Specific Surface of Hardened Portland Cement Paste as Determined by Small‐Angle X‐Ray Scattering

Abstract

Small‐angle X‐ray scattering was used to determine the specific surfaces of hardened portland cement pastes subjected to various treatments. Reasonably mature pastes yielded values of the order of 700 m 2 /g of ignited paste when examined in the original saturated condition. Drying to an intermediate relative humidity, P‐drying, and D‐drying reduce the surface areas to values of the order of 200 to 300 m 2 /g, but vacuum resaturation results in recovery of all the lost surface. Oven drying produces an additional loss in surface area, and in this case recovery on resaturation is not quite complete. The effect of w/c ratio appears to be minor, and pastes of hydrated C 3 S yield essentially the same surface areas as corresponding portland cement pastes.