This study evaluated the carbonation potential of multi-recycled concrete powder and its feasibility as a partial cement replacement in mortars. First-generation (RP1) and second-generation (RP2) recycled powders were produced through repeated laboratory crushing. Mortars were then prepared by replacing cement with non-carbonated RP1 and carbonated RP1 (CRP1) at weight ratios of 6%, 13%, and 20%. The experimental results showed that RP1 decreased the 7-day compressive strength and increased water absorption due to the dilution effect. For the carbonated series, however, the effects distinctively depended on the replacement ratio. At a low replacement of 6%, the mortar specimen with CRP1 exhibited lower strength than its non-carbonated counterpart. Conversely, at a high replacement of 20%, it demonstrated 8% increase in the strength. In contrast to the strength trends, water absorption consistently decreased across all replacement ratios. Regarding carbon capture efficiency, RP1 showed a CO₂ uptake capacity of 1.66%, whereas RP2 exhibited 2.46%, representing a 1.5-fold increase. This marked increase is attributed to the accumulation of adhered old mortar during repeated recycling, which provides more active components for mineralization. These preliminary findings indicate that repeatedly recycled concrete powder possesses higher potential for carbon sequestration, suggesting its validity for future closed-loop concrete recycling systems.