Cement substitution by a recycled cement paste fine: Role of the residual anhydrous clinker

•RCPF just fills the granular gap left by the substituted cement in mortar mixtures.•RCPF contains around 24% of a reactive residual anhydrous clinker.•RCPF contributes in the hydration process through its anhydrous clinker.•RCPF contributes in the mechanical properties through its anhydrous clinker.•RCPF contributes in the carbonation resistance through its anhydrous clinker.