Surface area and pore structure of hardened Portland cement/silica fume pastes containing a superplasticizer

Surface characteristics such as specific surface area, total pore volume, hydraulic pore radius and pore size distribution have been evaluated for hardened Portland cement/silica fume pastes containing different amounts of BVF superplasticizer (naphthalene sulphonate addicrete). The derived parameters indicate that the surface properties were greatly affected by the amount of superplasticizer employed. The pozzolanic reaction between silica fume and the Free lime released during the hydration of Portland cement, as well as the production of a more dense structure produced by the addition of BVF superplasticizer accompanied by decreasing initial water/solid ratios, resulted in hardened cement pastes with a close-textured structure and the predominance of micropores and/or mesopores with a limited size. Such a structure produced dense pastes with improved mechanical properties.