Mesoporous calcium silicate glasses. II. Textural characterisation

The textural features, such as the surface area and porosity (pore structure and pore volume), of crack-free homogeneous monolith gel-glasses in the binary CaO–SiO2 compositional system are analysed using nitrogen adsorption, mercury porosimetry and helium pycnometry. The first two methods, used to study the pore morphology, are in agreement leading to the conclusion that the pore system in the gel-glasses studied consists of a three-dimensional network of cavities (pores) interconnected by constrictions (throats) in the mesopore range (75–314 Å in diameter) with the pore sizes dependent on the composition of the gel-glasses. The surface area increases while the pore size decreases when the CaO content is decreased. The skeletal and bulk densities both increase when the CaO content is decreased and the gel-glasses are of approximately 30% porosity.