Dependence of efficiency of pressure compaction on the cement type used

The results of the study on the properties of the pastes, with w/c ratio 0.20–0.10, compacted in the fresh state by the pressures between 27 and 82 MPa are given. The comparison of their properties with those found at the reference non-pressured cement pastes prepared with w/c ratio 0.30 showed the significantly increased compressive strength. Two effects were the cause: the significant decrease of the initial porosity due to the extremely low w/c ratios and the mechanical compaction of the fresh pastes. It has been found a significant increase of the effectiveness of the pressuring by the cement quality decrease. The long-term development of the properties of the pressured cement pastes is similar to the non-pressured cement pastes. At the conservation of the properties differences in the benefit of the pressured materials.