ABSTRACTDSP cement paste is prepared by hot-pressing technique in this study in order to improve its particle packing and chemical composition, and to investigate the relationship between its solid phase microstructure and mechanical strength at the porosity close to zero. The addition of silica fume improves strength development, although capillary porosities are not changed significantly. Results obtained indicate that the highest compressive strength reached are 800 MPa after 28 days hydration and oven drying at 200°C. The strength has better relation with degree of hydration or the physical density of C-S-H. the silicate anion polymerization closes not appear to influence strength.