Typically, the strength gain mechanism in RCCP, especially at initial days (aggregate interlocking), is different from its counterparts and thus requires accurate proportioning of aggregates with good workability properties. In this study, the various fundamental parameters of RCCP mix design, viz. aggregate gradation, vebe consistency, water-cement ratio (W/C), and aggregate-cement ratio (A/C), are studied critically through the particle packing approach. The IRC: SP-68 blending approach is compared with the modified Andreasson model. The parameters considered for gradation optimization are packing density, consistency, maximum dry density (MDD), and compressive strength. The results indicated the effectiveness of IRC gradation in terms of higher packing density (1–4%), MDD (0.1–2.7%), and compressive strength (12–67%) over the modified Andreasson model. The finding from this analysis suggests that designing RCCP mixes with the A/C between 5.7 and 6 and W/C in the range of 0.36–0.40 could achieve better consistency and strength properties. © 2023, Transportation Research Group of India.