therefore, 100% RAP mix can be used in ACW14 mix design without significantly reducing the asphalt mix's performance.  
Figure 7: Comparison of the overall performance of the five mixes based on the arbitrary scale.  
**Author Contributions:** Conceptualisation, M.Z.H.K., S.K. and M.R.I.; methodology, M.Z.H.K., S.K. and M.R.I.; formal analysis, M.Z.H.K., A.M.B. and O.A.; investigation, M.Z.H.K. and A.M.B.; resources, S.K.; writing--original draft preparation, M.Z.H.K.; writing--review and editing, S.K., H.Y.B.K., M.R.I. and A.M.B.; supervision, S.K. and M.R.I.; project administration, S.K.; funding acquisition, S.K. and H.Y.B.K. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This study was funded by the Universiti Malaya, grant name \"Others MOHE--Top 100 (IIIRG)-IISS (IIRG009C-19 IISS)\" and the Universiti Tenaga National (UNITEN), Malaysia, grant number \"BOLD 2020 RIO10517844/046\". The first author was financially supported by the Local Government Engineering Department, Bangladesh.  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** All data used in this research can be provided upon request.  
**Acknowledgments:** The authors would like to acknowledge the Universiti Malaya and Universiti Tenaga National (UNITEN), Malaysia. The first author gratefully acknowledges the Local Government Engineering Department, Bangladesh, for the financial support.  
**Conflicts of Interest:** The authors declare no conflict of interest.