Some factors affecting the surface area of hydrated portland cement as determined by water-vapor and nitrogen adsorption

Abstract

Brunauer-Emmett-Teller (BET) surface areas of hydrated portland cement have been calculated from water-vapor and nitrogen-adsorption data. The adsorption and desorption of wat~r vapor caused. measurable decreases in specific surface areas by both water-vapor and mtrogen adsorptIOn. Changes were !tlso produced by wetting and drying. The adsorption and desorption of nitrogen at the boiling point of liquid nitrogen did not produce similar effects. The specific surface and nonevaporable-water content of a hydrated cement are also somewhat dependent on the initial drying treat ment. The effect of measuring water-vapor surface a nd nonevaporable water with specimens dried for different periods of time is also considered.