As shown in Fig. 6, no significant differences were observed in relation to the compressive strength of the pastes after 28 days of hydration. They varied between 66.2 and 69.0MPa. Non-decrease in the compressive strength of RHA pastes is associated with the pozzolanic activity of this mineral admixture. Thus, based on the rheological and mechanical results, 20% RHA was the more effective content to improve s0 and a, maintaining the same 28-day compressive strength of the reference paste. In this research, improving the rheological parameters of the cement-based paste was a positive effect since the previous experiments in high workability concretes (slump over 200 mm) indicated a great tendency of segregation. Thus, high s0 and a in P-RHA20 indicated better cohesiveness for similar flowability.