The pore structure of low porosity cement pastes containing varying quantities of silica fume has been examined using mercury intrusion porosimetry (MIP) and nitrogen adsorption (NA) measurements. The water:solid ratio for all DSP pastes studied was 0.18. It was observed that, as for conventional pastes, removal of water by solvent replacement with methanol minimizes changes to the pore structure. Vacuum or oven drying severely reduces specific surface area and obscures important trends.
It was found that capillary porosity in excess of 10 nm (100 Å) is essentially absent and that the pore volume measured can be considered an intrinsic part of the binding phase. The influence of silica fume and curing times on pore structure has been measured and the implications of the data will be discussed. Comparisons will be made with conventional cement pastes.