摘要

The phenomenon of water vapour sorption by powdered cement constituents exposed to different relative humidities and temperatures was studied. The individual clinker phases C(3)S, C(2)S, C(3)A, C(4)AF, calcium sulfates and CaO were tested. Using a water sorption balance, the amount of chemically and physically sorbed water per unit of surface area of the powders and the relative humidity at which water sorption starts to occur on the phases were determined. Various cement clinker phases prehydrate very differently. CaO and C(3)A were found to be most reactive towards water vapour whereas the silicates react less. CaO starts to sorb water at very low RHs and binds it chemically. Beginning at 55% RH, orthorhombic C(3)A also sorbs significant amounts of water and binds it chemically and physically. Water sorption of C(3)S and C(2)S only begins at 74% RH, and the amount of water sorbed is minor. Calcium sulfates sorb water predominantly physically.

  • 出版日期2011-11